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Biology additional edexcel > B2.1 The building blocks of cells > Flashcards

B2.1 The building blocks of cells Flashcards

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1
Q

What does a light microscope do?

A

It magnifies an object

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2
Q

What does the cell membrane do?

A
  • separate the contents of the cell from its surroundings

- controls the movement of substances into and out of the cell

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3
Q

What process happens in the cytoplasm?

A

Respiration

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4
Q

What are the seven life processes?

A

Movement
Respiration
Sensitivity

Growth
Reproduction
Excretion
Nutrition

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5
Q

What does the nucleus do?

A

Control the activities of the cell

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6
Q

What happens in the mitochondria?

A

Respiration

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7
Q

What does the cell wall do?

A

Support the cell and allow it to keep its shape

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8
Q

What are plant cell walls made of?

A

Cellulose

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9
Q

What is the vacuole?

A

A space in the cytoplasm that is filled with cell sap

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10
Q

What does the vacuole do?

A

Helps support the plant by keeping the cells rigid

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11
Q

What does a chloroplast do?

A

Absorbs light energy to be used in photosynthesis

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12
Q

What green substance does the chloroplast use to absorb light energy?

A

Chlorophyll

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13
Q

What is the word equation for photosynthesis?

A

carbon dioxide + water (+ light energy) → glucose + oxygen

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14
Q

What is the magnification of a light microscope?

A

x1500

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15
Q

What is the magnification of an electron microscope?

A

x2,000,000

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16
Q

Do bacteria have a nucleus?

A

No

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17
Q

What two types of DNA do bacteria contain?

A
  • Chromosomal DNA

- Plasmid DNA

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18
Q

What is the giant loop of DNA that carries most of the genetic material in a bacterial cell called?

A

Chromosomal DNA

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19
Q

What type of DNA comes in small loops and carries extra genetic information in a bacterial cell?

A

Plasmid DNA

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20
Q

What are flagella?

A

Long whip-like structures that the bacteria can use to move themselves along

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21
Q

Where are chromosomes found?

A

The nucleus

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22
Q

What are chromosomes made up of?

A

A string of genes

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23
Q

What do genes contain instructions for?

A

Amino acids

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24
Q

What is a gene made up of?

A

A length of DNA

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25
Q

What causes genetic disorders?

A

A faulty allele

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26
Q

What is gene therapy?

A

Replacing or mending faulty genes that cause a disorder

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27
Q

What is genetic engineering?

A

The removal of a gene from one organism and inserting it into the DNA of another

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28
Q

What does GMO stand for?

A

Genetically modified organism

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29
Q

What are some advantages of genetically modified bacteria producing insulin?

A
  • Can be used by vegans (used to be extracted from dead cattle and pigs)
  • supply of insulin is not affected by animal diseases or the number of animals slaughtered for meat
  • by using bacteria in fermenters insulin can be made cheaply in vast quantities
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30
Q

What is a disadvantage of genetically modified bacteria producing insulin?

A

Bacteria produce insulin slightly differently so it does not suit everyone because of minute differences

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31
Q

Why do humans need beta-carotene?

A

To produce vitamin A

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32
Q

What are the effects of a lack of vitamin A?

A
  • the immune system doesn’t work properly which may cause death
  • may cause blindness
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33
Q

Why are some people concerned about GM foods?

A
  • believe it might crossbreed and contaminate the original DNA of the plant
  • worry it might harm people
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34
Q

What are some disadvantages of genetically modified food?

A
  • expensive

- some don’t produce fertile seed

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35
Q

What are some disadvantages of making herbicide resistant crops?

A
  • the development of herbicide resistant weeds because of cross-pollination with wild plants
  • there may be a loss of biodiversity as fewer weeds survive, meaning loss of food and shelter for animals
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36
Q

How many chromosomes do human diploid cells contain?

A

46 (2 pairs of 23)

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37
Q

When is mitosis used?

A

During growth or to replace damaged cells

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38
Q

What is DNA replication?

A

Chromosomes making copies of themselves

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39
Q

How do you produce two daughter cells?

A

Through the division of a parent cell

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40
Q

How many cells does mitosis produce?

A

Two

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41
Q

How many cells does meiosis produce?

A

Four

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42
Q

What process is used in the asexual reproduction of bacteria?

A

Mitosis

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43
Q

What is produced when two gametes fuse during fertilisation?

A

A diploid cell called a zygote

44
Q

What is a zygote that develops into a ball of cells called?

A

An embryo

45
Q

How many chromosomes does a haploid cell have?

A

23

46
Q

Does meiosis or mitosis produce genetically identical cells?

A

Mitosis

47
Q

What are clones?

A

Individuals that are genetically identical

48
Q

What is a way of producing cloned animals?

A

Nuclear transfer

49
Q

What does enucleated mean?

A

Something that has had its nucleus removed

50
Q

What happens during nuclear transfer?

A
  • the nucleus of a body cell is put into an enucleated egg cell
  • it is stimulated to start dividing to form an embryo. -it is then implanted into the uterus of the surrogate mother
51
Q

How is a cell stimulated to start dividing into an embryo during nuclear transfer?

A

Through electric pulses

52
Q

What are embryonic stem cells?

A

Cells from an embryo in the early stages of division that can differentiate into almost any type of cell

53
Q

What two things can happen when a stem cell divides?

A

It can produce more stem cells or it can produce specialised or differentiated cells

54
Q

What is the difference between adult stem cells and embryonic stem cells when they differentiate?

A

Adult stem cells can only differentiate into a few types of cells while embryonic stem cells can in develop into almost any type of human cell

55
Q

What is a way of collecting embryonic stem cells?

A

Using leftover embryos created for couples having fertility treatment

56
Q

Why is the use of embryonic stem cells controversial?

A

When embryonic stem cells are extracted the embryo is killed

57
Q

What is a bone marrow transplant used for?

A

Treating leukaemia

58
Q

What happens during a bone marrow transplant?

A

The patient’s white blood cells are destroyed and adult stem cells from someone else are put into the patient. These stem cells then multiply and produce new healthy white blood cells

59
Q

Why can a bone marrow transplant not work?

A

The body can reject the cells and destroy them if they are too different

60
Q

How does cloning help solve the problem of the body rejecting foreign cells from a bone marrow transplant?

A

If you make a cloned embryo of the patient you can use the embryonic stem cells to make white blood cells. These won’t be rejected because the body will recognise them as their own cells

61
Q

Why can a treatment with stem cells be dangerous?

A

The stem cells may produce the wrong kind of cell or create cancer cells

62
Q

What forms genetic code?

A

The order of bases on a DNA strand

63
Q

What are the names of the four bases found in DNA?

A

Adenine, cytosine, guanine and thymine

64
Q

How many different amino acids are there in human proteins?

A

20

65
Q

What do chains of amino acids form?

A

Proteins

66
Q

What is protein synthesis?

A

The process of using the sequence of bases in DNA to form amino acids which build chains to form proteins

67
Q

What two processes are used when making a protein?

A

Transcription and translation

68
Q

Where does transcription take place?

A

Inside the nucleus

69
Q

What is messenger RNA (mRNA)?

A

A strand of bases that are complementary to the original DNA strand

70
Q

What is transcription?

A

The process of the DNA in a gene unzipping and mRNA being created based on a strand

71
Q

How does the DNA in a strand unzip?

A

Weak hydrogen bonds between bases are broken

72
Q

What is the difference between RNA and DNA?

A

RNA:

  • only has one strand instead of two
  • has a base called uracil instead of thymine
  • is small enough to move out of the nucleus into the cell’s cytoplasm
73
Q

What does the ribosome do?

A

It moves from one end of the mRNA strand to the other decoding the bases in groups of three

74
Q

What is another name for a base triplet?

A

A codon

75
Q

What does transfer RNA (tRNA) do?

A

It brings complementary bases to line up with the codon, and releases an amino acid to join the chain

76
Q

What happens when the ribosome decodes the whole mRNA strand?

A

A chain of amino acids is formed

77
Q

What is a polypeptide?

A

A chain of amino acids

78
Q

What do polypeptides do to form a protein?

A

They fold, twist and may link up with other polypeptides

79
Q

What is a mutation?

A

A change in the sequence of bases in the genetic code

80
Q

What part of the cell are organelles found in?

A

The cytoplasm

81
Q

What is the complementary base of adenine?

A

Thymine

82
Q

What is the complementary base of cytosine?

A

Guanine

83
Q

What holds complementary base pairs together?

A

Weak hydrogen bonds

84
Q

What is a genome?

A

All of the genes found in an individual

85
Q

What did the Human Genome Project find out?

A

The order of 3 million base pairs that make up the human genome

86
Q

What could the discovery of the human genome be used to develop?

A
  • improved testing for genetic disorders
  • new ways of finding genes that increase the risk of certain diseases
  • new treatments and cures for disorders
  • seeing how humans have evolved
  • personalised medicines
87
Q

What type of cells are gametes?

A

Haploid

88
Q

When is meiosis used?

A

During reproduction

89
Q

What are the drawbacks of cloning mammals?

A

Very few develop successfully

90
Q

How many bases are there in a codon?

A

Three

91
Q

What causes the shape of an enzyme?

A

It’s amino acid sequence

91
Q

What is a catalyst?

A

A substance that speeds up the rate of a reaction without being used up itself

91
Q

What is an enzyme?

A

A biological catalyst

92
Q

What is digestion?

A

The breaking down of larger molecules into smaller ones

93
Q

What is synthesis?

A

The joining of smaller molecules to make larger ones

94
Q

What are substrate molecules?

A

The molecules that enzymes work on

95
Q

What happens when temperature is above or below the optimum temperature of an enzyme?

A

The rate of reaction slows down

96
Q

What affects the rate of reaction of an enzyme?

A
  • temperature
  • pH
  • substrate concentration
97
Q

What does it mean when an enzyme is highly specific for a substrate?

A

It only works for that one substrate

98
Q

What do carbohydrases break down?

A

Carbohydrates

99
Q

What do proteases break down?

A

Proteins

100
Q

What is the active site of an enzyme?

A

The place on an enzyme that has a special shape in order to hold the substrate molecule during a reaction

101
Q

What is the lock-and-key hypothesis?

A

A hypothesis that says that enzymes only work when a certain substrate fits perfectly into the active site

102
Q

What affects the shape of an active site of an enzyme?

A

Temperature and pH

103
Q

What happens to an enzyme when temperature or pH are too extreme?

A

The enzyme denatures and the active site is destroyed

104
Q

What is denaturation?

A

A change in the characteristics of a protein through heat, acidity or other factors that don’t allow it to do its job

105
Q

What are amino acids used to make?

A

Proteins

Biology additional edexcel (3 decks)

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