DNA & Protein Sythesis

Question 1

What is a mutation?

Answer 1

A change in DNA

Question 2

What 3 molecules were thought to be possibilities for being the genetic material?

Answer 2

Proteins, RNA, or DNA

Question 3

What happened to Griffith’s mice when R cells were injected into them?

Answer 3

Lived

Question 4

What happened to Griffith’s mice when S cells were injected into them?

Answer 4

Died

Question 5

What happened when dead S cells, along with live R cells were injected into Griffith’s mice?

Answer 5

Died

Question 6

What kind of cells are found in the blood of mice when dead S cells, live R cells, and DNAase are injected?

Answer 6

Live R Cells

Question 7

What kind of cells are found in the blood of mice when dead S cells, live R cells, and RNAase are injected?

Answer 7

Live S cells

Question 8

What kind of cells are found in the blood of mice when dead S cells, live R cells, and Protease are injected?

Answer 8

Live S cells

Question 9

If one strand of DNA has the following sequence of nucleotides, what would the other strand look like? GCCTAAGCCTA

Answer 9

CGGATTCGGAT

Question 10

What are the monomers of DNA and what is one of these units made of?

Answer 10

Nucleotide is made of a phosphate group, 5 carbon sugar (deoxyribose), & a nitrogenous base

Question 11

Name the 4 nitrogen containing bases

Answer 11

Adenine, Guanine, Thymine, Cytosine

Question 12

Who officially discovered the helical structure of DNA?

Answer 12

Watson and Crick

Question 13

What makes up the backbone of DNA?

Answer 13

Sugar and Phosphate

Question 14

What makes up the rungs of DNA?

Answer 14

Nitrogenous Bases

Question 15

What always joins with Adenine in DNA?

Answer 15

Thymine

Question 16

What always joins with Cytosine?

Answer 16

Guanine

Question 17

What holds the 2 strands of DNA together (they are found between bases that are paired together).

Answer 17

Hydrogen Bonds

Question 18

Briefly describe DNA replication (ensure to include ALL enzymes involved).

Answer 18

Helicase (an enzyme): unzips and untwists DNA, separating DNA into two complimentary “ parent strands”. This happens at many “origins of replication” along a chromosome

Single-stranded Binding Protein: attach to each separate parent strand & stabilize them Each parent strand can now act as a template for new complimentary “daugher strands”.

Primase (an enzyme): adds a short sequence of complimentary RNA to the DNA. This short piece of RNA is called a Primer.

Topoisomerase: as helicase unwinds DNA, pressure builds up where DNA is unwinding. Topoisomerase relieves this pressure by breaking DNA, swivelling it, and re-joining it

Question 19

Problem with DNA Polymerase III only being able to add to the 3’ end of the growing piece of DNA?

Answer 19

DNA is antiparallel which means that DNA polymerase III can only add nucleotides to one strand continuously. (Leading Strand)

The other strand needs to have little short pieces of DNA at a time. This strand is called the (Lagging Strand). These pieces of DNA are called Okazaki Fragments

Question 20

Formation of Okazaki Fragments:

Answer 20

RNA Primase adds RNA primers to start fragments

DNA Polymerase III adds nucleotides to the 3’ end of the RNA primers

DNA Polyermase I replaces the RNA primers with DNA

Ligase attaches the last nucleotide of each fragment to the next one (It glues the fragments together)

Question 21

What is a replication fork?

Answer 21

Where DNA synthesis begins.

Question 22

What is a point mutation?

Answer 22

A mutation involving 1 or few nucleotides

Question 23

What kinds of point mutations are there?

Answer 23

Substitutions; Insertions & Deletions

Question 24

What kind of mutation is considered to be a “frameshift” mutation?

Answer 24

Insertions and deletions

Question 25

List the types of chromosomal mutations that exist & briefly explain what each one is

Answer 25

Deletion – part of chr omosome is deleted

Duplication – chromosome is duplicated

Inversion – part of chromosome is reversed

Translocation – part of chromosome breaks off & attaches to another chromosome

Question 26

State 3 differences between DNA & RNA

Answer 26

DNA has deoxyribose, RNA has ribose

DNA has 2 strands, RNA has 1 strand

DNA has thymine, RNA has uracil

Question 27

If a coding strand of DNA is 18 - nucleotides, & all 18 nucleotides are transcribed into mRNA:

How many codons will be in the mRNA?

How many amino acids will be in the resulting protein (assuming that the first 3 nucleotides in the m RNA formed are AUG)

Answer 27

6

6

Question 28

What’s the function of mRNA?

Answer 28

To take a copy of the genetic code of a gene out of the nucleus to ribosomes (takes copy of DNA to ribosomes)

Question 29

What’s the function of tRNA?

Answer 29

To match proper amino acids with appropriate codons on mRNA

Question 30

What’s a codon?

Answer 30

3 bases on mRNA that encode for a specific amino acid

Question 31

What’s an anticodon?

Answer 31

The 3 bases on tRNA that match up with a codon

Question 32

Briefly describe the process of transcription.

Answer 32

RNA polymerase binds to the initiation site on DNA (a specific sequence of bases). RNA polymerase separates DNA and uses one of the 2 strands as a template to make a single strand of mRNA. When the terminator of the gene is reached (specific sequence of bases on DNA) then RNA polymerase falls off & so does the mRNA. The mRNA then leaves the nucleus through nuclear pores.

Question 33

Briefly describe the process of translation (Include what happens at the different sites found on the ribosomal subunits).

Answer 33

A small & large ribosomal subunit bind at the AUG (start) condon on mRNA. The tRNA with methionine attaches at the P site of the ribsome. Next a tRNA with the proper amino acid and anticodon that fits with the next codon on mRNA attaches at the A site. Whatever amino acids are in the P site hop onto the new amino acid that just came into the A site. The ribosome then moves up the mRNA 3 base knocking the now empty tRNA that had methione out and it opens up the A site, because what WAS in the A site is now in the P site. The process continues until a stop codon is reached. Remember….tRNA with new amino acids come in at the A site and whatever amino acids were already in the P site hop onto the new amino acids that come in at the A site.

Question 34

Do Matching and Column Filling on Edline.

Answer 34

Check Answers on Edline.