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AS Biology - Unit 1 > Unit 1: Section 3 - Cell Structure and Membranes > Flashcards

Unit 1: Section 3 - Cell Structure and Membranes Flashcards

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0
Q

Name two parts of eukaryotic cell that prokaryotic cells don’t have?

A

Nucleus and mitochondria

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1
Q

Are prokaryotic or eukaryotic cells more complex?

A

Eukaryotic cells

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2
Q

Parts of a cell are called ?

A

Organelles

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3
Q

What surrounds a cell?

A

Plasma membrane

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4
Q

What is the function of the plasma membrane?

A

Regulates the movement of substances into and out of the cell

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5
Q

What two things would you find in the nucleus and what surrounds the nucleus?

A

Contains the nucleolus and chromatin, surrounded by the nuclear envelope

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6
Q

What is the nuclear envelope?

A

Double membrane which surrounds the nucleus

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7
Q

What is the function of lysosomes?

A

Contains digestive enzymes to digest invading cells and dead organelles

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8
Q

Where are ribosomes made in the cell?

A

In the nucleolus

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9
Q

Where are proteins made in the cell?

A

In the ribosomes

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10
Q

What are the two types of ER called?

A

Smooth and rough

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11
Q

What’s the function of the nucleus?

A

To control cell activity

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12
Q

What’s the function of the smooth ER?

A

Makes and transports lipids

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13
Q

What’s the function of the rough ER?

A

Processes and transports the proteins which gave been made by the ribosomes

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14
Q

What two organelles would a plant cell have but not an animal?

A

Chloroplasts and a cell wall

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15
Q

What us the function of the Golgi apparatus?

A

Modifies new proteins

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16
Q

What does the Golgi apparatus contain to transport protein in?

A

Vesicles

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17
Q

What in the cells produces energy through aerobic respiration?

A

Mitochondria

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18
Q

Do mitochondria have a single membrane?

A

No double

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19
Q

The inner membrane of a mitochondria fold into?

A

Cristae

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20
Q

What’s the inside of the mitochondria called?

A

Matrix

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21
Q

What will a cell contain more of if it uses a lot of energy ?

A

Mitochondria

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22
Q

What cells line the small intestine?

A

Epithelial cells

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23
Q

What are micro villi?

A

Finger like projections on the villi

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24
Q

Name two adaptations of epithelial cells in the small intestine?

A
  1. ) they have villi and then micro villi on the outside of the cell to increase surface area for food absorption
  2. ) lot of mitochondria to provide more energy energy for active transport
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25
Q

What are red blood cells adapted for and how are they adapted for this?

A

To carry oxygen, by having no nucleus to make room for oxygen-carrying haemoglobin

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26
Q

Name two ways that sperm cells are adapted for their function?

A
  1. ) they contain a lot of mitochondria to provide large amounts of energy
  2. ) they contain enzymes in their head which break down the plasma membrane of the egg cell
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27
Q

What’s the difference between magnification and resolution?

A

Magnification is how much bigger the image is than the specimen where as resolution is how detailed the image is

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28
Q

What’s the formula for magnification?

A

Magnification = length of image / length of specimen

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29
Q

How do you convert millimetres into micrometres?

A

Times by 1000

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30
Q

How do you convert micrometres into millimetres?

A

Divide by 1000

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31
Q

Name the three types of microscopes?

A

Light microscopes, transmission electron microscopes and scanning electron microscopes

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32
Q

How do transmission electron microscopes work?

A

Electromagnets focus a beam of electrons through the specimen, denser parts of the specimen absorb more electrons so they look darker on the image you end up with

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33
Q

How do scanning electron microscopes work?

A

Scan a beam of electrons across a specimen, knocking electrons of the specimen which are gathered by a cathode ray tube to form the image

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34
Q

What are two advantages of a light microscope?

A
  1. ) can see living cells

2. ) can see colour

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35
Q

What are two disadvantages of a light microscope?

A
  1. ) low magnification

2. ) poor resolution

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36
Q

What are two advantages of the transmission electron microscope?

A
  1. ) high magnification

2. ) good resolution

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37
Q

What are two disadvantages of a transmission electron microscope?

A
  1. ) thin specimen so electrons can pass through

2. ) can’t be used on living cells, must be in a vacuum

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38
Q

What are three advantages of a scanning electron microscope?

A
  1. ) 3D image
  2. ) can be used on thick specimen
  3. ) high magnification
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39
Q

What are two disadvantages of a scanning electron microscope?

A
  1. ) can’t be used on living cells, in a vacuum

2. ) lower resolution than a transmission electron microscope

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40
Q

A method of separating organelles from their cells is called?

A

Cell fractionation

41
Q

What are three steps of cell fractionation ?

A
  1. ) homogenisation - breaking up the cell
  2. ) filtration - getting rid of the big bits
  3. ) ultracentrifugation - separating the cells
42
Q

Name two ways cells are broken up during cell fractionation?

A
  1. ) vibrating the cells

2. ) or grinding the cells up

43
Q

During cell fractionation why is homogenisation an important step?

A

Breaks up the plasma membrane and releases the organelles into the solution

44
Q

In cell fractionation why is the solution kept ice cold?

A

To reduce the activity of enzymes that break down the organelles

45
Q

In cell fractionation why is the solution isotonic ?

A

Some concentration of chemicals in the solution as the cells so there’s no net movement of water, to prevent the organelles bursting or shrivelling due to osmosis

47
Q

What happens during filtration in cell fractionation?

A

The solution is passed through a gauze to separate any cell debris from the organelles

48
Q

Why do you have to do ultracentrifugation for cell fractionation?

A

You have a solution containing different organelles and ultracentrifugation separates the organelles from each other

49
Q

What happens during ultracentrifugation?

A

The cell fragments are put into test tube, and then into a centrifuge and spun at high speeds. The heaviest organelles go to the bottom and then are removed in a pellet. This is repeated until you have separated out all the organelles.

50
Q

What order will you find organelles after ultracentrifugation (lysosome, ribosomes, mitochondria, nucleus, ERs)?

A

Nucleus, mitochondria, lysosomes, ERs and finally ribosomes`

51
Q

What is the plasma membranes main function?

A

To control what substances enter or leave the cells

52
Q

What are plasma membrane composed of?

A

Phospholipids, proteins and carbohydrates

53
Q

What is the double layer of phospholipids called?

A

Bilayer

54
Q

Is the head or tail of the phospholipid hydrophobic?

A

Head - hydrophilic

Tail - hydrophobic

55
Q

How does the phospholipid bilayer form a barrier against water soluble substances?

A

They arrange them selves with the heads all facing out and the tail inwards, as this means the centre is hydrophobic the water soluble substances cant get through

56
Q

What does the plasma membrane contain that allows it to detect when chemicals are released from other cells?

A

Receptor proteins

57
Q

What does the plasma membrane contain that allows cell recognition?

A

Glycoproteins and glycolipids on the outside

58
Q

What can fit between the phospholipids to make the bilayer more rigid and less fluid?

A

Cholesterol

59
Q

Describe what a triglyceride looks like?

A

One glycerol molecules with three long tails of hydrocarbons (fatty acids)

60
Q

What are the two types of fatty acid called and where does the difference lie in them?

A

Saturated and unsaturated, in the hydrocarbon tail

61
Q

Whats the difference between saturated and unsaturated fatty acids?

A

Saturated have no double bonds between the carbon atoms, where as unsaturated does

62
Q

What reaction are triglycerides formed by?

A

Condensation reactions

63
Q

What bond forms between glycerol and fatty acids?

A

Ester bond

64
Q

How is triglyceride formed from 3 fatty acids and a glycerol molecules?

A

Each fatty acids bonds with an OH on the glycerol, taking out H20 and leaving just the O between them

65
Q

Whats the difference between phospholipids and triglycerides?

A

Phospholipid only have two fatty acids and instead of the last fatty acid have a phosphate group

66
Q

Is the fatty acid or the phosphate group which is hydrophobic?

A

Phosphate group - hydrophilic

Fatty acid - hydrophobic

67
Q

What is the test called you can do for lipids?

A

Emulsion test

68
Q

How do you do the emulsion test for lipids?

A

Add ethanol to it and then shake it, add it to water and any lipid will show up as a milky emulsion

69
Q

What is diffusion?

A

The net movement of particles from an area of high concentration to an area of lower concentration

70
Q

During diffusion to molecules only move from an area of high concentration to an area of lower concentration??

A

No they move both ways just the net movement is towards the lower concentration

71
Q

What is meant by along the concentration gradient?

A

The path of the molecules from the high concentration to the low

72
Q

What does diffusion is a passive process mean?

A

No energy I needed for it to happen

73
Q

Can oxygen and carbon dioxide diffuse across the phospholipid bilayer?

A

Yes as they are small enough to

74
Q

What three things affect the rate of diffusion and how?

A
  1. ) concentration gradient - steeper the faster the rate of diffusion
  2. ) thickness of exchange surface - thinner the faster the rate of diffusion
  3. ) surface area - larger the faster the rate of diffusion
75
Q

What is osmosis?

A

The diffusion of water molecules across a partially permeable membrane, from an area of high water potential to an area of lower water potential

76
Q

What water potential does water have?

A

zero

77
Q

Why is water potential of a solution always negative?

A

Adding anything to water will lower its water potential, and so it decreases from zero and becomes negative

78
Q

What is isotonic?

A

When two solutions have the same water potential

79
Q

What happens when a cell I placed in a solution with a higher water potential than it?

A

Water will move in my osmosis causing the cell to swell eventually burst

80
Q

What I facilitated diffusion?

A

Net movement of particles from an area of higher concentration to an area of lower concentration using carrier proteins and channel proteins

81
Q

Why do some molecules have to use facilitated diffusion?

A

They are too large to fit through the phospholipid bilayer or they are charged

82
Q

Name two transport proteins?

A

Carrier and channel

83
Q

Do carrier proteins transport large molecules or charged atoms?

A

Large molecules

84
Q

How do carrier proteins transport large molecules?

A

The molecule attaches to the carrier protein in the membrane, the protein changed shape and the molecule is released on the opposite side

85
Q

Are charged particles transported through carrier or channel proteins?

A

Channel

86
Q

How do channel proteins transport charged atoms?

A

They form pores in the membrane for charged atoms to diffuse through

87
Q

What is active transport?

A

Uses energy to move molecules and ions across the plasma membrane, against the concentration gradient

88
Q

What two transports are used in active transport?

A

Carrier and co transporters

89
Q

How are carrier proteins used in active transport?

A

A molecules attaches to it, the protein changes shape and releases the molecule on the opposite side. However energy is needed to move the molecules against the concentration gradient

90
Q

How do co transports transport molecules against the concentration gradient?

A

They bind two molecule at the time. It uses he concentration gradient of one of the molecules to move the other against its own concentration gradient

91
Q

Name two molecules that uses co transporters?

A

Sodium ions and glucose, to transport glucose against the concentration gradient

92
Q

What is the stage 1 absorption of glucose during digestion?

A

When the carbohydrates are first broke down there is a high concentration of glucose in the small intestine so its just moves by diffusion across the epithelial cells and into the blood

93
Q

Why do we have to use both diffusion and active transport to absorb glucose?

A

If we only used diffusion, when the concentrations were equal we wouldn’t absorb the rest of the glucose, active transport allows us to do this

94
Q

How is the concentration gradient of sodium ions increased using the sodium potassium pump?

A

The sodium potassium pump transports sodium ions out of the small intestine epithelial cells and into the blood. Decreasing the concentration of sodium ions in the epithelial cells, and so increasing the concentration gradient

95
Q

Why does the sodium potassium pump need to increase the concentration gradient of sodium in the small intestine?

A

So that it can diffuse along its concentration gradient back to the blood via the co transporters carrying the glucose with it.

96
Q

Is cholera a prokaryotic cell or a eukaryotic cell and why?

A

prokaryote - it is a much simpler, single celled organism

97
Q

What is the flagellum?

A

A long, hair-like structure that rotates to make the bacteria move

98
Q

Why do some bacteria have a capsule?

A

Helps to protect the bacteria from attack by the immune system

99
Q

What does the toxin released by cholera cause the chloride ion protein channels to do and what is the effect of this?

A

It causes the chloride ion protein channels in the small intestine epithelial cells to open
Chloride ions then move into the small intestine, lowering the water potential
Water then moves out of the blood into the small intestine by osmosis
The big increase in water leads to bad diarrhoea and hydration

100
Q

What is an oral rehydration solution?

A

A drink that contains large amounts of salt and sugars dissolved in water to try and treat diarrhoea

101
Q

Why does an oral rehydration solution contain a lt of sodium ions?

A

To increases glucose absorption

102
Q

Give one for and one against for testing new oral rehydration solutions on children

A

For - the disease mainly effects children so it must be shown to be effective in them
Against - children don’t decide if they want to do their parents do so it can be seem to be unfair

AS Biology - Unit 1 (5 decks)

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