sem 2 final: part 2

Question 1

What happens during G1 phase of INTERPHASE?

Answer 1

Gene expression and cellular respiration (producing ATP)

Question 2

What happens during S phase of INTERPHASE?

Answer 2

DNA replicates creating two identical DNA strands

Question 3

What happens during G2 phase of INTERPHASE?

Answer 3

Cell prepares to divide by replenishing energy, synthesizing proteins, and growing in size

Question 4

What happens during the phases of MITOSIS (prophase, metaphase, anaphase, telophase)?

Answer 4

PROPHASE: Chromosomes condense forming two chromatids. Nuclear membrane disintegrates causing spindle to form. METAPHASE: Spindle organizes chromosomes on equator of the cell. Some spindle fibers attach to the centromeres and some span the cell. M-checkpoint occurs. ANAPHASE: Some spindle shorten which pull the chromatids apart. Some spindle lengthen which cause cell to elongate. TELOPHASE: Two new nuclei form.

Question 5

How do plant cells divide?

Answer 5

Plant cells construct a new cell plate. The materials needed to do so are delivered by vesicles from Golgi.

Question 6

How do animal cells divide?

Answer 6

A ring assembles in the middle of cell creating a cleavage furrow that moves inward (energy using process) to separate the two cells.

Question 7

Cyclins

Answer 7

Cyclins control cell cycle progression by determining whether it will be fast or slow. Mutations in cyclin genes can lead to cancer. Cells cannot progress in cell cycle unless specific cyclins (D, E, A, B) reach a certain concentration.

Question 8

What’s chromatin?

Answer 8

Substance in cell’s nucleus that’s composed of DNA and proteins

Question 9

Helicase

Answer 9

Unzips DOUBLE HELIX by breaking HYDROGEN BONDS at ORIGIN OF REPLICATION forming REPLICATION BUBBLES. Within replication bubbles are replication forks that elongate DNA.

Question 10

Gyrase

Answer 10

Unwinds the supercoil of DNA in a way that keeps DNA from breaking, relieving strain.

Question 11

Primase

Answer 11

Adds RNA nucleotides (primer) to complementary base pairs.

Question 12

DNA Polymerase III

Answer 12

Adds DNA nucleoside triphosphate to RNA primer sequence in 5’ to 3’ direction.

Question 13

DNA Polymerase I

Answer 13

RNA primers are digested and replaced with DNA nucleotides.

Question 14

Ligase

Answer 14

Joins okazaki fragments on lagging strand to form a single DNA strand.

Question 15

DNA Replication Order

Answer 15

Gyrase, Helicase, Single Stranded Binding Proteins, Primase, DNA Polymerase III, DNA Polymerase I, Ligase

Question 16

What nitrogenous bases do PURINES have and how many rings do they have?

Answer 16

A & G, 2 rings

Question 17

What nitrogenous bases do PYRIMIDINES have and how many rings do they have?

Answer 17

T U & C, 1 ring

Question 18

Transcription

Answer 18

INITIATION begins when double helix unwinds and RNA polymerase binds to DNA. ELONGATION is when nucleotides are added to mRNA in 3’ to 5’ region. TERMINATION is when mRNA synthesis is complete which begins disassembly.

Question 19

Role of nucleosomes

Answer 19

Represses all transcription processes

Question 20

Role of promoter

Answer 20

Controls whether RNA polymerase can access the gene

Question 21

Role of silencer & enhancer

Answer 21

Silencer & Enhancers are non-coding DNA base sequence that regulate gene expression

Question 22

Role of repressor

Answer 22

When repressor is added to operator, promoter stops binding with RNA polymerase

Question 23

Free ribosomes

Answer 23

Synthesizes proteins in mitochondria, chloroplasts, cytoplasm, and nucleus

Question 24

Bound ribosomes

Answer 24

Synthesizes proteins in ER, Golgi apparatus, lysosomes, plasma membrane, and ones that are to be exported out of cell

Question 25

Translation

Answer 25

INITIATION begins when mRNA binds to small & large ribosomal subunits. ELONGATION is when aminoacyl-tRNA binds to A site. TERMINATION is when release factor binds to A site and disassembly begins.

Question 26

Single Stranded Binding Proteins

Answer 26

Bind to parental DNA right after helicase to prevent 2 single strands from reforming double helix