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S3 exams > Biology > Flashcards

Biology Flashcards

1
Q

What is an organelle

A

A structure which Carrie sour a certain function in a cell

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2
Q

What is the function of a cell wall and where is it found

A

It supports, strengthens and maintains the shape of the cells and is found in bacterial, fungal and plant cells

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3
Q

What is the function of a mitochondria and where is it found

A

It is the site of aerobic respiration in the cell and is found in plant, animal and fungi cells

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4
Q

What is the function of chloroplasts and where can they be found

A

Site of photosynthesis and is found in some plant cells

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5
Q

What is the function of the cell membrane and where is it found

A

To control entry and exit of substances and is found in plant, bacterial, fungi and animal cells

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6
Q

What is the function of the sap vacuole and where is it found

A

Stores water, sugar and salts and can be found in plant cells

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7
Q

What is the function of the nucleus and where can it be found

A

Controls the cell’s activities and stores it’s genetic information. Can be found in plant, fungi and animal cells

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8
Q

What is the function of the ribosomes and where are they found

A

Site of protein synthesis and are found in plant, animal,fungi and bacterial cells

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9
Q

What is the function of plasmids and where are they found

A

They code for a few proteins and are only found in bacterial cells as they have no nucleus

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10
Q

What is the function of the cytoplasm and where is it found

A

Site of all biochemical reactions and found in animal, plant, bacterial and fungi cells.

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11
Q

What is unique about plant cell walls

A

They are made of cellulose compared to other cells which have membranes made of other materials.

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12
Q

What is the structure of a cell membrane and what does this mean

A

Constantly moving Phospholipid bilayer with proteins which allow some substances to pass through with ease, making it selectively permeable

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13
Q

What is passive transport

A

The movement of molecules or ions down a concentration gradient from an area of high to low concentration. No energy input is required. Diffusion is an example of passive transport

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14
Q

What is osmosis

A

The movement of molecules down a concentration gradient from a high to low concentration through a selectively permeable membrane. Doesn’t require energy input

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15
Q

What is the effect of osmosis on a typical animal cell

A

It will shrink or burst depending on the inner and outer concentrations. This happens as they have no cell wall to prevent them from bursting.
Burst if higher concentration outside
Shrink if higher concentration inside

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16
Q

What is the effect of osmosis on a typical plant cell

A

It will become turgid or plasmolysed as it has a cell wall to prevent it from bursting
Plasmolysed if higher concentration inside
Turgid if higher concentration

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17
Q

What is active transport

A

The movement of molecules or ions up a concentration gradient from a low to higher concentration. Energy input is required in the form of ATP. Cells which use active transport have many mitochondria due to this.

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18
Q

What is DNA

A

DNA is a molecule found in all living cells, in the nucleus in plant, animal and fungi cells but in ring-like structures called plasmids in bacterial cells.

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19
Q

What is the purpose of DNA

A

Contains genetic information our body needs to produce proteins, which then decide your physics, characteristics.

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20
Q

What is the structure of DNA

A

A doubled stranded helix, with two sugar-phosphate backbones that curve around each other and are held together by complementary base pairs.

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21
Q

What are the variables in DNA

A

Bases
The four bases are: adenine, thymine, guanine and cytosine. (A,T,G,C)
They pair together as: A-T
G-C

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22
Q

What does the order of bases determine

A

Sequence of amino acids which then codes for a specific protein.

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23
Q

What is mRNA

A

A molecule that makes a complementary copy of a strand of DNA and then takes it too the ribosome as the DNA molecule is too large to leave the nucleus.

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24
Q

What happens in the ribosomes once the mRNA has arrived

A

The base sequence codes for amino acids - three bases codes for one amino acid - the sequence of these acids then codes for the particular protein, depending on how the chain of acids fold (polypeptide chain).

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25
Q

What functions do proteins have

A 
Enzymes
Structural
Antibodies
Hormones
Receptors
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26
Q

What are antibodies and what do they do

A

They are a type of protein which provides your body defence against bacteria and viruses by binding to them so that white blood cells can recognise and destroy them

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27
Q

What are receptors and what do they do

A

They are a type of protein which allows cell to recognise specific chemical signals

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28
Q

What are hormones and what do they do

A

They are a type of protein which is used as a chemical messenger which is transported in the blood.

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29
Q

What do structural proteins do

A

They provide strength and support for cell structures

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30
Q

What are enzymes and they’re key characteristics

A 
Biological catalysts
Made in all living cells
Speed up chemical reaction within a cell
Proteins
Unchanged in the process so can be reused
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31
Q

What is enzyme specificity

A

The fact that only one substrate works with a specific substrate.

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32
Q

Why are enzymes specific to one substrate

A

As they have complementary active sites - where enzymes bind to substrates - which are specific to only one another.

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33
Q

An example of an enzyme reaction is

A

HPCOW

Hydrogen peroxide —-catalase—-> oxygen + water

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34
Q

What are the two main types enzyme controlled reactions

A

Degradation- when one substance is broken down into two or more.
Synthesis- when two or more substances are bound together to form one substance

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35
Q

An example of a synthesis reaction is

A

Glucose-1-phosphate—-phosphorylase——> starch

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36
Q

An example of a degradation reaction is

A

HPCOW

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37
Q

What is optimum temperature and the effect of too Hugh temperatures on an enzyme.

A

Optimum temperature is the temperature at which an enzyme work the fastest.
Too high temperatures denatures the protein changing the shape of it meaning it is no longer complementary to its substrate

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38
Q

What is an enzymes optimum pH and what happens when it isn’t in its optimum range

A

An enzymes optimum pH is the pH at which it works the fastest.
If it isn’t in its pH range it will become denatured and will no longer be complementary to its substrate i.e. too high or too low pH.

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39
Q

What can denaturing be described as

A

Irreversible

40
Q

What is genetic engineering

A

The artificial transfer of genetic information from one cell to another

41
Q

What is genetic engineering controlled by

A

Enzymes

42
Q

What is the first stage of genetic engineering

A

The desired gene is identified in the source cell or chromosome

43
Q

What is the second stage of genetic engineering

A

The required gene is extracted from the DNA using enzyme ‘scissors’

44
Q

What is the third stage of genetic engineering

A

The plasmid from the target bacterial cell is extracted

45
Q

What is the fourth stage of genetic engineering

A

The required gene is inserted into the extracted plasmid by cutting out a section of the plasmid using enzyme ‘scissors’

46
Q

What is the fifth stage of genetic engineering

A

Replace the modified plasmid into the target cell and grow it in ideal conditions so that it reproduces. Then the required gene can be gathered and extracted in mass.

47
Q

What is respiration

A

The process by which energy is released through the breakdown of glucose in substances. It is enzyme controlled.

48
Q

What is the general formula of respiration

A

Glucose —-enzymes—-> waste products + energy

49
Q

What is released with the waste products due to respiration

A

Energy in the form of ATP, which can then be used as an immediate source of energy.

50
Q

What cellular activités require energy input in the form of ATP

A

Muscle cell contraction
Cell division
Protein synthesis
Transmission of nerve impulses

51
Q

What must be present for aerobic respiration to occur and where does aerobic respiration occur.

A

Oxygen

Mitochondria

52
Q

What is the first stage of aerobic respiration

A

The breakdown of glucose into two molecules of pyruvate.
2 molecules of ATP are also produced in the reaction from 2ADP + 2Pi
Occurs in cytoplasm
Doesn’t require oxygen

53
Q

What is the second stage of aerobic respiration

A

The breakdown of two molecules of oyruvate into carbon dioxide and water. 36 molecules of ATP are also produced from 36ADP + 36Pi
Occurs in mitochondria
Oxygen is present/needed.

54
Q

How many molecules are produced in aerobic respiration overall

A

38

55
Q

What is fermentation

A

The breakdown of glucose without oxygen

56
Q

What happens in fermentation

A

Glucose is broken into pyruvate, producing 2ATP molecules in the process from 2ADP + 2Pi.
Occurs in cytoplasm
No oxygen required

57
Q

What is pyruvate converted into in plant cells during fermentation

A

Ethanol and carbon dioxide

58
Q

What is pyruvate converted into in animal cells, during fermentation

A

Lactate (lactic acid)

59
Q

What can be concluded of fermentation against aerobic respiration

A

Fermentation is much less efficient than aerobic respiration as it produces much less energy.

60
Q

What can the conversion of pyruvate into lactate or carbon dioxide and ethanol, during fermentation be known as

A

An irreversible reaction

61
Q

What is the importance of cell division in multicellular organisms

A

Growth
Repair of damaged cells
Replace dead cells

62
Q

What is the importance of cell division in unicellular organisms

A

Asexual Reproduction

63
Q

What is the centre of a chromosome called

A

Centromere

64
Q

What are the two separate strands that make up chromosomes called

A

Chromatids

65
Q

What is mitosis

A

The production of new body cells by cell division

66
Q

What is the first stage of mitosis

A

The chromosomes coil up and condense and then appear as two identical chromatids held together by a centromere.

67
Q

What is the second stage of mitosis

A

The chromosomes line up at the equator of the cell and the spindle fibres begin to form from the opposite poles of the cell.
The nuclear membrane also breaks down.

68
Q

What is the third stage of mitosis

A

The chromatids are then pulled apart by the spindle fibres and pulled to opposite poles of the cell.

69
Q

What is the fourth stage of mitosis

A

The cytoplasm divides leaving two separate cells.
Now called chromosomes again
2 daughter cells
Genetically identical as no genetic information is lost
Nuclear membrane and cell membrane reform

70
Q

What does mitosis do

A

Maintains the chromosome complement (46 in humans, 23pairs). This means that I generic information is lost.

71
Q

Stem cells are…

A

Undifferentiated cell’s which divide for either:

  • differentiation
  • self renewal
72
Q

Two types of stem cells are…

A

Embryonic

Tissue

73
Q

What can embryonic stem cells do..

A

Produce all the cells in your body regardless of what type they already are.

74
Q

What can tissue stem cells do..

A

They produce a limited number of cell types. For example blood stem cells can only make other types of cell in your blood.

75
Q

What are some ethical issues with stem cells

A

Destroys embryos and potential human life

76
Q

Red blood cells have…

A

+ bi-concave shape
+ increases surface area, more space for oxygen and haemoglobin
+ full of haemoglobin to carry oxygen
+ no nucleus so more space for oxygen

77
Q

Root hair cells have…

A

+ a large surface area

+ allows more water and nutrients to be absorbed by the cell, allowing the hair to grow

78
Q

What is the sequence of organisation in humans

A

Cell-> tissue-> organ -> organ system -> organisms

79
Q

What are tissues

A

A group of cells

80
Q

What are organs

A

A group of tissues

81
Q

What are organ systems

A

A group of organs

82
Q

What are organisms

A

A group of organ systems

83
Q

What is the CNS made up of

A

Brain

Spinal cord

84
Q

What does the CNS do

A

Processes information from the senses

Send impulses to bring about a response

85
Q

The flow of information goes

A

Stimulus-> receptors-> sensory neurone-> CNS-> motor neurone-> effectors-> response

86
Q

A reflex arc is…

A

An internal system to prevent the body from harming itself. It goes through the same process as the previous card but instead of going to the brain it only goes to the spinal cord which makes it quicker

87
Q

What is a synapse

A

A gap between two neurons which is crossed by the triggering of chemical which diffuse across the gap and trigger the next impulse.

88
Q

What is the function of the cerebrum and where is it

A

Center of: conscious thought
Memory
Logic/creativity

Located at the top section of the brain

89
Q

What is the function of the cerebellum and where is it located

A

Controls balance and coordination of movement. It is at the bottom right of the brain

90
Q

What is the function of the medulla and where is it located

A

Controls heart and breathing rate.

Located at the bottom of the brain and looks like a tube

91
Q

What is the function of the pituary gland and where is it located

A

Releases hormone and is situated at the bottom left of the brain

92
Q

How could hormones be described

A

Specific to their substrate as they are complementary to each other at their binding site.

93
Q

What happens if blood glucose is too high or low

A

REVISE DIAGRAM

94
Q

What happens if you have type 1 diabetes

A

Your body doesn’t produce insulin and you must therefore inject insulin into your blood stream.

95
Q

What happens if you have type 2 diabetes

A

Your body cells no longer responds to insulin and you must therefore control your diet and exercise.

96
Q

If blood glucose is too high…

A

Insulin released
Liver coverts glucose to glycogen
Blood sugar falls

97
Q

If blood glucose is too low…

A

Glucagon released
Liver converts glycogen to glucose
Blood sugar rises

S3 exams (5 decks)

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