EOC REVIEW

DNA, RNA, Replication, Transcription and Translation

DNA/RNA

Carry genetic information All organisms share the same genetic code (nitrogenous bases) Made of a chain of nucleotides Nucleotides contain a sugar, phosphate, and a nitrogen base The sugars and phosphates link to make the sugar phosphate backbone and the Nitrogen bases are held in the

middle by hydrogen bonds

Review Questions

1. In DNA, what does Adenine pair with? Thymine

2. In DNA, what does Cytosine pair with? Guanine

3. What three things do nucleotides contain? Sugar, Phosphate and nitrogen base

4. What is the sugar called in RNA? Ribose

5. What is the sugar called in DNA? Deoxyribose

Replication

Occurs in Interphase’s s phase Replication occurs in both directions The process used by cells to copy DNA, making an identical strand of DNA Enzyme unzips DNA and each side of the ladder, and acts as a template for the building of the complementary

strando Use the Nitrogen Base Pairing Rules

A-T, C-G TACGGAC (old strand) ATGCCTG (new strand)

Codon

Sequence of three mRNA nucleotides that code for an amino acid

DNA RNA

Double stranded/helix Single stranded/helix Sugar is deoxyribose Sugar is ribose Remains in the nucleus Can leave the nucleus Codes for proteins/RNA Copy of DNA information Four Base Pairs: ATCG Four Base Pairs: AUCG

o Adenine Adenineo Thymine Uracilo Guanine Cytosineo Cytosine Guanine

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Transcription

The process of making RNA from DNA DNA> mRNA (occurs in the nucleus)

o TACGGAC (template DNA strand)o AUGCCUG (RNA Built)

1. RNA polymerase binds to and separates the DNA strands at promoter siteso Promoter- 3 base sequence that serves as a starting and ending points for RNA to be made.

2. RNA polymerase uses one strand of DNA as a template to make the complementary strand of DNA Three types of RNA have a role in protein synthesis

o 1. mRNA- messenger: blueprint for how to build proteino 2. tRNA-transfer: carries amino acids from the cytoplasm to the ribosomeso 3. rRNA-ribosomal: makes up a ribosome, where protein is made

Review Questions

1. What does semi conservative mean?The replicated copy of DNA has one new side and one Old side

2. How many nucleotides code for an amino acid? 3

3. What is the process of making RNA from DNA?Transcription

Translation

The process of building a protein by matching codons in mRNA to anticodons of tRNA (use codon chart)

o mRNA>protein (occurs on ribosomes) 1. mRNA attaches to a ribosome 2. Starting at codon “AUG”, ribosome reads each codon

o Codon= 3 nucleotides 3. For each codon, an amino acid is brought into the ribosome by tRNA

o Each tRNA molecule carries only one kind of amino acido Each tRNA has the anticodon, that is complementary to one mRNa codon

4. A peptide bond forms between each amino acid as it is brought into the ribosome> polypeptide chain 5. tRNA is released 6. Polypeptide chain stops growing when the ribosome reaches a stop codon on the mRNA Polypeptide (protein) & mRNA are released from the ribosome Reminders:

o 3 nucleotides= 1 codon=1 amino acido 20 different amino acidso Proteins are determined by the sequence of amino acids

Review Questions

1. What are the segments of DNA that code for proteins or traits? Exons, codons, genes

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2. What is the process of making RNA from DNA? transcription3. How many different amino acids are there?

20 1. What is the 1st step in protein synthesis?

transcription2. What is the 2nd step in protein synthesis?

translation3. What is mRNA>proteins at the ribosome?

translation4. What is converting DNA>mRNA in the nucleus?

Transcription5. Which of these changes to the DNA triplet TCG will affect a protein produced?

a. AGT b. TCA c. TCC d. AGA

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Cell Division General

Haploid – having one set of chromosomes (n) – gametes – sperm/egg

Diploid – having two sets of chromosomes (2n) – body cells – one set is maternal and one is paternal

Plants cells do not have centrioles to do cell division

Steps to cell Division

Interphase

Cell spends most of its time = resting phase

Steps

1. G1- cell grows

2. S – DNA is synthesized

3. G2- all other organelles are copied

Steps of Mitosis

1. Prophase- nuclear membrane breaks down

2. Metaphase chromatids line up in the middle

3. Anaphase- sister chromatids are pulled apart

4. Telophase- plants = cell plate

animals = cleavage furrow

Cytokinesis- separation of cell (not a step of mitosis)

*** asexual reproduction – a type of reproduction that only involves one parent cell. Daughter cells look identical to the parent cell. Examples include: Mitosis, Binary fission in bacteria, cloning, regeneration, and budding.

Advantage – quicker, requires less energy, mass production

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Disadvantage – less variation, no genetic diversity, more difficult to evolve

REVIEW QUESTIONS

1. When does the replication of DNA occur? What is this phase called?

S phase of Interphase

2. What happens during G1 and G2?

G1- cell grows G2- organelles are copied and the nucleus prepares to divide

3. What stage does the cell spend most of its life in? _______Interphase____________

4. What does the cell do during this time?

G1- cell grows G2- organelles are copied and the nucleus prepares to divide S- DNA replicates

Mitosis Overview

Produces two identical diploid daughter cells

Occurs in body cells to grow and repair

DNA coils to form chromosomes during cell division

Cancer / mutations

• Caused when mitosis/cell cycle cannot be stopped• Mass accumulation of cells none as a tumor• There is an error somewhere in replication, transcription, translation• Cannot be passed from parent to offspring unless located on the gametes (egg or sperm)

5. Put the following stages of mitosis (cell division) in order. Then Name them.

1st: ___C________ called ____Interphase_______

2nd: ___B________ called ____Prophase

3rd: ___E________ called _____Metaphase

4th: ___A________ called _____Anaphase

5th: ____D_______ called Telophase/ Cytokinesis

6. How many chromosomes do humans have in their… Body cells? ___46_____

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Goal 3: Learner will develop an understanding of the continuity of life and the changes of organisms over time. 30-35%

3.01: Analyze the molecular basis of heredity including: DNA replication, Protein Synthesis (transcription and translation), and gene regulation.

1. Below is a strand of DNA. (Chapter 12) DNA in the cells exists as a double helix – what needs to be added to it to make it a double helix? Give the complementary nucleotide sequence. __C___ _T____G_ __G____ _C_____T ______ ______

2. Describe the structure of DNA. What are the black pentagons? _Deoxyrobose, a 5 carbon sugar__________ What are the nitrogen bases? __adenine, thymine cytosine and guanine__________ What weak bonds hold the complementary bases together? __hydrogen_Bonds____

3. If the strand of DNA above undergoes transcription, what will the sequence of the mRNA be? __GUGGCU

4. After translation, what would the amino acid sequence be for this section of mRNA? (read from right to left)

___valine, alanine_______________________________________________________

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5. What is a codon? A triplet of RNA nucleotides that codes for a specific amino acid

6. Compare RNA and DNA in the following table.

RNA DNA

Sugars ribose deoxyribose

Bases Guanine, cytosine, adenine and uracil

Guanine, cytosine, adenine and thymine

Strands single double

Where

In Cell

cytoplasm nucleus

Function Codes for proteins Carries all genetic information

7. What kind of bond holds the amino acids together in the protein that is formed? ___peptide___

8. What are the three types of RNA and what are their functions?

1) ___messenger RNA carries code from DNA to ribosomes__________________________________

2) ___transfer RNA transfers amino acids to the ribosomes_________________________________

3) _____site of translation , it IS the ribosome_____________________

9. What kind of weak bonds hold the two strands of DNA together? ______hydrogen__________________

10. Why is it important that these bonds be weak? So that they can “unzip” for replication and making mRNA

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11. Describe the process of DNA replication. What enzyme breaks apart the hydrogen bonds between bases? ________DNA Helicase__________________

How many pieces of DNA are made? ___2_____ What does semi-conservative mean? One side of copied strand is the original and the other side is a new strand

12. Describe the process of protein synthesis: What is transcription? DNA copies its code onto mRNA

13. What is translation? Coding for specific amino acids

14. What happens to DNA when a mutation occurs? A base sequence changes

15. How does this affect the mRNA? mRNA will also change accordingly

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16. How can this affect translation? It might code for a different amino acid OR it might not

17. How does this affect the structure and shape of the resulting protein? _

it might change the protein or shorten the amino acid chain___________

Cell Cycle

Look at the diagram of the cell cycle.

18. When does the replication of DNA occur? What is this phase called?

S phase of interphase

19. What do GI and G2 represent?

Growth phases

20. What stage does the cell spend most of its life in? ___interphase________________

What does the cell do during this time? Grows, replicates and goes about the general cell business

21. Does mitosis include cytokinesis (division of the cytoplasm)? (Y/N?)

no

Gene Expression and Regulation

22. In the diagram to the left, what is the role of the RNA polymerase?

Causes the RNA to attach to DNA

23. What is the role of the repressor? Stop RNA polymerase from attaching RNA to DNA

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24. The gene codes for lactase, an enzyme that digests milk sugar (lactose).

25. When lactose is present what happens to the repressor?

Stops working

26. When the repressor does not attach to the repressor region of the gene, what happens to gene expression?

Lactase is formed

27. If all the cells in an organism (cells with nuclei) have the same DNA, explain, in terms of genes, how a nerve cell functions differently from a muscle cell. Nerve cells are coded genetically to be long and sensitive to electrical stimuli in order to carry messages

28. Why do pancreas cells produce insulin in great amounts but blood cells does not? Blood cells have other jobs and are genetically coded for them

29. What is cancer? What are some causes of cancer? Rapidly growing cells. The cell cycle is not checked

3.02 Compare and contrast the characteristics of asexual and sexual reproduction.

30-31. Complete the following Chart of Mitosis and Meiosis.

MITOSIS MEIOSIS

Type of reproduction

(Asexual or sexual)

Asexual Sexual

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Chromosome number of mother cell (1N=haploid or 2N=diploid)

Diploid Diploid

Chromosome number of daughter cells (1N=haploid or 2N=diploid)

Diploid Haploid

Number of cell divisions One Two

Number of cells produced Two Four

When does replication happen? Growing and developing or repair Reproduction only

SOURCES OF VARIATION Mutations only Crossing over

Crossing over No Yes

33. How many chromosomes do humans have in their… Body cells? _46_______ Sex cells? ____23______

34. What does Diploid mean? 2n number of chromosomes

35. What does Haploid mean?1n number of chromosomes

36. When does crossing over occur during Meiosis? _____prophase I________________________

37. What is the major focus of Meiosis I? ______________Crossing Over___________________________________

38. What is the major focus of Meiosis II? ________________Cell division into gametes__________________________