Download - Genetics
![Page 1: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/1.jpg)
GENETICSBiology
Chapter 10-12
![Page 2: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/2.jpg)
![Page 3: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/3.jpg)
![Page 4: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/4.jpg)
Gregor Mendel- the Father of GeneticsAustrian monkworked in gardens in monastery
studied pea plants
studied heredity- passing on of traits or characteristics from parents to offspring
![Page 5: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/5.jpg)
genetics – the branch of biology that studies heredity
traits- characteristics that are inherited
gametes- sex cells; sperm and egg cells
![Page 6: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/6.jpg)
fertilization- when sperm unites with egg cell forming a 1 celled structure called a zygote
in plants, achieved thru pollination
![Page 7: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/7.jpg)
2 types of reproduction:1. Asexual reproduction- when there is
NO exchange of genetic information between organismsex: mitosis in paramecium
2. sexual reproduction- where there is an exchange of genetic info between orgex: meiosis
![Page 8: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/8.jpg)
in unicellular organisms, MITOSIS is form of asexual reproductionwon’t go thru MEIOSIS
in multicellular organisms, (plants, animals, us, etc) MITOSIS is how more cells are formedMEIOSIS is how sperm & egg cells
are formed
![Page 9: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/9.jpg)
on chromosomes, there are segments that code for specific traits; segments are called GENES
genes are the factors that offspring have received from mom & dad
![Page 10: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/10.jpg)
chromatid
SISTER CHROMATIDS
chromosome
child receives one chromosome from mom and one fromdad for each DNAmolecule in species
![Page 11: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/11.jpg)
genes code for traitstraits are characteristics
that are inherited alleles- alternate forms
of genes
![Page 12: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/12.jpg)
receive 1 allele from mom & 1 allele from dad for each trait
represent alleles by using LETTERS
dominant allele is represented by a CAPITAL LETTER
represents the trait that is stronger or dominant
(usually will use the 1st letter of the dominant trait)
![Page 13: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/13.jpg)
for ex: rolling tongue is a dominant trait in humans
usually use R to represent ability to roll tongue
![Page 14: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/14.jpg)
recessive alleles are represented by a small letter
represents the weaker or hidden trait
![Page 15: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/15.jpg)
for example, not being able to roll your tongue is a recessive trait
represented by r
![Page 16: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/16.jpg)
terms we have to learn:
phenotype- physical appearance of the trait in the organism
![Page 17: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/17.jpg)
genotype- gene or allele combination of an organism for that traitex: RR or Rr or rr
got 1 from mom; 1 from daduse the combo of letters to represent genotype
![Page 18: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/18.jpg)
more terms to learn: homozygous dominant-
means 2 capital letters (dominant trait)
homo= same aka: pure dominant for ex: RR= can roll tongue
![Page 19: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/19.jpg)
homozygous recessive- 2 little letters ( 2 recessive alleles)
aka: pure recessive for ex: rr = can’t roll tongue
![Page 20: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/20.jpg)
heterozygous- have 1 capital letter (dominant trait) & 1 little letter (recessive trait)
hetero= different (means size here or trait)
aka: hybrid
for ex: Rr What does this genotype mean?
can roll tongue Why?
![Page 21: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/21.jpg)
Dominant: L k e M r O d S E Recessive: Mp Q t r D K n s Homozygous Dominant: BB Hh gg TT Rr Homozygous Recessive: ff Aa Cc tt KK Ll mm
![Page 22: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/22.jpg)
Offspring combinations in which dominant trait must show:BB Dd ee Jj Rr ii
Offspring combinations in which recessive phenotype must show:Ee ff Hh ii Ll nn Oo
![Page 23: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/23.jpg)
Dominant: L k e M r O d S E Recessive: M p Q t r D K n
s Homozygous Dominant: BB Hh gg TT Rr Homozygous Recessive: ff Aa Cc tt KK Ll mm
![Page 24: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/24.jpg)
Offspring combinations in which dominant trait must show:BB Dd ee Jj Rr ii
Offspring combinations in which recessive phenotype must show:Ee ff Hh ii Ll nn Oo
![Page 25: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/25.jpg)
to figure out traits organisms inherit:
use a Punnett square perform monohybrid crosses use a 4 box square
![Page 26: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/26.jpg)
![Page 27: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/27.jpg)
Karotype
![Page 28: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/28.jpg)
![Page 29: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/29.jpg)
Meiosis in multicellular org, there are 2 types of
cells:1. body cells (somatic) stomach, bone,
nervous, etc2. sex cells (gametes)- sperm, egg
inside somatic cells, you’ll find 2 of each kind of chromosome= DIPLOID (2n)
inside sex cells, you’ll find only 1 of each kind of chromosome= HAPLOID (n)
![Page 30: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/30.jpg)
chromosomes occur in pairs called homologous chromosomeshave genes for the same traits located in the same positions
they are not genetically identical (we got 1 from mom, 1 from dad)
![Page 31: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/31.jpg)
![Page 32: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/32.jpg)
we have 23 pairs of these homologous chromosomes
somatic cells (body) have 46 chromosomes in them
in sex cells (sperm or egg) we have just 23 chromosomesthis is IMPORTANT WHY?
![Page 33: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/33.jpg)
different organisms have different numbers of chromosomes in their cells
look p. 265
chromosome # does NOT indicate complexity
if an org has 24 chromosomes in its body cells, how many chromosomes will be in the sex cells?
![Page 34: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/34.jpg)
What would happen in humans if the sperm and egg cells each contained 46 chromosomes?
the resulting zygote would have 92
SOMETHING has to occur to prevent too many chromosomes
Meiosis- process of nuclear division that reduces chromosome # by half
![Page 35: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/35.jpg)
![Page 36: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/36.jpg)
meiosis is involved in sexual reproduction
results in haploid cells – makes sperm & egg cells
in order to happen, there has to be 2 nuclear divisions
![Page 37: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/37.jpg)
similar to mitosis, but divides twice
divided into Meiosis I & Meiosis IIsame names as mitosis (easier)
Interphase-chromosomes are replicated, but aren’t visible yet
![Page 38: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/38.jpg)
Prophase I chromosomes
become visible nucleus/ nucleolus
disapppears UNIQUE to meiosis:
homologous chromosomes form TETRAD
chromatids are paired tightly; genetic material is exchanged= CROSSING OVER
![Page 39: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/39.jpg)
![Page 40: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/40.jpg)
Metaphase I tetrads line
up at equator (middle)
UNIQUE:homo chromos are lined up as PAIRS
![Page 41: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/41.jpg)
Anaphase I homo chromos
separate & move to opposite ends of cell
UNIQUE: centromeres do NOT split- this ensures that each new cell only receives ONE chromosome from each parent
![Page 42: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/42.jpg)
Telophase I spindles break down
chromosomes uncoil cytoplasm divides to 2
cells each new cell has ½
genetic info of parent cell
another division must occur because chromosomes were copied
![Page 43: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/43.jpg)
Prophase II new spindle
fibers form chromosom
es are visible again
![Page 44: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/44.jpg)
Metaphase II chromosom
es line up individually at middle of cell
![Page 45: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/45.jpg)
Anaphase II centromeres
split sister
chromatids separate & move to opposite ends of cell
![Page 46: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/46.jpg)
Telophase II
spindles break down
nuclei reforms
cytoplasm divides
![Page 47: Genetics](https://reader036.vdocuments.net/reader036/viewer/2022062520/56816452550346895dd61d46/html5/thumbnails/47.jpg)
Results of meiosis 4 haploid cells formed from
original diploid cell
they become gametes- sperm and egg cells