Protein Synthesis, Mitosis & Meiosis

Question 0

What are the matching base pairs for DNA?

Answer 0

Thyamine – adenine

Guanine – cytosine

Question 1

What are the two stages of protein synthesis?

Answer 1

Transcription

Translation

Question 2

What are the matching base pairs for RNA?

Answer 2

Adenine – uracil

Guanine – cytosine

Question 3

Where does transcription occur?

Answer 3

Nucleus

Question 4

DNA helicase

Answer 4

Unzips DNA so it can be transcribed

Question 5

What are the steps of transcription?

Answer 5

Starting at promoter sequence, RNA polymerase reads one strand of DNA.

From base triplets on DNA, creates complementary codons. Continues until reaches terminator region.

Pre-mRNA gets edited by snRNPs and then travels to cytoplasm for translation.

Question 6

RNA polymerase

Answer 6

Transcribes DNA. Reads segment and creates complementary RNA.

Question 7

snRNPs

Answer 7

Snurps
Small nuclear ribonuclear proteins
Responsible for splicing pre-mRNA (editing out the introns).

Question 8

Introns

Answer 8

“Useless” segments of RNA

Question 9

Exons

Answer 9

Useful segments of RNA

Question 10

Alternative splicing

Answer 10

A segment of RNA can be spliced in different ways, so identical RNA sequences can end up producing a multitude of proteins.

Question 11

Steps of Translation

Answer 11

mRNA attaches to rRNA.

Initiator tRNA (UAC) attaches to AUG on mRNA. Ribosomal subunits come together to start synthesis. Initiator tRNA fits into P site.

Another tRNA matches up with next codon in A site. The amino acid it carries will create a peptide bond with the methionine carried by the initiator tRNA.

Initiator tRNA, it’s job done, releases the methionine, departs from P site. Second tRNA moves from A site to P site. Next codon is matched to tRNA in A site, new AA attached , yadda yadda yadda.

Continues until stop codon reached.

Question 12

Methionine

Answer 12

The amino acid produced by initiator tRNA. Codon: AUG. Anticodon: UAC

Question 13

Polyribosome

Answer 13

Produced when multiple ribosomes attach to the same mRNA to produce multiple copies of the same amino acid chain.

Question 14

Homologous vs sister chromotids

Answer 14

Homologous: same chromosome (ie chromosome 23 or 16), but not identical (in humans, one would come
from each parent).

Sister: identical. Created when chromatid cloned during S phase of interphase.

Question 15

Phases of interphase

Answer 15

1. G1. Organelles (not chromosomes) replicated.
2. S. DNA replication. Now cell has 96 chromatids.
3. G2. Cell grows. Centrosome replication complete. DNA checked for errors.

Question 16

Prophase (mitosis)

Answer 16

Chromatin condense into characteristic X shape, held together by centromeres.

Nuclear envelope dissolves.

Question 17

Kinetochore

Answer 17

Helps stabilize chromosome centromere.

Question 18

Metaphase (mitosis)

Answer 18

Chromosomes line up along metaphasic plate.

Question 19

Anaphase (mitosis)

Answer 19

Mitotic spindles pull chromosomes toward each pole. Centromeres split apart. One of each sister pair will move to each pole.

Cleavage furrow develops.

Question 20

Telophase (mitosis)

Answer 20

Chromatids arrive at poles. Cleavage furrow deepens.

Nuclear envelope reforms, plasma membrane regenerated, and two identical daughter cells exist.

Question 21

Prophase I

Answer 21

Meiosis

Sister chromatids of homologous chromosomes create tetrads through synapses.

Genetic recombination/crossing over occurs.

Question 22

Metaphase I

Answer 22

Homologous chromosomes line up at metaphasic plate

Question 23

Anaphase I

Answer 23

Homologous chromosomes separate to either pole (different from mitosis, in which sister chromatids are separated).

Question 24

Telophase I

Answer 24

Nuclear envelope reforms, cell membrane repairs, and two haploid daughter cells are left, each with a pair of slightly recombined sister chromatids.