Medical Cell Biology and Genetics (MCBG) Flashcards

1
Q

What is heterochromatin and does it show as light or dark in em?

A

DNA stored as solenoids.

Dark.

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

What is euchromatin and does it show up as light or dark in em?

A

DNA stored as beads on a string.

Light.

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

Are euchromatin or heterochromatin genes expressed?

A

Euchromatin

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

What is the limit of resolution?

A

The minimum distance at which two objects can be distinguished.

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

How do prokaryotic cells differ from eukaryotic cells?

A

Prokaryotes have no nucleus, they have a cell wall and no membrane bound organelles (all biochemical processes occur in the same compartment).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the parts of a phospholipid?

A

Hydrophilic head- choline, phosphate, glycerol

Hydrophobic tail- 2 fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does amphipathic man?

A

Both hydrophilic and hydrophobic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the glycocalyx?

A

Cell sugar coat on outside of plasma membrane

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

What is the fluid mosaic model?

A

Phospholipid bilayer

Proteins embedded in the bilayer

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

What are the functions of the plasmalemma?

A
Selective permeability
Transport of materials along cell surface
Endo/exocytosis 
Intercellular adhesion/recognition
Signal transduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Function of RER

A

Protein synthesis

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

Function of SER

A

Lipid synthesis and transport

Ovary/testis/adrenal gland- steroidogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where is the destination of the product of free ribosomes and ribosomes on the RER?

A

Free-cytoplasm

RER-for export

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

Which sides are the cis and trans faces of the Golgi body?

A

Cis-side closest to RER

Trans-opposite side

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

Functions of Golgi body?

A

Modify, sort , concentrate and package proteins into vesicles

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

What are the types of secretion?

A

Signal-mediated diversion to lysosomes
Constitutive secretion
Signal-mediated diversion to secretory vesicles for regulated secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the difference between primary and secondary lysosomes?

A

Secondary lysosomes have already fused with a bacterium and broken it down. Bacterial matter is left inside.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What makes lysosomes?

A

Golgi apparatus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What do lysosomes do?

A

Fuse with material requiring digestion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What do peroxisomes do?

A

Detoxify molecules in the liver/kidney including alcohol, phenols, formed acid and formaldehyde

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How often do mitochondria divide?

A

Every time the cell divides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How are actin microfilaments distributed in the cell?

A

Around the edge and in microvilli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How are intermediate filaments distributed in the cell?

A

Evenly around the cell (not microvilli)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How are microtubules distributed in the cell?

A

Branching out from nucleus (not microvilli)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How are microtubules arranged in a cilium/flagellum?

A

9+2 arrangement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What type of helix is DNA?

A

Right-handed alpha helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the major groove?

A

Large gap in side of helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How is DNA packaged?

A

DNA is wrapped around histones with linker DNA connecting each of these. 8 histones make up one nucleosome. These beads on a string are then packaged into solenoids.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What are genes?

A

They carry the code for proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the genome?

A

Entire DNA sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is a nucleoside?

A

Base and sugar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What is a nucleotide?

A

Base, sugar and phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the difference between ribose and 2-deoxyribose?

A

There is no O on the second carbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Why is DNA negatively charged?

A

The phosphate group is negatively charged

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Which bases are purines?

A

Adenine and guanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Which bases are pyramidines?

A

Cytosine, uracil, thymine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What type of polarity does DNA have?

A

5’ to3’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Why is DNA 5’ to 3’?

A

A phosphate is bonded to both the 3rd and 5th carbon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

How many hydrogen bonds form between G andC?

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How many bonds form between A and T?

A

2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is heterochrimatin and does it show as light or dark in em?

A

DNA stored as solenoids.

Dark.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What is euchromatin and does it show up as light or dark in em?

A

DNA stored as beads on a string.

Light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Are euchromatin or heterochromatin genes expressed?

A

Euchromatin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is the limit of resolution?

A

The minimum distance at which two objects can be distinguished.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

How do prokaryotic cells differ from eukaryotic cells?

A

Prokaryotes have no nucleus, they have a cell membrane and no membrane bound organelles (all biochemical processes occur in the same compartment).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are the parts of a phospholipid?

A

Hydrophilic head- choline, phosphate, glycerol

Hydrophobic tail- 2 fatty acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What does amphipathic man?

A

Both hydrophilic and hydrophobic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is the glycocalyx?

A

Cell sugar coat on outside of plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What is the fluid mosaic model?

A

Phospholipid bilayer

Proteins embedded in the bilayer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What are the functions of the plasmalemma?

A
Selective permeability
Transport of materials along cell surface
Endo/exocytosis 
Intercellular adhesion/recognition
Signal transduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Function of RER

A

Protein synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Function of SER

A

Lipid synthesis and transport

Ovary/testis/adrenal gland- steroidogenesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Where is the destination of the product of free ribosomes and ribosomes on the RER?

A

Free-cytoplasm

RER-for export

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Which sides are the cis and trans faces of the Golgi body?

A

Cis-side closest to RER

Trans-opposite side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Functions of Golgi body?

A

Modify, sort , concentrate and package proteins into vesicles

56
Q

What are the types of secretion?

A

Signal-mediated diversion to lysosomes
Constitutive secretion
Signal-mediated diversion to secretory vesicles for regulated secretion

57
Q

What is the difference between primary and secondary lysosomes?

A

Secondary lysosomes have already fused with a bacterium and broken it down. Bacterial matter is left inside.

58
Q

What makes lysosomes?

A

Golgi apparatus

59
Q

What do lysosomes do?

A

Fuse with material requiring digestion

60
Q

What do peroxisomes do?

A

Detoxify molecules in the liver/kidney including alcohol, phenols, formed acid and formaldehyde

61
Q

How often do mitochondria divide?

A

Every time the cell divides

62
Q

How are actin microfilaments distributed in the cell?

A

Around the edge and in microvilli

63
Q

How are intermediate filaments distributed in the cell?

A

Evenly around the cell (not microvilli)

64
Q

How are microtubules distributed in the cell?

A

Branching out from nucleus (not microvilli)

65
Q

How are microtubules arranged in a cilium/flagellum?

A

9+2 arrangement

66
Q

What type of helix is DNA?

A

Right-handed alpha helix

67
Q

What is the major groove?

A

Large gap in side of helix

68
Q

How is DNA packaged?

A

DNA is wrapped around histones with linker DNA connecting each of these. 8 histones make up one nucleosome. These beads on a string are then packaged into solenoids.

69
Q

What are genes?

A

They carry the code for proteins

70
Q

What is the genome?

A

Entire DNA sequence

71
Q

What is a nucleoside?

A

Base and sugar

72
Q

What is a nucleotide?

A

Base, sugar and phosphate

73
Q

What is the difference between ribose and 2-deoxyribose?

A

There is no O on the second carbon

74
Q

Why is DNA negatively charged?

A

The phosphate group is negatively charged

75
Q

Which bases are purines?

A

Adenine and guanine

76
Q

Which bases are pyramidines?

A

Cytosine, uracil, thymine

77
Q

What type of polarity does DNA have?

A

5’ to3’

78
Q

Why is DNA 5’ to 3’?

A

A phosphate is bonded to both the 3rd and 5th carbon

79
Q

How many hydrogen bonds form between G andC?

A

3

80
Q

How many bonds form between A and T?

A

2

81
Q

How is DNA replicated?

A

Initiation:
DNA polymerase binds to 3’ end of DNA after recognition of origin of replication. A kick-start by primate is required
Elongation:
Helicase unwinds double helix
Replication forks move
The DNA polymerase works in the 3’ to 5’ direction, making a new strand from 5’ to 3’. On the lagging strand this causes Okazaki fragments to form. DNA ligase joins these Okazaki fragments.
Termination:
Occurs when two replication forks meet and DNA ligase joins final fragments

82
Q

In which phase of the cell cycle does DNA replication occur?

A

S phase of interphase

83
Q

Which is the p arm on a chromosome?

A

The short arm

84
Q

What are telomeres?

A

Repeated sequences at the end of a chromosome

85
Q

Where can centromeres be positioned in a chromosome?

A

Metacentric (middle)
Submetacentric (between middle and end)
Arocentric (near end)
Telocentric (at end-not in humans)

86
Q

Explain mitosis

A

Prophase-nuclear membrane breaks down, spindle fibres appear, chromosomes condense
Prometaohase-microtubles connect to kinetochore spindle fibre, chromosomes condense
Metaphase-chromosomes line up at metaphase plate
Anaphase-centromeres divide and spindles pull sister chromatids apart
Telophase-spindles disappear, nuclear membrane reforms, chromosomes decondense
Cytokinesis-cytoplasm divides
2 identical cells

87
Q

Explain meiosis

A

Meiosis 1- same as mitosis 1 but no prometaphase and homologous pairs (tetrad) pulled apart
Meiosis 2-sister chromatids pulled apart
4 haploid cells

88
Q

What causes genetic diversity in meiosis?

A

Random assortment of chromosomes (metaphase)

Recombination/crossing over at a chiasma (prophase 1)

89
Q

What is nondisjunction?

A

When a centromere fails to split in anaphase

90
Q

How do you karyotype?

A

Chromosome number,sex complement,structural changes

91
Q

What is aneuploidy?

A

Abnormal number of chromosomes

92
Q

What does non-disjunction cause?

A

Aneuploidy

93
Q

What is mosaicism?

A

Presence of two or more cell lines in an individual, degree of mosaicism depends on when mistake occurs

94
Q

What are some functions of proteins?

A
Catalysts
Transporters
Structural support
Immune protection 
Ion channels
Receptors
95
Q

What determines the 3D structure of proteins?

A

Sequence of amino acids

96
Q

What are amino acids’ structure?

A

NH2, COOH, H, R groups around a central carbon atom

97
Q

What is an amino acid residue?

A

What remains of an amino acid after it has been joined by a peptide bond to form a protein.

98
Q

How can amino acids be classified?

A
Hydrophilic/phobic
Polar/non-polar
Acidic
Basic
Neutral
Aliphatic/aromatic
99
Q

What bonds are involved in the primary structure of proteins?

A

Covalent

100
Q

What bonds are involved in the secondary structure of proteins?

A

Hydrogen bonds

101
Q

What bonds are involved in the tertiary structure of proteins?

A

Disulphide, Ionic, hydrogen, van der waals, hydrophobic

102
Q

What bonds are involved in the quaternary structure of proteins?

A

Disulphide, ionic, hydrogen, hydrophobic, van dear waals

103
Q

Which amino acids are disulphide bonds formed between?

A

Cytosine residues

104
Q

What do electrostatic interactions occur between?

A

Charged groups

105
Q

What is hydrophobic effect?

A

Interaction between hydrophobic side chains. Hydrophobic molecules will come together so less of their surface is exposed to water.

106
Q

What is a normally folded protein in?

A

Native conformation

107
Q

How do proteins fold?

A

The folding process is ordered. Each step involves localised folding with stable conformations maintained.
Driven by need to find most stable conformation.

108
Q

What are amyloid fibres?

A

Misfolded, insoluble form of a normally soluble protein

109
Q

What is the genotype?

A

Genetic makeup of a person

110
Q

What is the phenotype?

A

The physical characteristics a person has

111
Q

What does hemizygous mean?

A

Only one allele of a gene on the X chromosome (males)

112
Q

What happens if a disease is autosomal recessive?

A

Heterozygotes are not affected
Males and females are equally affected
2 heterozygotes have 25% chance of having affected offspring
2 homozygous recessive people will have affected children
Disease can skip generations

113
Q

What happens if a disease is autosomal dominant?

A

Heterozygotes are affected (rare to be homozygous dominant)
Males and females are equally affected
Affected individuals have a 50% chance of having affected offspring
Affected individuals have at least one affected parent
Does not skip generations

114
Q

What happens if a disease is x linked recessive?

A

Hemizygous males and homozygous females affected
More common in males
Female carriers have a 50% chance of having affected sons
Affected males cannot give trait to sons
Affected males have at least a carrier mother
Affected females have an affected father and carrier mother
Daughters of affected males are at least heterozygous

115
Q

What happens if a disease is x linked dominant?

A

Hemizygous males and heterozygous females affected
Heterozygous females have 50% chance of having affected offspring
Affected males cannot give trait to sons but give it to all their daughters

116
Q

What are linked genes?

A

Genes on the same chromosome

117
Q

What is the genotype?

A

Genetic makeup of a person

118
Q

What is the phenotype?

A

The physical characteristics a person has

119
Q

What does hemizygous mean?

A

Only one allele of a gene on the X chromosome (males)

120
Q

What happens if a disease is autosomal recessive?

A

Heterozygotes are not affected
Males and females are equally affected
2 heterozygotes have 25% chance of having affected offspring
2 homozygous recessive people will have affected children
Disease can skip generations

121
Q

What happens if a disease is autosomal dominant?

A

Heterozygotes are affected (rare to be homozygous dominant)
Males and females are equally affected
Affected individuals have a 50% chance of having affected offspring
Affected individuals have at least one affected parent
Does not skip generations

122
Q

What happens if a disease is x linked recessive?

A

Hemizygous males and homozygous females affected
More common in males
Female carriers have a 50% chance of having affected sons
Affected males cannot give trait to sons
Affected males have at least a carrier mother
Affected females have an affected father and carrier mother
Daughters of affected males are at least heterozygous

123
Q

What happens if a disease is x linked dominant?

A

Hemizygous males and heterozygous females affected
Heterozygous females have 50% chance of having affected offspring
Affected males cannot give trait to sons but give it to all their daughters

124
Q

What are linked genes?

A

Genes on the same chromosome

125
Q

What do linked genes not show?

A

Independent assortment at meiosis

126
Q

What happens to recombination frequency as the genes are further apart on a chromosome?

A

It increases

127
Q

What are tightly linked genes?

A

Genes close together on the same chromosomes

128
Q

What happens in transcription?

A

Promoter region is recognised
Transcription initiation factors recruit RNA polymerase
RNA polymerase makes RNA in 5’ to 3’ direction

129
Q

What are the subunits in prokaryotic ribosomes?

A

50s and 30s

Overall 70s

130
Q

What are the subunits in eukaryotic ribosomes?

A

60s and 40s

Overall 80s

131
Q

How are stem loops created?

A

Hydrogen bonds are formed between anti-parallel, complementary sequences

132
Q

Where is the amino acid attached to tRNA?

A

3’ end

133
Q

What is the wobble position?

A

The 5’ base of an anticodon/3’ base of a codon is the wobble position allowing a tRNA species to recognise more than one codon

134
Q

How are amino acids joined to tRNA?

A

An amino acid binds to an enzyme using ATP. Then the specific tRNA molecule binds to the enzyme using ATP and the amino acid of joins to the tRNA molecule and is released.

135
Q

What happens in translation?

A

A methionine 40s subunit recognises the cap and start codon and binds to it using ATP. The 60s subunit then joins the 40s subunit.
A complementary tRNA molecule binds to the codon using GTP. A peptide is formed between adjacent amino acids and the uncharged tRNA leaves the site and the ribosome moves along the RNA using GTP. This continues until the stop codon is reached and the tRNA leaves the reading site.

136
Q

What is the p site of a ribosome?

A

The first reading site

137
Q

What is the a site of a ribosome?

A

The second reading site