Protein Synthesis, Mitosis & Meiosis Flashcards Preview

Anatomy & Physiology 200 > Protein Synthesis, Mitosis & Meiosis > Flashcards

Flashcards in Protein Synthesis, Mitosis & Meiosis Deck (25):
0

What are the two stages of protein synthesis?

Transcription
Translation

1

What are the matching base pairs for DNA?

Thyamine -- adenine
Guanine -- cytosine

2

What are the matching base pairs for RNA?

Adenine -- uracil
Guanine -- cytosine

3

Where does transcription occur?

Nucleus

4

DNA helicase

Unzips DNA so it can be transcribed

5

What are the steps of transcription?

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.

6

RNA polymerase

Transcribes DNA. Reads segment and creates complementary RNA.

7

snRNPs

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

8

Introns

"Useless" segments of RNA

9

Exons

Useful segments of RNA

10

Alternative splicing

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

11

Steps of Translation

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.

12

Methionine

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

13

Polyribosome

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

14

Homologous vs sister chromotids

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.

15

Phases of interphase

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.

16

Prophase (mitosis)

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

Nuclear envelope dissolves.

17

Kinetochore

Helps stabilize chromosome centromere.

18

Metaphase (mitosis)

Chromosomes line up along metaphasic plate.

19

Anaphase (mitosis)

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

Cleavage furrow develops.

20

Telophase (mitosis)

Chromatids arrive at poles. Cleavage furrow deepens.

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

21

Prophase I

Meiosis

Sister chromatids of homologous chromosomes create tetrads through synapses.

Genetic recombination/crossing over occurs.

22

Metaphase I

Homologous chromosomes line up at metaphasic plate

23

Anaphase I

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

24

Telophase I

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