Chapter 3 (I)

Question 1

what is the life time of a single cell called?

Answer 1

cell cycle

Question 2

the cell spends most of its time in the ______ part of the cell cycle.

Answer 2

interphase

Question 3

what are the 3 stages in interphase?

Answer 3

G1, S, and G2

Question 4

what stage of interphase is involved in growth, is metabolically active, synthesizes proteins rapidly, and begins centriole replication?

Answer 4

G1

Question 5

what stage of interphase is involved in growth and DNA synthesis, and forms new histones to assemble into chromatin?

Answer 5

S

Question 6

what stage of interphase is involved in growth and synthesis of enzymes/proteins, moves them to their proper sites, completes centriole replication, and is ready to divide?

Answer 6

G2

Question 7

DNA synthesis begins simultaneously on several ______ and at several _______ of replication, which _______ speed of the reaction.

Answer 7

begins simultaneously on several chromatin threads
and at several origins of replication
which increases speed of reaction.

Question 8

what are the 4 steps of DNA replication?

Answer 8

1. uncoiling (enzyme unwinds DNA, form replication bubble)
2. separation (DNA strands separate as H bonds between base pairs are broken)
3. assembly (old strands act as template & DNA polymerase add nucleotides to template strand)
4. restoration (ligase enzymes splice short segments of DNA together to restore double helix structure)

Question 9

what happens if DNA is damaged?

Answer 9

stops at the the G2/M checkpoint until DNA repair mechanism fixes problem

Question 10

what do histones do during replication?

Answer 10

associate with DNA to form chromatin strands

Question 11

cell division

Answer 11

body growth and tissue repair

Question 12

mitosis divides the ______ while cytokinesis divides the ______.

Answer 12

mitosis divides nucleus

cytokinesis divides cytoplasm

Question 13

4 phases of mitosis?

Answer 13

prophase, metaphase, anaphase, telophase

Question 14

what draws plasma inward to form cleavage furrow?

Answer 14

contractile ring

Question 15

what is the contractile ring made of?

Answer 15

actin filaments

Question 16

ratio of cell surface area to cell volume,
chemical signals (growth factors/hormones),
availability of space,
G1 and G2/M checkpoints,
and repressor genes control what?

Answer 16

controls cell division

Question 17

what is the purpose of cyclins and CDKs?

Answer 17

cyclins are regulatory proteins made in G1 to power synthesis and division

CDKs bind to cyclins to be activated- tag enzymes with protein to start enzyme cascade to prepare for division

Question 18

what is the function of G1 checkpoint and G2/M checkpoint?

Answer 18

G1- tell to go to S phase

G2/M- tell to go to M phase

Question 19

what are p53 and retinoblastoma (Rb) genes?

Answer 19

repressor genes that suppress tumors/prevent cancer

Question 20

what is a segment of DNA molecule that carries instructions for creating one polypeptide chain?

Answer 20

gene

Question 21

what is the ratio of DNA bases in a gene to amino acids in a polypeptide?

Answer 21

3:1

Question 22

what region codes for amino acids and what region is non-coding?

Answer 22

coding- exons

noncoding- introns

Question 23

what is the purpose of introns?

Answer 23

omit/include certain exons
allow exons to be swapped between genes
allow novel combinations

Question 24

what is the role of RNA

Answer 24

DNA decoding mechanism and messenger

Question 25

what RNA does this describe: a single strand with introns spliced out carry coded info to cytoplasm where protein synthesis occurs carry instructions for building polypeptides from gene in DNA to ribosomes in cytoplasm

Answer 25

mRNA

Question 26

what RNA does this describe: forms ribosomes (2 subunits) sites for protein synthesis makes proteins based on mRNA message

Answer 26

rRNA

Question 27

what RNA does this describe: ferry amino acids to ribosomes decode mRNA's message bind amino acids and pair with bases of codons

Answer 27

tRNA

Question 28

transcription

Answer 28

DNA's info encoded in mRNA (DNA to mRNA)

Question 29

translation

Answer 29

info carried by mRNA decoded used to assemble polypeptides (mRNA to protein)

Question 30

transcription cannot begin until ______ stimulate histones to loosen.

Answer 30

transcription factors

Question 31

where does the transcription factor bind?

Answer 31

promoter

Question 32

what is the region of DNA that serves as the start point and specifies template?

Answer 32

promoter

Question 33

what oversees synthesis of mRNA and initiates transcription?

Answer 33

RNA polymerase

Question 34

what are the 3 phases of transcription?

Answer 34

1. initiation: RNA polymerase bind to promoter, pull apart DNA strands, begin mRNA synthesis 2. elongation: RNA polymerase moves along template to join RNA nucleotides complementary to DNA 3. termination: reach termination signal, mRNA transcript released

Question 35

how is mRNA processed?

Answer 35

remove introns by spliceosomes

Question 36

why are some amino acids represented by more than 1 codon?

Answer 36

protect against errors

Question 37

what RNA bonds to amino acids and mRNA codon? and what is the attachment process controlled by?

Answer 37

tRNA binds to amino acids and mRNA codon | aminoacyl-tRNA synthetase enzyme activated by ATP controls the attachment process

Question 38

once an amino acid is loaded, tRNA diffuse to _______ where amino acid is positioned.

Answer 38

ribosome

Question 39

what site receives incoming aminoacyl-tRNA?

Answer 39

A site

Question 40

what site involved tRNA holding growing polypeptide chain?

Answer 40

P site

Question 41

what site is made for outgoing RNA?

Answer 41

E site

Question 42

where does translation occur and what does it require?

Answer 42

occur in cytosol | requires ATP, protein factors, and enzyme

Question 43

what are the 3 steps in translation?

Answer 43

1. initiation (4 components combine at P site) 2. elongation (amino acids add 1 at a time to growing peptide chain) 3. termination (stop codon -UGA, UAA, UAG- arrives at A site and elongation stops)

Question 44

what directs the mRNA-ribosome complex to the rough ER?

Answer 44

signal recognition particle

Question 45

what is the role of rough ER in protein synthesis?

Answer 45

enclose protein in vesicle for transport to golgi apparatus