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Flashcards in Genetics Deck (65)
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1

DNA strand is read in which direction?

From 5' -> 3' end

2

DNA features (4)

Double stranded
Sugar/phosphate backbone
Sugar backbone is 2-deoxyribose
Pairs up in an antiparallel fashion

3

DNA base pairing

A binds with T (double hydrogen bond)
C binds with G (triple hydrogen bond)

4

Which type of bonds are formed between bases in DNA?

Hydrogen bonds

5

Mitosis

Production of 2 daughter cells
- identical to each other
- identical to the original parent cell

6

Mitosis phases (6)

1. S phase - duplicate genetic material
2. Metaphase - chromosomes align at equator
3. Anaphase - centromeres divide and chromatids move towards corresponding poles
4. Telophase - nucelar envelope appears which separates duplicated material into 2 identical daughter cells
5. Cytokinesis - cytoplasm divides, 2 identical daughter cells produced
6. Interphase - cell rests and produces new proteins

7

Meiosis

One diploid parent cell produces 4 haploid daughter cells
Genetic makeup is re-shuffled by crossing over

8

Meiosis phases (9)

1. Genetic material duplicated
2. Prophase 1 - crossing over occurs
3. Metaphase 1 - homologous chromosomes line up at equator
4. Anaphase 1 - homologous pairs separate
5. Telophase 1 - 2 daughter cells formed, each with only 1 chromosome
6. Prophase 2 - DNA does not replicate
7. Metaphase 2 - Chromosomes line up at equator
8. Anaphase 2 - chromosomes separate to each pole
9. Telophase 2 - cell division complete producing 4 haploid daughter cells

9

Cell cycle - G1

Growth phase
- cells increase in size
- cells produce RNA
- protein synthesis
- checkpoint at end of G1

10

Cell cycle - S phase

DNA replication

11

Cell cycle - G2

Growth phase 2
- cells further increase in size
- new proteins produced
- checkpoint at end of G2

12

Cell cycle - M phase

Mitosis occurs

13

DNA replication - what is needed to initiate DNA replication?

RNA primer (synthesised by primase)

14

DNA replication - leading strand

Always has a free 3' end for next nucleotide to join

15

DNA replication - lagging strand

Replicated in short segments (okazaki fragments)

16

DNA replication - what joins the lagging strand fragments together?

Ligase

17

DNA replication - what catalyses the reaction?

DNA polymerase

18

RNA features (3)

Single stranded
Ribose backbone
Uracil is used instead of thymine

19

Protein synthesis

DNA is transcribed to pre-mRNA
pre-mRNA is spliced to mRNA
mRNA is translated to a protein

20

DNA replication - What is used to unwind the DNA double helix?

Helicase

21

Exons

Coding regions

22

Introns

Non-coding regions

23

Splicing

Removes all introns and joins the eons together to form mRNA

24

DNA replication - where does transcription occur?

Nucleus

25

DNA replication - where does translation occur?

Ribosome

26

Polymorphism

Any variation in the human genome that does NOT cause disease in it's own right

27

Mutation

A genetic variation that can cause:
- a genetic disorder (disease)
- any change in the genome

28

Balanced chromosomal rearrangement

All chromosomal material is present
Chromosomal material is just switched around and not in the same order

29

Unbalanced chromosomal rearrangement

Extra/missing chromosomal material
eg: miscarriage, trisomy 14

30

Aneuploidy

A whole extra or missing chromosome
X chromosome aneuploidy is better tolerated (due to X-inactivation)