Molecular genetics Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Chromatin threads

A
  • made up of histone proteins coiled arnd deoxyribonucleic acid (DNA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How is DNA organised inside cell nucleus (each DNA molecule)

A
  • consists of 2 anti-parallel strands, twisted arnd each other, double helix
  • wrapped arnd histone proteins
  • during cell div, chromatin threads coil tightly to form chromosome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define DNA

A
  • molecule that carries genetic info
  • made up of nucleotides (basic unit of DNA)
  • each DNA nucleotide made up of
    1. a deoxyribose (sugar) molecule
    2. phosphate group
    3. a nitrogen-containing base
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Nitrogen-containing base

A
  • 4 types
  • adenine (A)
  • cytosine (C)
  • guanine (G)
  • thymine (T)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Polynucleotides

A
  • formed when nucleotides join tgt by condensation
  • DNA molecule made of 2 anti-parallel polynucleotide strands (double-helix)
  • bases of both strand form tgt according to rule of base pairing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Rule of base pairing

A
  • Adenine and thysine (A&T)
  • Cytosine and guanine (C &G)
  • complementary bases
  • 1:1 ratio for A:T and G:C
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define gene

A
  • segment of DNA
  • specific sequence of nucleotides
  • controls synthesis of specific polypeptide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Codon

A
  • triplet code, 3 nucleotides forms an amino acid

genetic code states which amino acid each triplet code is for

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What happens when nucleotide sequence is altered?

A
  • known as gene mutation

- may or may not lead to change in protein product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Examples of gene mutation

A
  • refers to change in genetic material of a gene
  • e.g albinism, gene that cause absence/defect in melanin (enzyme that produces pigment)
  • e.g. sickle-cell anaemia, mutation in gene that causes protein product to differ from normal protein by 1 amino acid, RBC become sickle shaped
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are proteins made?

A
  • transcription

- translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Transcription (brief overview)

A
  • DNA separate out, 1 template DNA (Strand), 1 non-template DNA
  • occurs when DNA template transcribed into mRNA
  • occurs in nucleus of cell
  • DNA triplet code converted into mRNA codons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Translation (brief overview)

A
  • mRNA molecule translated into polypeptides

- occurs in cytoplasm of cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

DNA vs RNA (sugar unit)

A
  • DNA: deoxyribose

- RNA: ribose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

DNA vs RNA (nitrogenous bases)

A
  • DNA: Adensine (A), Thymine (T), Guanine (G), Cytosine (C)

- RNA: Uracil (U) instead of Thymine (T), rest same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

DNA vs RNA (ratio of nitrogenous bases)

A
  • DNA: A:T=1:1, G:C=1:1 (becos double helix, each base has a partner)
  • RNA: no fixed ratio (single-stranded, each base no partner)
17
Q

DNA vs RNA (size and solubility)

A
  • DNA: large, insoluble molecule (cannot leave nucleus)

- RNA: small, soluble molecule (can leave nucleus)

18
Q

DNA vs RNA (temporary vs permanent)

A
  • DNA: permanent molecule in nucleus

- RNA: temporary molecule, made when needed

19
Q

Translation (biological molecules involved)

A
  1. Amino acids: 20 types
  2. Transfer RNA molecules: tRNA, each has aa attached, aa attached depends on tRNA’s anticodon
  3. Ribosomes: help make polypeptides from mRNA
  4. mRNA molecules
20
Q

What happens during transcription? (4)

A
  1. Gene unzips
  2. DNA template formed in nucleus
  3. mRNA formed, complementary copy which contains uracil instead of thymine
  4. mRNA exits out of nucleus and enters cytoplasm
21
Q

What happens during translation? (6)

A
  1. mRNA attaches to ribosome
  2. tRNA with anticodon complementary to mRNA attaches to ribosome as ribosome moves along mRNA strand
  3. amino acids attached to tRNA forms peptide bonds with each other
  4. tRNA gets released, a new one fits into ribosome
  5. amino acids continually attached until ribosome reaches stop codon on mRNA, ribosome leaves mRNA
  6. complete polypeptide produced (chain of aa)