Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Higher Human Biology > Human Cells > Flashcards

Human Cells Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is a somatic cell?

A

Any body cell other than those involved in reproduction

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

How do somatic cells divide?

A

Mitosis

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

What are germline cells?

A

Gametes and the stem cells that divide to form gametes

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

How do germline cells divide?

A

By mitosis and meiosis

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

Does mitosis maintain the diploid chromosome complement?

A

Yes

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

How many homologous pairs are made in mitosis?

A

23

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

What does meiosis produce?

A

Haploid gametes

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

What are the two divisions that happen during meiosis?

A

1 - separating homologous chromosomes

2 - separating chromatids producing 23 single chromosomes in each haploid cell

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

How many daughter cells does mitosis produce?

A

2

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

How many daughter cells does meiosis produce?

A

4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is cellular differentiation?

A

The process by which a cell develops more specialised functions by selective gene expression

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

How does cellular differentiation work?

A

Only a fraction of the genes remain switched on so only those are expressed producing the characteristics specific proteins

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

What are stem cells?

A

Undifferentiated somatic cells

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

What do stem cells divide to do?

A

Make copies of themselves

Differentiate into specialised cells

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

Where are embryonic stem cells found?

A

A very early embryo

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

What are the genes like in an embryonic stem cell?

A

All of the genes have the potential to be switched on so they can differentiate into almost any cell type

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

What are embryonic stem cells known as?

A

Pluripotent

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

Where are tissue stem cells found?

A

In tissue and bone marrow

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

What are the genes like in tissue stem cells?

A

Many of the genes are already switched off so they can only differentiate into a limited number of cells (closely related to the tissue they are found in)

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

What can bone marrow differentiate into?

A

Different blood cells

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

What are tissue stem cells known as?

A

Multipotent

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

What are tissue stem cells involved in?

A

The growth, repair and renewal of cells found in that tissue

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

What do germline cells produce when they divide by meiosis?

A

Gametes

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

What do germline cells produce when they divide by mitosis?

A

Copies of themselves

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

What are the 2 therapeutic uses of stem cells?

A

Regeneration of damaged tissue

Corneal repairs

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

When can stem cells renew?

A

Under the right conditions in the lab

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

What are the 3 research uses of stem cells?

A

Model cells to study how diseases develop
For drug testing
They provide information on how cell processes such as cell growth, differentiation and gene regulation work

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

What are the ethical issues of stem cells?

A

They offer effective treatments for disease and injury, however it involves the destruction of embryos

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

Why do cancer cells divide excessively?

A

They don’t respond to regulatory signals - this results in a mass of abnormal/cancer cells known as a tumour

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

What happens if cells within the rumour fail to attach to each other?

A

They can spread throughout the body and form a secondary tumour

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

What does DNA stand for?

A

Deoxyribose nucleic acid

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

What are the two strands of repeating units in DNA called?

A

Nucleotides

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

What are nucleotides composed of?

A

Deoxyribose sugar
Phosphate
A base

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

What does a chemical bond form between?

A

The phosphate group of one nucleotide and the deoxyribose of another forming a sugar - phosphate backbone

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

What type of bonds join the bases on each strand if nucleotides to form base pairs?

A

Weak hydrogen bonds

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

What does the base sequence form?

A

The organisms genetic code

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

What structure does DNA have and what does this mean?

A

Anti-parallel
This means the 2 strands run in opposite directions with one end bearing the deoxyribose 3’ end and the other the phosphate 5’ end

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

What is the shape of DNA known as?

A

A double helix

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

When does DNA replication occur?

A

Before cell division

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

What does DNA replication begin with?

A

DNA unwinding

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

What is DNA replicated by?

A

A DNA polymerase

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

What 5 things are required for DNA replication?

A 
DNA template
Primers
Nucleotides
Enzymes
ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are primers?

A

Short strand of nucleotides which binds to 3’ end

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

What enzymes are used in DNA replication?

A

DNA polymerase and sometimes ligase

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

What is the process of DNA replication?

A

DNA unwinds

Hydrogen bonds break between
bases to form 2 template strands

Primer bonds to 3’ end to start replication

DNA polymerase adds new complementary nucleotides to the template strands from the primer onwards

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

What direction does replication occur?

A

3’ to 5’

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

What happens to the leading strand during DNA replication?

A

It is replicated continuously

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

What happens to the lagging strand during DNA replication?

A

New nucleotides can only be added to the 3’ end so it is replicated in fragments with many primers

Fragments are joined together by ligase

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

What happens in PCR?

A

DNA is amplified using complementary primers which are complementary to a specific target sequence at two ends of the region of DNA

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

How is the target region amplified during PCR?

A

By repeated cycles of cooling and heating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What happens when DNA is heated to 92-98°C in PCR?

A

Hydrogen bonds break and strands separate

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

What happens when mixture is cooled to 50-65°C in PCR?

A

Allows primers to bind to target sequences

53
Q

What happens when mixture is heated between 70-80°C in PCR?

A

Heat tolerant polymerase replicates region of DNA

54
Q

What is PCR used for?

A

Forensics to help solve crimes

Settle paternity suits

Diagnose genetic disorders

55
Q

What does gene expression involve?

A

Transcription and translation of DNA expressing only a fraction of the genes in a cell

56
Q

Describe RNA

A

Single stranded

Has uracil instead of thymine

Has ribose sugar instead of deoxyribose sugar

57
Q

What are the 3 types of RNA?

A

mRNA

tRNA

rRNA

58
Q

What is mRNA (messenger RNA) and what does it do?

A

mRNA is made of a series of base triplets known as codons

It carries a copy of the DNA code from the nucleus to ribosome

59
Q

What does a codon do?

A

Codes for a specific amino acid

60
Q

What is tRNA (transfer RNA) and what does it do?

A

Carries a specific amino acid to the ribosome

Folds due to complementary base pairing

Has an exposed triplet of bases known as an anticodon at one end

Has an attachment site for a specific amino acid at the other end

61
Q

What is rRNA (ribosomal RNA) and what does it do?

A

Forms the ribosome with proteins

62
Q

What is transcription?

A

The synthesis of mRNA from a section of DNA

63
Q

What happens in transcription?

A

RNA polymerase moves along the DNA strand unwinding and breaking the hydrogen bonds between the bases, adding new RNA nucleotides following RNA base pairing rules

RNA polymerase can only add new nucleotides to the 3’ end of the new mRNA strand

The resultant mRNA breaks off and is the primary transcript

64
Q

What happens during RNA splicing?

A

Regions of the transcript (in transcription) are known as introns and exons

Introns are cut out and exons joined together

Now known as the mature transcript

65
Q

What is translation?

A

The synthesis of a polypeptide from mRNA at the ribosome.

66
Q

What happens during translation?

A

Ribosome attaches to mRNA

Ribosome reads start codon to start translation

As ribosome reads each codon, complementary tRNA with anticodon and amino acid attached binds to codon

When the next codon is read and anticodon attaches, peptide bond forms between the two amino acids

tRNA molecule detaches from amino acid and leaves to pick up another

67
Q

What is the difference between introns and exons?

A

Introns are non-coding

Exons are coding

68
Q

What is alternative RNA splicing?

A

Different segments of mRNA may be treated as exons and introns

The same primary transcript can produce several mature transcripts

69
Q

What is a polypeptide?

A

Amino acids linked by peptide bonds

70
Q

What happens to polypeptides?

A

They fold to form a 3D shape held together by hydrogen bonds and interactions between individual amino acids

71
Q

What does the protein shape determine?

A

Their function

72
Q

What is the phenotype of a gene determined by?

A

The protein produced as a result of gene expression which can be influenced by environmental factors

73
Q

What is a mutation?

A

Change in the DNA that can result in no protein or an altered protein being synthesised

74
Q

What are the 3 types of single gene mutations?

A

Substitution
Insertion
Deletion

75
Q

What does a substitution mutation result in?

A

Missense mutations
Nonsense mutations
Splice-site mutations

76
Q

What is a missense mutation?

A

One amino acid being changed for another

Results in either a non-functional protein or very little effect on the protein

77
Q

What is a nonsense mutation?

A

A premature stop codon being produced

Resulting in a shortened protein

78
Q

What is a splice-site mutation?

A

Some introns being retained and/or some exons not being included in the mature transcript

79
Q

What does an insertion/deletion result in?

A

A frame-shift mutation

80
Q

What is a frame-shift mutation?

A

Everything is moved so all amino acids after mutation is changed

This has a major effect on the structure of the protein produced

81
Q

What is the genome of an organism?

A

It’s entire hereditary information encoded in DNA

82
Q

What is a genome made up of?

A

Genes and other DNA sequences that do not code for proteins

83
Q

What can be determined in genomic sequencing?

A

The sequence of nucleotide bases for individual genes and entire genomes

84
Q

What is used to identify base sequences in genomics and how?

A

Computer programmes by looking for sequences similar to known genes

85
Q

What is bioinformatics?

A

The use of computer and statistical technology to identify DNA samples

86
Q

What is pharmacogenetics?

A

The use of genome information in the choice of drugs

87
Q

Why may an individuals genome be analysed?

A

To predict the likelihood of developing certain diseases

88
Q

What can an individuals personal genome sequence be used to do?

A

Select the most effective drugs and dosage to treat their disease - known as personalised medicine

89
Q

What is a metabolic pathway?

A

When one chemical is changed to another, then to another via a series of enzyme controlled steps

90
Q

What is an anabolic pathway and is energy required?

A

The synthesis of larger molecules from smaller ones

Energy is required

91
Q

What is a catabolic pathway and is energy required?

A

Breakdown of larger molecules down to smaller ones

Energy is released

92
Q

What can the steps in metabolic pathways be?

A

Reversible or irreversible

93
Q

When do alternative routes occur in metabolic pathways?

A

When there is a plentiful supply of one metabolite in a pathway

94
Q

How are metabolic pathways controlled?

A

Each step is driven by a particular enzyme, and a particular gene codes for each enzyme, so as long as the enzyme proteins are correctly functioned, the pathway proceeds

95
Q

What is enzyme action controlled by and regulated by?

A

Controlled by - The presence or absence of particular enzymes

Regulated by - The rate of reaction of key enzymes

96
Q

What do enzymes do?

A

Speed up chemical reactions by lowering the activation energy required for the reactants to reach the transition state

97
Q

What are the active sites of enzymes like?

A

They have a high affinity for substrate molecules and when the two combine, the reactants are orientated to the active site, the activation energy is lowered and the products and released

98
Q

Do the products have a higher or lower affinity for the active site?

A

Lower

99
Q

What is induced fit?

A

The active site is not a rigid structure as when the substrate enters the active site, it changes slightly, making it fit the substrate molecule snugly

100
Q

What happens as the substrate concentration increases?

A

At low concentrations - reaction rate is low due to too few substrate molecules to make full use of all active sites

An increase - increase in reaction rate as more of the active sites are in use

Further increase - no more effect on reaction rate as all the active sites are in use

101
Q

In reversible reactions, what can the presence of substrate do?

A

Drive the direction of the reaction

102
Q

What do inhibitors do?

A

Control metabolic pathways by decreasing the rate of enzyme action

103
Q

What do competitive inhibitors do?

A

Bind to the active site preventing the substrate from binding

This can be overcome by increasing the substrate concentration as there are then a higher chance of enzyme-substrate interaction

104
Q

What do non-competitive inhibitors do?

A

Become attached to a non-active site causing a change in shape of active site and cannot be reversed by increasing substrate concentration

105
Q

What is feedback inhibition?

A

It happens as the concentration of end product builds up and reaches critical concentration, it inhibits an earlier enzyme, blocking the pathway and so prevents further synthesis of the end product

106
Q

What are the 3 stages of cellular respiration?

A

Glycolysis

Citric acid cycle

Electron transport chain

107
Q

What is a duplication mutation?

A

A section of a chromosome is added from its homologous partner

108
Q

What is a deletion mutation?

A

Where a section of chromosome is removed and rest rejoined if needed

109
Q

What is an inversion mutation?

A

A section of chromosome is reversed

110
Q

What is a translocation mutation?

A

A section of a chromosome is added to a chromosome which is not its homologous partner

111
Q

What do substantial changes in chromosome structure do?

A

Make them lethal

112
Q

What are the 4 types of chromosome structure mutation?

A

Duplication

Deletion

Inversion

Translocation

113
Q

What happens during glycolysis?

A

It is a series of enzyme controlled reactions in two stages

Occurs in cytoplasm

Glucose is broken down into pyruvate

Energy investment stage -
ATP required, phosphorylation of glucose and the intermediated

Energy payoff stage -
Involves the direct generation of ATP
Results in a net gain of ATP

114
Q

What happens during the citric acid cycle?

A

Oxygen is required

Pyruvate is broken down to an acetyl group and combines with coenzyme A to produce acetyl coenzyme A

Occurs in the matrix of the mitochondria

The acetyl group from acetyl coenzyme A combines with oxaloacetate to form citrate

During a series of enzyme controlled steps, citrate is gradually converted back into oxaloacetate

The cycle generates ATP and releases carbon dioxide

Dehydrogenaze enzymes remove hydrogen ions and electrons from both glycolysis and citric acid cycle and passes them to the coenzyme NAD forming NADH

The hydrogen ions and electrons from NADH are passed to the electron transport chain

115
Q

What happens in the electron transport chain?

A

The electron transport chain is a series of carrier proteins attached to the inner mitochondrial membrane

The NADH passed its hydrogen ions and electrons down a series of electron acceptors, releasing their energy, which is used to pump hydrogen ions across the inner membrane by active transport

The return flow of hydrogen ions by diffusion via the membrane protein, ATP synthase, drives the synthesis of the bulk of ATP produced in respiration

The final electron acceptor is oxygen, which combines with hydrogen ions and the electrons to form water

116
Q

What is ATP?

A

The high energy compound which transfers energy

117
Q

When is ATP produced?

A

when ADP combines with phosphate in phosphorylation building up energy

118
Q

What is ATP broken down into?

A

ADP and phosphate with energy being released

119
Q

What happens in lactate metabolism?

A

During vigorous exercise, muscled do not get sufficient oxygen to support the electron transport chain so pyruvate is converted into lactate instead of following the normal pathway.

The hydrogen from the NADH produced in glycolysis is transferred to pyruvate in order to produce lactate, regenerating the NAD needed to maintain ATP production during glycolysis.

As lactate builds up in muscles, muscle fatigue occurs and an oxygen debt is built up.

When exercise stops, the oxygen debt is repaid allowing respiration to provide the energy needed to convert lactate back to pyruvate and glucose in the liver.

120
Q

What is pyruvate concerted into during vigorous exercise/lactate metabolism?

A

Lactate

121
Q

What happens as lactate builds up in muscles?

A

Muscle fatigue occurs and an oxygen debt is built up

122
Q

What are the two types of muscle fibres that make up skeletal muscles?

A

Fast twitch

Slow twitch

123
Q

Where do slow twitch rely on ATP from?

A

Respiration

124
Q

Describe slow twitch muscle fibres

A

Contract relatively slow but can sustain the contractions for a long time

Have many mitochondria

Have a large blood supply

Have a high concentration of myoglobin

Major storage fuel is fats

125
Q

What are slow twitch fibres good for?

A

Endurance activities such as long distance running or cycling

126
Q

What does fast twitch rely on for ATP?

A

Glycolysis

127
Q

Describe fast twitch muscle fibres

A

Contract relatively quickly for a short period of time

Have fewer mitochondria

Have a lower blood supply

Major storage fuel is glycogen

128
Q

What are fast twitch fibres good for?

A

Short bursts of activity such as weight lifting or sprinting

Higher Human Biology (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions