DNA Replication

Question 1

Allows genetic information to be inherited from a parent cell to daughter cells (by mitosis) and from generation to generation (starting with meiosis)

Answer 1

DNA replication

Question 2

Where the replication of chromosomal DNA begins

Answer 2

Origins of Replication (ORI)

Question 3

Unwinds and separates the parental DNA strands

Answer 3

Helicase

Question 4

• Each nucleotide is bounded by a _________ which keeps the strands from re-healing (coming back together)
• Stabilizes the unwound parental strands

Answer 4

Single-stranded Binding Protein

Question 5

An enzyme that helps relieve the strain of the double helix by breaking, swiveling, and rejoining DNA strands.

Answer 5

Topoisomerase

Question 6

At each end of a replication bubble is a _______ ____, a Y-shaped region where the parental strands of DNA are being unwound.

Answer 6

Replication fork

Question 7

Synthesizes RNA primers, using the parental DNA as template

Answer 7

Primase

Question 8

An initial nucleotide chain that can be used as a pre-existing chain that is produced during DNA synthesis (short stretch of RNA)

Answer 8

Primer

Question 9

New strand that DNA strands encode

Answer 9

“leading strand”

Question 10

Lays the leading strand continuously and moves toward the helicase

Answer 10

DNA Polymerase III

Question 11

other new strand that the other DNA strand which runs in the opposite direction encodes

Answer 11

“lagging strand”

Question 12

formed when the DNA pol III adds DNA nucleotides to the primer

Answer 12

Okazaki fragment 1

Question 13

forms a bond between the newest DNA and the DNA of fragment 1 (links the two Okazaki fragments together)

Answer 13

DNA ligase

Question 14

replace the RNA primer (between the two Okazaki fragments) with DNA

Answer 14

DNA Polymerase I

Question 15

using parental DNA as a template, synthesizes new DNA strand by adding nucleotides to an RNA primer or a pre-existing DNA strand

Answer 15

DNA polymerase III

Question 16

other enzymes remove and replace incorrectly paired nucleotides that have resulted from replication errors

Answer 16

mismatch repair

Question 17

DNA-cutting enzyme

Answer 17

Nuclease

Question 18

every double helix in the new generation of an organism consists of one complete “old” strand and one complete “new” strand wrapped around each other.

Answer 18

Semiconservative

Question 19

Synthesis in __ to __ direction

Answer 19

5’ to 3’

Question 20

a large protein complex that carries out DNA replication, starting at the replication origin.

Answer 20

replisome

Question 21

Models of DNA Replication

Answer 21

1. Conservative Model
2. Semiconservative Model
3. Dispersive Model

Question 22

• Only transcribes rRNA genes
• Makes ribosomes

Answer 22

RNA polymerase 1

Question 23

Transcribes genes into mRNA (messenger)

Answer 23

RNA polymerase 2

Question 24

Only transcribes tRNA (transfer) genes

Answer 24

RNA polymerase 3

Question 25

Building mRNA

Answer 25

1. Initiation 2. Elongation 3. Termination

Question 26

Assembly of initiation complex

Answer 26

Initiation

Question 27

Adding N-bases bases

Answer 27

Elongation

Question 28

two types of termination in building mRNA

Answer 28

1. Rho-dependent 2. Rho-independent

Question 29

- Protein factor Rho - Rho protein will go after the RNA polymerase and detach it from the template.

Answer 29

Rho-dependent

Question 30

RNA polymerase encounters a GC sequence that has a triple bond

Answer 30

Rho-independent (GC-rich)

Question 31

Eukaryotic mRNA need work after transcription

Answer 31

Primary transcript (pre-mRNA)

Question 32

- mRNA splicing = edit out introns - Protect mRNA from enzymes in cytoplasm - Add 5’ cap - Add polyA tail

Answer 32

mRNA processing (making mature mRNA)

Question 33

non coding (inbetween) sequences

Answer 33

Introns

Question 34

coding (expressed) sequences

Answer 34

Exons

Question 35

- Proteins - Fold the intron and cut them out of the mRNA

Answer 35

Small nuclear ribonucleoproteins

Question 36

- Several snRNPS - Recognize splice site sequence - Cut and paste

Answer 36

Spliceosome

Question 37

Prokaryote vs. Eukaryote genes

Answer 37

Prokaryote - DNA in cytoplasm - Circular chromosome - Naked DNA - No introns Eukaryote - DNA in nucleus - Linear chromosomes - DNA wound on histone proteins - Introns vs. exons

Question 38

- Triplet of bases - Blocks of 3 nucleotides decoded into the sequence of amino acids

Answer 38

Codons

Question 39

Translation in Prokaryotes

Answer 39

Bacterial chromosome > transcription > mature mRNA > translation > protein

Question 40

Transcription and translation are simultaneous in bacteria

Answer 40

- DNA is in cytoplasm - No mRNA editing - Ribosomes read mRNA as it is being transcribed

Question 41

Who determined the 3-letter (triplet) codon system

Answer 41

Crick

Question 42

- Determined mRNA-amino acid match - Added fabricated mRNA to test tube of ribosomes, tRNA and amino acids - Created artificial UUUUU… mRNA

Answer 42

Nirenberg (1960) and Khorana (1968)

Question 43

UUU coded for __

Answer 43

Phenylalanine

Question 44

Strongest support for a common origin for all life

Answer 44

Code for ALL life

Question 45

- Several codons for each amino acid - 3rd base “wobble”

Answer 45

Code is redundant

Question 46

Start codon

Answer 46

- AUG - Methionine

Question 47

Stop codons

Answer 47

- UGA - UAA - UAG

Question 48

Why is wobble good?

Answer 48

Buffer for mutation

Question 49

Transfer RNA structure

Answer 49

“Clover leaf” structure

Question 50

- Enzyme which bonds amino acid to tRNA - Bond requires energy - ATP > AMP - Energy stored in tRNA-amino acid bond

Answer 50

Aminoacyl tRNA synthetase

Question 51

Facilitate coupling of tRNA anticodon to mRNA codon

Answer 51

Ribosomes

Question 52

2 subunits ribosomal RNA

Answer 52

- Large - Small

Question 53

Holds tRNA carrying next amino acid to be added to chain

Answer 53

A site (aminoacyl-tRNA site)

Question 54

Holds tRNA carrying growing polypeptide chain

Answer 54

P site (peptidyl-tRNA site)

Question 55

Empty tRNA leaves ribosome from ___ ___

Answer 55

E site (exit site)

Question 56

Brings together mRNA, ribosome subunits, initiator tRNA

Answer 56

Initiation

Question 57

Adding amino acids based on codon sequence

Answer 57

Elongation