Warm Up1. Write the equation for photosynthesis

2. Write the equation for aerobic cellular respiration.

3. In what organelle does photosynthesis occur? In what organelle does respiration occur?

4. How are prokaryotic cells different from eukaryotic cells?

5. Give an example of a prokaryotic cell. Give an example of an eukaryotic cell.

Genetics Part IHistory of DNA:

Discovered by: James Watson, Francis Crick, Maurice Wilkins, and Rosiland Franklin

Franklin and Wilkins discovered there was DNA.

Watson and Crick discovered the molecular shape.

Structure of DNA

Structure of DNA

• “Twisted ladder”

• Sides of ladder are alternating sugar-phosphate groups

• “Rungs” are complementary nitrogenous bases that are joined together by hydrogen bonds

Structure of DNA•Nucleotide (SUBUNIT) is:

-1 sugar (deoxyribose), 1 phosphate and 1 nitrogen base.

•Why are they so important?-In DNA they code for proteins, which is the central key to cell function and life

“Rungs” or Nitrogen Bases

• Adenine=A

• Thymine=T

• Cytosine=C

• Guanine=G

• A bonds with T

• G bonds with C

Structure of DNA• Two nucleotides bond at the nitrogenous

base and form a double helix. This double helix twists on itself to give it the characteristic shape.

• DNA looks like a ladder in that the sugar-phosphate is termed the ‘backbone’ (on outside) and the nitrogenous bases are termed ‘rungs’ (on inside).

Structure of DNA• The bases are connected to a complimentary

strand by hydrogen bonding between paired bases, adenine (A) with thymine (T) and guanine (G) with cytosine (C)

• A and T are connected by two hydrogen bonds while G and C are connected by three

• The hydrogen bonds are very, very, very weak. They need to be weak so that the DNA can separate in order for replication.

Warm Up1. What is DNA? What can the name tell you?

2. What are the 3 parts of a nucleotide?

3. What are the names of the four nitrogenous bases?

4. What base pairs with G? What base pairs with A?

5. What is the “backbone” of a DNA molecule? What are the “rungs” of a DNA molecule?

ASEXUAL CELL CYCLE

Asexual Reproduction -one ‘parent cell’ is needed-offspring are genetically similar to

the parent-Cells do this anytime a

“replacement” is needed-Mitosis occurs (will review!)

Cell cycle

4 phases

1.G1: Gap 1

2.S: Synthesis

3.G2: Gap 2

4.M: Mitosis

Cell Cycle Cont’d

• G1, S, and G2 make up the largest portion of the cycle and are collectively called INTERPHASE

• Sometimes cells temporarily or permanently stop dividing. If this occurs they are said to be in the G0 phase (Gap 0) or RESTING phase

G0- GAP 0

1. Cell exits the cell cycle

2. Cell no longer divides

3. Examples: neuron, red blood cell, sperm, unfertilized egg

G1- GAP 1

1. Cell increases in size

2. Cell produces RNA and proteins to prepare the DNA to replicate.

S=Synthesis DNA Replication

1. An exact copy is made

2. Enzymes (proteins) work to link nucleotides together.

Steps to DNA Replication:-Helicase splits at the hydrogen bonds (remember they are very weak).

-Another enzyme brings individual nucleotides to leading strand. (top down)

-Another enzyme brings nucleotides to the lagging strand. (bottom up)

-End result: a chromosome.

Parts of a chromosome

Centromere

Sister chromatids

What is a chromosome?

• Tightly coiled DNA and the proteins associated with DNA

• Why? Allows large amounts of DNA to fit into the nucleus.

Function of the different parts of a chromosome

Centromere- holds sister chromatids together until they need to separate for replication.Sister chromatids- contain the same genetic information. Separate so exact copies can be made when producing an identical cell.

G2- GAP 2

1. Continue to produce proteins and grow

2. Determines if the cell is prepared for M… if not, it will fix problems.

Mitosis

• After G2, cell may be ready to undergo mitosis-the actual dividing of a cell.

• You MUST memorize the characteristics during each stage of mitosis!

• Mitosis PPT

Warm Up1. During what phase of mitosis does the

nuclear envelope disappear?

2. During what phase do the sister chromatids pull apart and go to opposite ends of the cell?

3. During what phase is DNA replicated?

4. During what phase would the DNA first appear as chromosomes?

5. During what phase do the spindle fibers begin to form?

PROTEIN SYNTHESIS

DNA -vs- RNADNA

-Deoxyribose-Thymine-Double Helix

RNA-ribose-Uracil-single twisted strand

Both-Nucleic acid-Nucleotides: C, G, A

Protein Synthesis

• The process of taking DNA and bringing the “chemical code” to life. We do this by making proteins that we need to carry out life-sustaining processes.

• Two key steps:– Transcription– Translation

Protein Synthesis1. Transcription

-mRNA (messenger RNA) is TRANSCRIBED

-Take the DNA single strand and add complimentary base pairs except RNA format-uracil (U) instead of thymine (T)

-Occurs inside the nucleus

Terminology for Translation• Codon:A sequence of three nucleotides

located on the mRNA

• Anticodon:A sequence of three adjacent nucleotides located on one end of the tRNA molecule

2. Translation

-Occurs inside a ribosome.

-Codon on mRNA that will match the anticodon on the tRNA

-tRNA links the anticodon to the codon

-tRNA has an amino acid attached-determined by codon. As codon/anticodon is matched amino acids are bound together by means of a peptide bond

-Linking amino acids together forms a polypeptide chain, which is folded into proteins.

Matching codons to amino acids• Use chart.

• Find codon-look up amino acid.

• Practice problems in packet are for homework.

Why do we need Protein Synthesis?

• Make proteins- chain of amino acids.

• We need proteins for growth and development of cells

• More specifically, we need polypeptide chains (proteins) with a specific code so it can do a specific job within our body

Few more things about protein synthesis:

1. DNA can never leave the nucleus

2. Transcription occurs in the nucleus

3. Translation occurs at the ribosome (in cytoplasm)

4. There is always a ‘start’ message (AUG) and a ‘stop’ message (UGA).

-start gets the ribosome working

-stop lets the ribosome release the polypeptide chain.

Protein Synthesis Video

http://www.youtube.com/watch?v=NJxobgkPEAo

Warm Up1. Write the equation for photosynthesis.

2. Write the equation for aerobic respiration.

3. What type of mutation?

CCTGAG into CCTAAG

4. What type of mutation?

CCTGAG into CTGAG

5. What type of mutation?

CCTGAG into CCTGATG

Protein Synthesis ActivityRoles (mRNA, ribosome, tRNA):

1. mRNA- go to the nucleus and write the compliment to the DNA code

2. Ribosome- receive the mRNA message, write down the tRNA anticodons, determine amino acids based on chart, tell tRNA what anticodons to locate on cabinets.

3. tRNA- receive the anticodon from the ribosome and locate it; flip the card over and read the word; bring the word to the ribosome so that they can write the word down.

Protein Synthesis ActivitySummary: EACH PERSON MUST

COMPLETE THIS!!!

1. What does each word represent?

2. What does the sentence represent?

3. What happened if you wrote down the wrong mRNA code based on the DNA?

4. What happened if you wrote down the wrong tRNA code based on the mRNA?

5. Summarize how making a sentence is similar to protein synthesis.

Some animations on the web

http://www.cns.pdx.edu/~newmanl/ChapterOutlines/Chapter01.html

http://www.ai.mit.edu/lab/olympics/98/events/MITosis/

Warm Up

1. What are the monomers of DNA?

2. Transcribe:

ATC-GCC-TAA-ACT

3. Translate:

UGC-ACU-GGU-UAC

4. Where does transcription occur?

5. Where does translation occur?

MUTATIONS

What is it?

• Accidental changes in a sequence of DNA

• Can prevent a gene from functioning properly or completely

MutationTypes:

1. Substitution- a mutation that exchanges one base for another

a mutation that exchanges one base for another

                         

                  

- Can cause a small change in the protein produced or nothing at all will happen.

Mutation2. Insertion- mutations in which extra base

pairs are inserted into a new place in the DNA

-Can lead to added amino acids in polypeptide chain

Mutation3. Deletion- mutations in which a section of

DNA is lost, or deleted

                         

                 

-Can lead to missing amino acids in polypeptide chain

What causes mutations?• Spontaneous/random

• Radiation or chemical exposure

Radiation

• Overexposure to radiation creates an excess of energy which causes the bases to pair incorrectly—creating mutations

Why does radiation cause cancer?

• Cancer: The disease caused by an uncontrolled division of abnormal cells in a part of the body.

• Why does radiation cause cancer?– Mutations ultimately create an error in the DNA

blueprint. If the DNA is wrong, it causes the cell to lose control of cell division. When cells begin to divide rapidly, it creates a tumor.

Advantages and Disadvantages of errors in protein synthesis

• Advantages: an overproduction in proteins can be helpful if you have an injury and need rapid repair

• Disadvantages: an overproduction in proteins can cause cancer. An underproduction in proteins can cause genetic disorders