Unit 1 Flashcards

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1
Q

A stem cell is an unspecialised cell that can:

A

make copies of itself and differentiate (make copies of itself)

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2
Q

Differentiation occurs when

A

when unspecialised cells become specialised

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3
Q

A differentiated cell only

A

Has a few genes switched on

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4
Q

the 2 types of stem cells are

A

embryonic and adult (tissue)

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5
Q

embryonic stem cells are

A

derived from an embryo

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6
Q

embryonic stem cells have the ability to

A

differentiate into all cell types

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7
Q

Where are adult stem cells found?

A

in small numbers in the tissue and organs of adults and children, including the brain, bone marrow, skeletal muscle and skin

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8
Q

adults stem cells give rise to

A

a more limited range of cell types.

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9
Q

the theraputic uses of stem cells incude:

A

bone marrow transplants
skin graphs for burns
stem cell graphs for cornea repair

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10
Q

stem cell research gives us information including:

A

the study of diseases
drug testing
how the processes of growth, differentiation and gene regulation work

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11
Q

which type of stem cells has ethical issues surrounding it

A

embryonic stem cells

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12
Q

somatic cells are

A

the differentiated cells that form the different types of body tissue

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13
Q

type of somatic cells are:

A
epithelial cells (cover the body surface and  line body cavities)
connectives tissue ( includes blood, bone and cartilage cells)
muscle cells (form muscle tissue)
nerve cells (form nerve tissue)
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14
Q

during growth and repair, somatic cells

A

always divide by mitosis to maintain diploid chromosome number

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15
Q

germline cells include

A

the gametes and the cells that produce gametes (gamete mother cells)

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16
Q

germline cells can divide by mitosis to

A

produce more germline cells

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17
Q

germline cells can also divide by meiosis to

A

produce haploid gametes

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18
Q

if a genetic mutation occurs in a germline cells, it

A

will be passed on to the offspring during sexual reproduction

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19
Q

genetic mutations that occur in somatic cells will

A

not be passed to the offspring, as these cells are not involved in sexual reproduction

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20
Q

Cancer cells continue to

A

reproduce to produce a mass of abnormal cells called a tumor

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21
Q

cancer cells do not

A

respond to regulatory signals that would instruct them to stop dividing

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22
Q

DNA consists of

A

units called nucleotides

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23
Q

Nucleotides are made up of

A

phosphate
base
deoxyribose sugar

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24
Q

there are four different types of

A

nucleotides, depending on the base

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25
Q

certain bases are complementary to

A

each other, this is called the base pairing rule

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26
Q

a pairs with

A

t

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27
Q

g pairs with

A

c

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28
Q

bases in adjacent strands are

A

held together by hydrogen bonds

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29
Q

DNA is held together by a strong chemical bond between

A

the phosphate of one nucleotide and the carbon 3 of the sugar on another nucleotide

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30
Q

the double helix is described as

A

having two anti-parallel chains of nucleotides because one side goes 5’ to 3’ and the opposite side goes 3’ to 5’

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31
Q

the base sequence of a DNA determines

A

the genotype

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32
Q

DNA is arranged in

A

tightly coiled nucleotides

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33
Q

the DNA is packed with

A

proteins

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34
Q

DNA replication occurs in

A

the nucleus and involves DNA unwinding

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35
Q

once the DNA has unwound it

A

unzips to expose its bases

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36
Q

the DNA bases are now

A

used as a template for a new DNA strand to be made

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37
Q

once the nucleotides are exposed, free floating

A

nucleotides in the nucleus join on to their complementary bases

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38
Q

once the nucleotides are lined back up, they

A

join to their partner by hydrogen bonds

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39
Q

the DNA strand forms a

A

sugar phosphate backbone

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40
Q

the DNA strand then

A

Winds back up to form 2 identical double helix’s

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41
Q

each double helix contains

A

one original strand and one “new” strand

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42
Q

DNA polymerase is

A

an enzyme that controls the sugar phosphate bonding

43
Q

DNA polymerase can also

A

add nucleotides to the strand but only add nucleotides to a pre-existing chain

44
Q

for DNA polymerase to work a

A

primer must be present

45
Q

what is a primer?

A

a primer is short sequence of nucleotides at the 3’ end

46
Q

once the fragments are all in place

A

the enzyme ligase jooins the fragment together

47
Q

when copying a long chromosome

A

many replication forks operate simultaneously

48
Q

for DNA replication to occur, the nucleus must contain:

A
DNA (template)
Primers
supply of 4 types of nucleotide
enzymes (both ligase and DNA polymerase)
ATP
49
Q

there are 3 types of RNA:

A
messenger RNA (mRNA)
transfer RNA (mtRNA)
ribosomal RNA (rRNA)
50
Q

RNA is

A

a nucleic acid with a similar structure to DNA

51
Q

the role of RNA is in

A

Producing proteins

52
Q

mRNA is made

A

in the nucleus

53
Q

mRNA carries a copy of

A

the DNA code from the nucleus to the ribosome

54
Q

each tRNA can

A

carry one specific amino acid from the cytoplasm to the ribosome

55
Q

ribosomes are made up of

A

protein and ribosomal RNA

56
Q

RNA is made up of

A

nucleotides

57
Q

nucleotides consists of

A

phosphate
base
robose sugar

58
Q

During protein synthesis

A

RNA bases pair with their complementary bases

59
Q

proteins are made up of

A

joining together amino acids in a specific sequence

60
Q

the order of amino acids is

A

dictated by the order of the bases on the DNA

61
Q

two main stages of protein synthesis

A

Transcription

Translation

62
Q

Transcription occurs in

A

nucleus

63
Q

in transcription, a section of DNA is

A

copied to produce a strand of RNA

64
Q

in stage one of transcription,

A

the section of DNA which codes for the desired protein unwinds and unzips

65
Q

in stage two of transcription

A

Free mRNA nucleotides enter the nucleus and RNA polymerase joins them with their complimentary DNA base starting at 3’ end. only one strand of DNA is copied

66
Q

the strand of mRNA produced by transcription is called a

A

Primary transcription

67
Q

Primary transcription contains

A

regions which code for the production of of the protein called extrons and regions which are non coding which are called introns.

68
Q

the introns must

A

be removed before translation can occur

69
Q

Translation is

A

the synthesis of a protein in the form of a polypeptide chain

70
Q

the strand of mRNA is

A

divided into triplet bases called codons

71
Q

each codon contains

A

the code for one amino acid

72
Q

tRNA’s function is

A

to pick up a specific amino acid and bring it to the mRNA on the ribosome

73
Q

the structure of tRNA

A

the anticodon is composed of a triplet of bases which are cfomplementary to an mRNA codon

74
Q

the amino acid binding site can

A

only pick up one specific amino acid

75
Q

translation occurs in

A

ribosome

76
Q

AUG is the

A

Start codon. this indicates to the tRNA where to add the first amino acid

77
Q

complementary anticodons pair with

A

their complementary codon ensuring the amino acids are in the right sequence

78
Q

the amino acids join together by

A

a peptide bond to form a polypeptide chain

79
Q

Stop codons

A

indicate to the tRNA where to stop adding amino acids

80
Q

Different mRNA molecules are produced from

A

the same primary transcription depending on which segments are treated as exons and which are treated as introns

81
Q

after translation the polypeptide chain can be modified to produce many different proteins

A

the polypeptide chain can be cut and combined with other polypeptides
a phosphate or carbohydrate group ca n be added to the polypeptide chain

82
Q

types of protein: fibrous

A

collagen
elastin
keratin

83
Q

types of protein: globular

A

enzymes
antibodies
hormones

84
Q

types of protein: conjugated

A

chlorophyll

haemoglobin

85
Q

your phenotypes are determined by

A

the protein you produce

86
Q

the protein you produce are controlled by

A

the gene being expressed

only a fraction of the genes in a cell are expressed

87
Q

gene epression can be influenced by

A

intra-cellular and extra-cellular environmental factors

88
Q

gene expression is controlled by

A

the regulation of transcription and translation

89
Q

a mutation is

A

a change to a individuals DNA

90
Q

there are two types of mutation

A

Gene Mutation

chromosome mutation

91
Q

mutations are

A

the only source of new variation

92
Q

mutations frequency can be increase

A

by mutagenic agents

93
Q

examples of mutagenic agents

A

chemicals (mustard gas)

radiation (UV lights)

94
Q

gene mutation involves

A

a change in the sequence of nucleotides

95
Q

this can be by

A

substitution, deletion or insertion of nucleotides

96
Q

a substitution mutation involves

A

a change In one nucleotide in the DNA sequence of a single gene

97
Q

substitution mutation results In

A

one codon for one amino acid being altered

98
Q

substitutions include

A

missense
nonsense
splice - site mutations

99
Q

missense mutation changes the

A

codon for an amino acid so that a different acid is inserted

100
Q

an example of a disorder that results from missense mutation

A

sickle cell anemia

101
Q

nonsense mutation results in

A

a codon for a specific amino acid being changed to a stop codon

102
Q

nonsense mutation causes

A

protein synthesis to stop early and results in a shorter protein which is unable to function

103
Q

Splice - site mutation

A

mutations in the area