topic 3 genetics asexual reproduction – only one parent, reproduction by mitosis or binary fission
TRANSCRIPT
![Page 1: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/1.jpg)
Topic 3Genetics
![Page 2: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/2.jpg)
asexual reproduction – only one parent, reproduction by mitosis or Binary fission
![Page 3: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/3.jpg)
Biotechnology--The application of the principles of engineering and technology to the life sciences; bioengineering
![Page 4: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/4.jpg)
body cell— (soma cell) any cell in the body that is not a sex cell
![Page 5: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/5.jpg)
Bond--a mutual attraction between two atoms
![Page 6: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/6.jpg)
Centriole—one of two tiny structures in an animal cell that helps form spindle fibers
![Page 7: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/7.jpg)
Centromere—connection between two homologous chromosomes
![Page 8: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/8.jpg)
Cytokinesis—division of the cytoplasm
![Page 9: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/9.jpg)
Chromosome-- threadlike structure within the nucleus containing the genetic information that is passed from one generation of cells to the next
![Page 10: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/10.jpg)
Chromatid—one side of a homologous pair of chromosomes
![Page 11: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/11.jpg)
Clone-genetically identical organism produced by a single cell
![Page 12: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/12.jpg)
DNA-- deoxyribonucleic acid, the hereditary material in humans and almost all other organisms
![Page 13: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/13.jpg)
Egg-- female gamete that is haploid
![Page 14: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/14.jpg)
Expressed—able to be seen in offspring
![Page 15: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/15.jpg)
Gene-- sequence of DNA that codes for a protein and thus determines a trait.
![Page 16: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/16.jpg)
genetic engineering-- process of making changes in the DNA code of living organisms
![Page 17: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/17.jpg)
genetic recombination—recombination of genes during sexual reproductionHeredity-- the passing of traits to offspring
Cell cycle-- series of events that cells go through as they grow and divideMitosis—division of nucleus creating diploid cells
![Page 18: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/18.jpg)
Mutation-- change in a DNA sequence that affects genetic information
![Page 19: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/19.jpg)
Replicate— copying process by which a cell duplicates its DNA
![Page 20: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/20.jpg)
selective breeding-- method of improving a species by allowing only those individual organisms with desired characteristics to produce the next generation
![Page 21: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/21.jpg)
sexual reproduction-- process by which two cells from different parents unite to produce the first cell of a new organism
![Page 22: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/22.jpg)
Sperm—male gamete that is haploid
![Page 23: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/23.jpg)
Spindle-- fanlike microtbule structure that helps separate the chromosomes during mitosis
![Page 24: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/24.jpg)
Subunit—parts DNA can be broken down into: Deoxyribose sugar, Phosphate, nucleic acid (A,T,G,C)All three together are called a nucleotide
![Page 25: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/25.jpg)
Template— pattern used to make DNA, RNA, or proteins
![Page 26: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/26.jpg)
Traits-- specific characteristic that varies from one individual to another
Hw: Do crossword puzzle as bonus points on your quiz tomorrow
![Page 27: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/27.jpg)
Heredity and Genes
Heredity is the passing of genetic information from one generation to the next through reproduction.
The hereditary information (DNA) is organized in the form of genes located in the chromosomes of each cell.
![Page 28: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/28.jpg)
Chromosomes are found in the cell nuclei, and contain the DNA molecules. It is the DNA molecules that carry the genetic information of the cell.
![Page 29: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/29.jpg)
A human cell contains many thousands of genes in its nucleus, and each gene carries a separate piece of coded information
![Page 30: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/30.jpg)
The traits inherited by an individual can be determined by one pair of genes or by several pairs of genes. A single gene pair can sometimes influence more than one trait.
![Page 31: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/31.jpg)
Methods of Reproduction
There are two common methods of reproduction: asexual and sexual.
![Page 32: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/32.jpg)
Asexual reproduction -- involves one parent or individual (often a single-celled organism)
Identical genetic copies are known as clones
Offspring are usually identical to the parent
all the genetic instructions (genes) come from one individual or parent.
![Page 33: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/33.jpg)
BacteriaBinary fission– type of mitosis
![Page 34: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/34.jpg)
Yeast, Hydra
Budding, unequal cytoplasmic division during mitosis
![Page 35: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/35.jpg)
tubers, bulbs, runners, and grafting are types of vegetative propagation.Part of plant grows new plant
![Page 36: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/36.jpg)
Bread Mold-- sporulation
Starfish/ Planaria– fragmentation/ regeneration(new organism grows from a piece of the organism)
![Page 37: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/37.jpg)
Parthenogenesis--- makes diploid eggs that develop into a new organism
![Page 38: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/38.jpg)
The division of the nucleus during the M phase of the cell cycle is called ___________________.mitosis
Interphase is divided into 3 phases1. ____________2. ____________3. ___________
G1—cell growthS –DNA replication
G2 – prep for mitosis
![Page 39: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/39.jpg)
The 4 phases of Mitosis are:1.____________2._____________3._____________4._____________
prophase
Metaphaseanaphasetelophase
In plant cells a _______________ forms midway of the cell.
Cell plate
![Page 40: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/40.jpg)
• Sexual reproduction-- involves two parents.Each parent produces sex cells. Sperm are the sex cells produced by the male; Egg is the sex cell produced by the female.
![Page 41: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/41.jpg)
The offspring that results from sexual reproduction therefore receives half of its genetic information from the female parent (via the egg) and half from the male parent (via the sperm).
![Page 42: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/42.jpg)
Chromosome Number
All organisms have different numbers of chromosomes.A body cell in an adult fruit fly has 8 chromosomes: 4 from the fruit fly's male parent, and 4 from its female parent.
![Page 43: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/43.jpg)
These two sets of chromosomes are
A cell that contains both sets of homologous chromosomes is said to be .
diploid
homologous
![Page 44: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/44.jpg)
The of sexually reproducing organisms contain only a single set of chromosomes, and therefore only a single set of genes. These cells are .
gametes
haploid
![Page 45: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/45.jpg)
What happens during the process of meiosis?
Meiosis is a process of division in which the number of chromosomes per cell is cut in through the of homologous chromosomes in a diploid cell.
reduction
halfseparation
![Page 46: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/46.jpg)
Meiosis involves divisions, and .
By the end of meiosis II, the diploid cell that entered meiosis has become 4 haploid cells.
Two meiosis I meiosis II
![Page 47: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/47.jpg)
Meiosis I
Cells undergo a round of DNA replication, forming duplicate chromosomes.
![Page 48: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/48.jpg)
Each chromosome pairs with its corresponding homologous chromosome to form a tetrad. Also called synapsisThere are 4 chromatids in a tetrad.
![Page 49: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/49.jpg)
When homologous chromosomes form tetrads in meiosis I, they exchange portions of their chromatids in a process called .
crossing-over
![Page 50: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/50.jpg)
Crossing-over produces new of alleles.
combinations
Spindle ______________ attach to the chromosomes.
The fibers pull the _________________ chromosomes toward opposite ends of the cell.
____________________ membranes form.
The cell ____________________ into two cells.
The two cells produced by meiosis I have chromosomes and alleles that are different from each other and from the diploid cell that entered meiosis I.
fibers
homologous
Nuclearseparates
![Page 51: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/51.jpg)
Meiosis II
The two cells produced by meiosis I now enter a _____________ meiotic division.
Unlike meiosis I, neither cell goes through chromosome__________________.
Each of the cell’s chromosomes has 2 ____________________.
second
replication
chromatids
![Page 52: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/52.jpg)
A to B Meiosis I results in two ______________(N) daughter cells, each with half the number of chromosomes as the ________________cell.
C The chromosomes line up in the ______________ of cell.
D The sister ____________________ separate and move toward ______________ ends of the cell.
E Meiosis II results in ______________ haploid (N) daughter cells
haploid
original
center
chromatidsopposite
four
![Page 53: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/53.jpg)
Gamete FormationIn male animals, meiosis results in four equal-sized gametes called sperm.
In many ____________ animals, only one egg results from meiosis. The other three cells, called ___________ bodies, are usually not involved in reproduction.
female
polar bodies
![Page 54: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/54.jpg)
Mitosis results in the production of two genetically identical diploid cells. Meiosis produces four genetically different haploid cells.
![Page 55: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/55.jpg)
Mitosis •Cells produced by mitosis have the same number of chromosomes as the original cell.
•Mitosis allows an organism to grow and replace cells.
•Some organisms reproduce asexually by mitosis.
![Page 56: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/56.jpg)
Meiosis •Cells produced by meiosis have half the number of chromosomes as the parent cell.
•These cells are genetically different from the diploid cell and from each other.
•Meiosis is how sexually reproducing organisms produce gametes.
![Page 57: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/57.jpg)
When a sperm and egg combine to form a new cell with a complete set of genetic instructions, a unique combination of genes results. The term for this is genetic recombination.
![Page 58: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/58.jpg)
Hw: pg 42 Questions 1-7
![Page 59: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/59.jpg)
The Genetic CodeThe inherited instructions (genes) that are passed from parent to offspring exist in the form of a chemical code called the genetic code. It is contained in the DNA molecules of all organisms. DNA molecules resemble a flexible, twisted ladder formed from many smaller repeating units
![Page 60: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/60.jpg)
Like other large molecules of life, the DNA molecule is made of thousands of smaller sections called subunits.
Each subunit has three chemical parts: 1. a sugar2. a phosphate3. a base.
![Page 61: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/61.jpg)
The bases of a DNA molecule are represented by the letters
1. A 2. G3. C4. T
![Page 62: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/62.jpg)
The four subunits of DNA molecules are arranged in pairs, each subunit forming one side and half ofone rung of the "twisted ladder."
![Page 63: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/63.jpg)
Watson and Crick's model of DNA was a double helix, in which two strands were wound around each other.
![Page 64: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/64.jpg)
Watson and Crick discovered that hydrogen bonds can form only between certain base pairs
• adenine and thymine
• guanine and cytosine.
This principle is called base pairing.
![Page 65: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/65.jpg)
DNA and Chromosomes
In _________cells, DNA is located in the cytoplasm.Most prokaryotes have a __________ DNA molecule containing nearly all of the cell’s genetic information.
prokaryotic
single
![Page 66: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/66.jpg)
Many _______________ have 1000 times the amount of DNA as prokaryotes.Eukaryotic DNA is located in the cell ____________ inside chromosomes. The number of chromosomes varies widely from one species to the next.
eukaryotic
nucleus
![Page 67: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/67.jpg)
Eukaryotic Chromosome StructureEukaryotic chromosomes contain DNA wrapped around _______________ called histones. The strands of nucleosomes are _____________ coiled and supercoiled to form chromosomes.
proteins
tightly
![Page 68: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/68.jpg)
What happens during DNA replication?DNA Replication
Each strand of the DNA _______________ helix has all the information needed to ___________________ the other half by the mechanism of base pairing
double
reconstruct
In most prokaryotes, DNA replication begins at a single point and continues in two directions.
![Page 69: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/69.jpg)
In eukaryotic chromosomes, DNA replication occurs at _______________of places. Replication proceeds in ________________ directions until each chromosome is completely copied.The sites where separation and replication occur are called ________________ forks.
hundreds
Both
replication
![Page 70: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/70.jpg)
DNA replication videoWhat happens during DNA replication?DNA Replication
Each strand of the DNA _______________ helix has all the information needed to ___________________ the other half by the mechanism of base pairing.
double
reconstruct
![Page 71: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/71.jpg)
In most prokaryotes, DNA replication begins at a ___________ point and continues in two directions.In eukaryotic chromosomes, DNA replication occurs at _______________of places.
Single
hundreds
![Page 72: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/72.jpg)
Replication proceeds in ________________ directions until each chromosome is completely copied.The sites where separation and replication occur are called ________________ forks.
both
replication
![Page 73: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/73.jpg)
RNANote: no thymine, it is replaced by uracil
![Page 74: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/74.jpg)
________ are coded DNA instructions that control the ___________ of proteins. Genetic ______________ can be decoded by copying part of the ___________ sequence from DNA into RNA. RNA contains __________ information for making proteins.
Genesproduction
messages
nucleotidecoded
![Page 75: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/75.jpg)
The Structure of RNARNA consists of a long chain of nucleotides.Each nucleotide is made up of a 5-carbon sugar (Ribose)a phosphate groupand a nitrogenous base.
Draw this
Ribose
![Page 76: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/76.jpg)
There are three main differences between RNA and DNA:
•The sugar in RNA is _________ instead of deoxyribose. •RNA is generally _______-stranded.•RNA contains _________ in place of thymine.
ribose
single
uracil
![Page 77: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/77.jpg)
There are three main types of RNA:•_______________•________________•transfer RNA
Messenger RNARibosomal RNA
![Page 78: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/78.jpg)
• Messenger RNA (mRNA) carries copies of instructions for assembling ____________ acids into proteins.
• Ribosomes are made up of proteins and ___________ RNA (rRNA).• During protein construction,
___________ RNA (tRNA) transfers each amino acid to the ribosome.
amino
ribosomal
transfer
![Page 79: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/79.jpg)
What is transcription?
Transcription
RNA molecules are produced by __________ part of a ___________ sequence of DNA into a _______________ sequence in RNA.
This process is called transcription.
copying nucleotide
complementary
![Page 80: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/80.jpg)
Transcription requires the __________ RNA polymerase.enzyme
During transcription, RNA polymerase binds to DNA and separates the DNA strands.
RNA polymerase then uses one strand of DNA as a template from which nucleotides are assembled into a strand of RNA.
![Page 81: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/81.jpg)
RNA polymerase binds only to _____________ of DNA known as promoters.
____________________ are signals in DNA that indicate to the enzyme where to bind to make RNA.
http://www.youtube.com/watch?v=ztPkv7wc3yU&feature=related
regions
promoters
![Page 82: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/82.jpg)
The Genetic Code
![Page 83: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/83.jpg)
The genetic code is the “language” of mRNA instructions.
The code is written using four “letters” (the bases: A, U, C, and G).
A _________ consists of three consecutive nucleotides on mRNA that specify a particular amino acid.
codon
![Page 84: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/84.jpg)
Each codon specifies a __________ amino acid that is to be placed on the polypeptide chain.
Some amino acids can be specified by more than _________ codon.
particular
one
![Page 85: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/85.jpg)
![Page 86: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/86.jpg)
There is one codon _______that can either specify the amino acid methionine or serve as a “start” codon for protein synthesis.
There are ________ “stop” codons that do not code for any amino acid. These “stop” codons signify the end of a polypeptide.
AUG
three
![Page 87: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/87.jpg)
Translation is the __________ of an mRNA message into a polypeptide chain (protein).
Translation takes place on ribosomes.
During translation, the cell uses information from messenger RNA to produce proteins.
decoding
![Page 88: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/88.jpg)
Messenger RNA is ______________ in the nucleus, and then enters the cytoplasm where it ______________ to a ribosome.
Translation begins when an mRNA molecule attaches to a ____________.
transcribed
attaches
ribosome
![Page 89: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/89.jpg)
As each codon of the mRNA molecule moves through the_____________, the proper amino acid is brought into the ribosome by tRNA.
ribosome
![Page 90: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/90.jpg)
In the ribosome, the ___________ is transferred to the growing polypeptide chain.
Each tRNA molecule ____________ only one kind of amino acid.
In addition to an amino acid, each tRNA molecule has ______ unpaired bases.
Amino acid
carries
three
![Page 91: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/91.jpg)
These bases, called the ___________, are complementary to one mRNA codon.The ribosome binds new tRNA molecules and amino acids as it moves along the mRNA.The process __________ until the ribosome reaches a stop codon.
anticodon
continues
![Page 92: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/92.jpg)
The Roles of RNA and DNA
The cell uses the DNA “master plan” to prepare RNA “_________.”
The DNA stays in the ___________.
The RNA molecules go to the ______ building sites in the cytoplasm—the ribosomes.
blueprint
nucleus
protein
![Page 93: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/93.jpg)
Genes and Proteins
Genes contain instructions for assembling________.
Many proteins are enzymes, which catalyze and _________ chemical reactions.
proteins
regulate
![Page 94: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/94.jpg)
Proteins are each specifically designed to build or operate a _____________ of a living cell.
The sequence of bases in DNA is used as a ______________ for mRNA.
The codons of mRNA specify the sequence of amino acids in a __________________.
component
template
protein
![Page 95: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/95.jpg)
Do Questions 8-22, page 51 and 52 in workbook.
Classwork !!!!!!!!!!!!! This means no talking and do the work!!!! Must be done on separate answer sheet and turned in for grade.
![Page 96: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/96.jpg)
Mutations
•Mutations are changes in the DNA _______________that affect genetic information.
sequence
![Page 97: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/97.jpg)
•Types of gene mutations (changes in a single gene):
Substitution--__________________
–Original strand: TAC GCA TGG–Mutated strand: TAC GTA TGG
One nucleic acid is substituted for another
![Page 98: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/98.jpg)
• Insertion—________________________
–Original strand: TAC GCA TGG
–Mutated strand: TAT CGC ATG G
One nucleic acid is added in
![Page 99: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/99.jpg)
Deletion – ____________________________• Original strand: TAC GCA TGG• Mutated strand: TCG CAT GG
• ___insertions______and _____deletion_____cause the biggest problems because everything shifts–This is called a ___mutation_______ This makes the code unreadable
One nucleic acid is left out
![Page 100: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/100.jpg)
Example:Normal DNA-THEREDFOXATETHEBIGRAT
Insertion mutation-THEEREDFOXATETHEBIGRAT
Deletion mutation-THEEDFOXATETHEBIGRAT
![Page 101: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/101.jpg)
Types of chromosomal Mutations (______________________________________):
CHANGE IN WHOLE CHROMOSOME
![Page 102: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/102.jpg)
HW DO PAGE 52 AND 53 QUESTIONS 23-31
![Page 103: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/103.jpg)
DNA and Individuality Genes are expressed differently in organisms based on environmental conditions NATURE VS. NURTURE
Two organisms (twins) can have the same DNA, but it might show up differently due to the environment
![Page 104: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/104.jpg)
Selective BreedingQuestion: What is the purpose of selective breeding?
Examples: Nearly all domestic ____________ and most Crop plantshave been produced by selective breeding.
animals
Selective breeding allows only those organisms with desired characteristics to produce the next generation
![Page 105: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/105.jpg)
![Page 106: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/106.jpg)
A) Hybridization
Hybridization is the crossing of dissimilar individuals to bring together the ________ of both organisms.
Hybrids, the individuals produced by such crosses, are often ____________ than either of the parents.
best
hardier
![Page 107: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/107.jpg)
B) Inbreeding Inbreeding is the continued breeding of individuals with ______________ characteristics.
Inbreeding helps to ensure that the ________________ that make each breed unique will be ________________.
Warning! Serious genetic problems can result from excessive inbreeding.
similar
characteristics
preserved
![Page 108: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/108.jpg)
Increasing VariationQuestion: Why might breeders try to induce mutations?
Answer: Breeders induce mutations to ________________ genetic variation in a population.
increase
![Page 109: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/109.jpg)
Mutations
Mutations occur spontaneously, but breeders can increase the mutation rate by using _______________ and __________________.
Breeders can often produce a few mutants with desirable characteristics that are not found in the original population.
radiationchemicals
![Page 110: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/110.jpg)
A) Producing New Kinds of BacteriaIntroducing mutations has allowed scientists to develop hundreds of useful bacterial strains, including bacteria that can clean up _______ ___________.Oil spills
![Page 111: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/111.jpg)
B) Producing New Kinds of Plants
Mutations in some plant cells produce cells that have ___________ or ____________ the normal number of chromosomes.
This condition, known as _______________, produces new sof plants that are often larger and stronger than their diploid relatives.
Warning! Polyploidy in animals is usually fatal.
double triple
polyploidy
![Page 112: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/112.jpg)
The Tools of Molecular Biology
Question: How do scientists make changes to DNA?
Answer: Scientists use their knowledge of the _______________ of DNA and its _________________ ___________________ to study and change DNA molecules.
structurechemical
properties
![Page 113: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/113.jpg)
Scientists use different techniques to:______________ DNA from cells_________ DNA into smaller piecesidentify the sequence of bases in a DNA
moleculemake unlimited ___________ of DNA
In ___________ ________________, biologists make changes in the DNA code of a living organism.
![Page 114: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/114.jpg)
DNA ExtractionDNA can be extracted from most cells by a simple ________________ procedure.The cells are opened and the DNA is ___________________ from the other cell parts.
![Page 115: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/115.jpg)
Cutting DNAMost DNA molecules are too ____________ to be analyzed, so biologists cut them into smaller fragments using ____________ __________________. Each restriction enzyme cuts DNA at a specific sequence of __________.
![Page 116: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/116.jpg)
![Page 117: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/117.jpg)
Separating DNAIn gel electrophoresis, ______ ________________ are placed at one end of a porous gel, and an electric voltage is applied to the gel. When the power is turned on, the negatively charged DNA molecules move toward the ________ end of the gel. Gel electrophoresis can be used to _____________ the ________________ of different organisms or different individuals. It can also be used to _________ and __________ one particular gene in an individual's genome.
![Page 118: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/118.jpg)
1) _______________ _____________ cut DNA into fragments.2) The DNA fragments are poured into ________ on a gel.3) An electric voltage is applied to the gel. This moves the ______ ______________ across the gel.The smaller the DNA fragment, the faster and farther it will move across the gel.4) Based on size, the DNA fragments make a _________ __ ___________ on the gel.5) These bands can then be ______________ with other samples of DNA.
![Page 119: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/119.jpg)
Using the DNA Sequence
Knowing the sequence of an organism’s DNA allows researchers to study specific genes, to compare them with the genes of other organisms, and to try to discover the functions of different genes and gene combinations
![Page 120: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/120.jpg)
Reading the SequenceIn DNA sequencing, a complementary DNA strand is made using a small proportion of fluorescently labeled nucleotides.
![Page 121: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/121.jpg)
Each time a labeled nucleotide is added, it stops the process of replication, producing a short color-coded DNA fragment.
![Page 122: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/122.jpg)
When the mixture of fragments is separated on a gel, the DNA sequence can be read.
![Page 123: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/123.jpg)
Cutting and PastingGene splicing
Short sequences of DNA can be assembled using DNA synthesizers. “Synthetic” sequences can be joined to “natural” sequences using enzymes that splice DNA together.
![Page 124: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/124.jpg)
These enzymes also make it possible to take a gene from one organism and attach it to the DNA of another organism. Such DNA molecules are sometimes called recombinant DNA.
JellycatsLemid?
Jellyfish glow gene
![Page 125: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/125.jpg)
Making Copies
Polymerase chain reaction (PCR) is a technique that allows biologists to make copies of genes.
A biologist adds short pieces of DNA that are complementary to portions of the sequence.
![Page 126: Topic 3 Genetics asexual reproduction – only one parent, reproduction by mitosis or Binary fission](https://reader036.vdocuments.net/reader036/viewer/2022062308/56649d0a5503460f949dc87a/html5/thumbnails/126.jpg)
1) DNA is heated to separate its two strands, then cooled to allow the primers to bind to single-stranded DNA.
2) An enzyme called DNA polymerase starts making copies of the region between the primers.