Test 3 - Cellular And Molecular Genetics Flashcards Preview

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Flashcards in Test 3 - Cellular And Molecular Genetics Deck (16):
1

What is a gene?

Region of DNA that controls a hereditary characteristic, usually corresponding to a single protein or RNA.

2

What is the most common form of DNA?

Nucleosomes
-DNA wrapped around histones
—DNA in nucleosome form is called chromatin

*In general, DNA is organized into chromosomes

3

How many chromosomes do humans have?

46

44 autosomes

2 sex chromosomes

4

What is a LINE?

What is a SINE?

LINE - Long interspersed nuclear elements

SINE - Short interspersed nuclear elements

5

What are the different stages of the cell cycle?

3 main:

Interphase
-G0 - Majority of cell life and function
-G1 - Cell organelles duplicated
-S - Chromosomes duplicated
-G2 - Cell double checks chromosomes

Mitosis
-Prophase - Chromosomes condense
-Prometaphase - Kinetochore microtubules formed and breakdown of nuclear envelope
-Metaphase - Line up in middle
-Anaphase - Pull apart
-Telophase - Start separation process, chromosomes decondense

Cytokinesis - Cell splits via a contractile ring of actin and myosin filaments that pinches the cell

6

DNA replication is __________.

What part of the cell cycle does that occur in?

Semiconservative

S phase

7

DNA must be synthesized in what direction?

And at what?

5’ to 3’

Replication forks

8

What does DNA polymerase do?

Polymerizes new DNA strands

9

What does topoisomerase do?

Places nicks in the DNA to relax coils

10

What does DNA primase do?

Creates RNA primers on the lagging strand

11

What does DNA helicase do?

Unwinds the DNA
-Into a leading strand and lagging strand

12

What primary DNA polymerase creates strands?

Epsilon

13

4 most common types of DNA damage?

Mismatch

Deamination
-Amine removed

Depurination
-Purine removed

Double strand break

14

What increases genetic diversity and by what processes?

Chromosome assortment

Independent assortment

Recombination
-Bivalent chromosomes
—Crossing over

15

Recombination is directed by what?

Recombinases

-DS - Recombinase DNA Merging

-SS - Hollday Junctions

16

What are the 3 classes of transposable elements?

How are transposons inserted? (3 ways)

DNA-only transposons
-Short inverted repeats at ends
-encodes transposase
-NO RNA INTERMEDIATES

Retroviral-like retrotransposons
-Directly repeated long terminal repeats at ends
-encodes reverse transcriptase and resembles retro virus
-RNA INTERMEDIATE REQ’D BY PROMOTER IN LTR (long terminal repeats)

Nonretroviral retrotransposons
-Poly A at 3’ end of RNA transcript, 5’ is often truncated
-RNA INTERMEDIATE REQ’D BY NEIGHBORING PROMOTER

Cut and paste
Viral insertion
Replication