Paper 1: Topic 1 Cell Biology - Cell Structure (IV form) Flashcards

1
Q

Arrange these terms in order of size from smallest to largest: organism tissue organ cell molecule organelle organ system

A

molecule → organelle → cell→ tissue → organ → organ system → organism

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2
Q

Define a cell

A

The simplest living unit of all life forms

e.g. guard cell, goblet cell

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3
Q

Define a tissue and give an example of an animal tissue and a plant tissue

A

An collection of similar cells working together to carry out a specific function

Examples:

  1. animal tissue: ciliated epithelium, connective tissue, muscle tissue and nervous tissue
  2. plant tissues: xylem, phloem
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4
Q

Define an organ and give an example of an animal organ and a plant organ (3)

A

A collection of different tissues working together to carry out specific functions

Examples:

  1. animal organs : stomach, pacreas, eye, skin, liver, heart
  2. plant organs: leaf, flower, root
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5
Q

Define an organ system

A

A collection of different organs working together to carry out specific functions

E.g. digestive system consists of stomach, pancreas, small and large intestine

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6
Q

Define the term differentiation

A

As a cell differentiates it acquires different sub-cellular structures to enable it to carry out a certain function.

It has become a specialised cell.

Changes can include structural changes, chemical changes and changes to the number and type of organelles present in the cell.

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7
Q

Define the term magnification

A

The number of times bigger an image is compared the actual size of the specimen

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8
Q

Define the term resolution

A

The ability to distinguish between 2 separate points

The greater the resolution the sharper and clearer an image will appear

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9
Q

Describe an inhibition zone

A

An area where no bacteria are found to be living on an agar plate

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10
Q

Describe the differences in the genetic material in a prokaryotic cell and a eukaryotic cell

A

Prokaryotic cell:

genetic material is not enclosed in a nucleus

it is a single DNA loop and there may be one or more small rings of DNA called plasmids

Eukaryotic cell:

genetic material is found enclosed in a nucleus

there is more DNA in eukaryotic cells

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11
Q

Electron microscopes allow scientists to study the internal detail of some organelles. Give 2 organelles that this applies to.

A

Mitochondria

Chloroplasts

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12
Q

Give 2 ways in which a muscle cell is specialised for function?

A

Cells contain many mitochondria (to produce ATP which is used by the cell the make the muscle contract)

Contains special proteins in the cytoplasm that can move (to enable the muscle to contract)

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13
Q

Give 2 ways in which equipment can be sterilised when making an agar plate

A

Use disinfectant

Heat treatment

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14
Q

Give 3 examples of specialised cells found in animals

A

Red blood cell (found in the blood)

Motor neurone (found in the nervous system)

Cardiac muscle cell (only found in the heart)

Ciliated epithelial cells (found in the trachea, bronchi and bronchioles)

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15
Q

Give 3 examples of specialised cells found in plants

A

root hair cell (in the root TIPS)

guard cell (in the lower epidermis)

palisade mesophyll cell (in the leaf)

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16
Q

Give 3 ways in which a sperm cell (spermatocyte) is specialised for function?

A

Head only contains half the number of chromosomes in the nucleus (to enable the chromosome number to be kept correct after fertilisation)

Middle part of the cell has many mitochondria (to produce ATP used by the cell to enable it to swim)

Tail is a long extension to the cell (to enable it to move by propulsion)

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17
Q

Give 3 ways in which phloem cells are specialised for function?

A

End walls of cells are broken down (to link adjacent cells)

High number of mitochondria (to produce ATP for translocation)

The cytoplasm of adjacent cells is connected to allow passage of sucrose between cells (think about translocation!)

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18
Q

Give 4 ways in which a motor neurone is specialised for function?

A

Long extended cytoplasm and cell membrane (to form the axon)

Cell body has many extensions (to form dendrites)

Axon is covered in myelin sheath (to increase the speed that the nerve impulse travels)

Contains neurotransmitter chemicals (to enable the impulse to be passed to the effector)

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19
Q

Give 4 ways in which a red blood cell (erythrocyte) is specialised for function?

A

Shape is a biconcave disc (to increase the surface area to volume ratio to take up more oxygen by diffusion)

Biconcave shape also allows RBC to squeeze through the capillaries

No nucleus or mitochondria (to enable it to form a biconcave shape)

Contains a special protein called haemoglobin (to bind with oxygen to form oxyhaemoglobin

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20
Q

Give 4 ways in which the root hair cell is specialised for function?

A

Long extension to the cell wall, cell membrane and cytoplasm (to increase its surface area)

Thin cell wall (to reduce the distance water has to travel to enter the cell by osmosis)

Large permanent vacuole (to hold more water)

High number of mitochondria (to produce ATP for active uptake on mineral ions from the soil)

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21
Q

Give 5 ways in which xylem cells are specialised for function?

A

Thick cell wall (to strengthen the cell)

Cells are dead (to form hollow tubes)

Pits occur between cells (to link adjacent cells)

No organelles (to enable cells to become hollow)

Cells have a layer of lignin around them (to make them waterproof)

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22
Q

Give an example of an organ system in a plant and an animal

A

Plant organ systems = root system, shoot system

Animal organ systems = digestive system, reproductive system, circulatory system

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23
Q

How are inhibition zones used?

A

To determine which antibiotic is most effective at killing bacteria.

The antibiotic which results in the largest inhibition zone is the most effective at killing the bacteria

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24
Q

How can you calculate the actual size of the specimen?

A

Image size divided by magnification

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25
Q

How can you calculate the image size?

A

Actual size of the specimen multiplied by the magnification

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26
Q

How can you calculate the magnification of an image?

A

Image size divided by the actual size of the specimen

HINT: both sizes must be in the same units

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27
Q

How can you prevent contamination when setting up an agar plate to grow bacteria?

A

Sterilise the petri dish and culture medium

Inoculating loops used to transfer microorganisms to the media must be sterilised by passing them through a flame

Partially tape the lid of the petri dish to the base (do not fully tape it as this will prevent oxygen entering and the bacteria will die!)

Incubate the petri dish upside down (at 25oC for 48 hours)

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28
Q

How did electron microscopes help Biologists in their studies?

A

This means that it can be used to study cells in much finer detail.

This has enabled biologists to see and understand many more sub-cellular structures.

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29
Q

How do bacteria reproduce?

A

Bacteria multiply by simple cell division (binary fission) as often as once every 20 minutes if they have enough nutrients and a suitable temperature.

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30
Q

How do you calculate the TOTAL magnification when using a light microscope?

A

Total magnification = eye piece objective magnification x objective magnification

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31
Q

How do you convert micrometres to millimetres?

A

Divide by 1000

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32
Q

How do you convert millimetres to micrometres?

A

multiply by 1000

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33
Q

How does an autoclave work?

A

It sterilises equipment

By using steam at high pressure

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34
Q

How does differentiation differ in animal cells and plant cells?

A

Most types of animal cell differentiate at an early stage.

However, many types of plant cells retain the ability to differentiate throughout life.

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35
Q

How is differentiation different in animal cells compared to plant cells?

A

The ability to differentiate is lost very early in animal cells.

However, plant cells do not lose this ability.

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36
Q

How would you calculate the area of a circle?

A

Area = π r2

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37
Q

If you want to observe a living specimen which type of microscope must you use?

A

Light microscope

You can not use an electron microscope as EMs requires the specimen to be placed in a vacuum so only dead specimens can be observed

38
Q

Name 2 sub-cellular structures that can be seen with an electron microscope but not a light microscope.

A

Ribosomes

Plasmids

39
Q

Other than plant cells which other cells have a rigid cell wall and chloroplasts?

A

Algae e.g. seaweed

40
Q

Plant cell walls and algal cell walls are both made from the same chemical. What is this chemical?

A

Cellulose

41
Q

What are plasmids?

A

Extra pieces of DNA found inside bacteria

They are small circular strands of DNA

42
Q

What are the 2 different types of organism?

A

Unicellular - an organism that consists of one cell

Multicellular - an organism that consists of many cells arranged into tissues, organs and organ systems

43
Q

What are the key features of a scanning electron microscope?

A

It uses a narrow beam of electrons

It produces a 3D image

It provides details of the surface of the specimen

It produces a black and white image (but this can be computer enhanced to produce a colour image)

44
Q

What are the key features of a transmission electron microscope?

A

It uses a wide beam of electrons

It produces a 2D image

It provides internal details of the specimen

It produces a black and white image (but this can be computer enhanced to produce a colour image)

45
Q

Name the two types of electron microscope?

A

Scanning electron microscope

Transmission electron microscope

46
Q

What is a colony?

A

A large number of bacteria growing in close contact with each other

47
Q

What is a culture medium?

A

A liquid (broth) or solid (agar) which contains carbohydrates, minerals, proteins and vitamins that are used by bacteria to grow

48
Q

What is a disinfectant?

A

A chemical that is applied to surfaces, equipment and other NON-living objects.

49
Q

What is a eukaryotic cell?

A

A complex cell which contains many different types of organelles

50
Q

What is a flagellum?

A

A long extension to a bacterium which helps it move (by propulsion)

51
Q

What is a prokaryote?

A

A single-celled organism e.g.bacterium

52
Q

What is a prokaryotic cell?

A

A small and simple cell which does not have a ‘true’ nucleus

53
Q

What is an antiseptic?

A

A chemical that can be applied to living skin or tissue to prevent infection.

Antiseptics cause no harm to living cells but do kill micro-organisms that could cause disease (pathogens)

54
Q

What is an organelle?

A

A small sub-structure which carries out a specific function within the cell

55
Q

What is meant by the term ‘field of view’?

A

This is the illuminated area that you can see when you look down the eye piece of a microscope.

56
Q

What is meant by the term ‘specialised cell’?

A

Cells that have structures, organelles and chemcials to carry out a particular function

57
Q

What is the advantage of a scientist observing a specimen using LOW power on a light microscope?

A

It allows the scientist to observe a greater AREA of the specimen

58
Q

What is the advantage of a scientist observing a specimen using HIGH power on a light microscope?

A

It allows the scientist to observe greater DETAIL in the specimen

59
Q

What is the difference between chlorophyll and chloroplast?

A

Chlorophyll is a molecule which absorbs light energy that is then used to produce glucose

Chloroplasts are small sub-cellular structures found in plant cells that carry out photosynthesis

Chloroplasts contain chlorophyll

60
Q

What is the function of the arm on a light microscope?

A

To enable the light microscope to be carried safely

61
Q

What is the function of the mirror on a light microscope?

A

To reflect the light beam up through the specimen and up through the eye piece

62
Q

What is the function of the stage clips on a light microscope?

A

To hold the microscope slide in a fixed position on the stage

63
Q

What is the function of the stage on a light microscope?

A

To support the slide

64
Q

What is the function/role of the mitochondria?

A

Site where AEROBIC respiration takes place to produce ATP

65
Q

What is the function/role of the cell membrane?

A

Controls what molecules enter and leave the cell contains the cytoplasm and cell organelles

66
Q

What is the function/role of the cell wall?

A

Supports the cell and strengthens the cell

67
Q

What is the function/role of the chloroplasts?

A

Chloroplasts are the site of photosynthesis

Where the plant cell makes glucose which is then converted to starch for storage

68
Q

What is the function/role of the cytoplasm?

A

Site of chemical reactions in the cell It contains enzymes and other cell organelles

69
Q

What is the function/role of the nucleus?

A

Contains the genetic information (DNA) of the cell

Controls the activities of the cell

70
Q

What is the function/role of the permanent vacuole?

A

Contains the cell sap

Cell sap is made of water with dissolved sugars and salts

71
Q

What is the function/role of the ribosomes?

A

Site where proteins are made within the cell

72
Q

What is the purpose of cell division in mature animals?

A

To repair tissues and organs

To replace damaged cells in tissues and organs

73
Q

What is the source of radiation in a light microscope?

A

Light rays

74
Q

What is the source of radiation in an electron microscope?

A

A beam of electrons

75
Q

What is the usual unit of size Biologists use to measure internal cell structures (organelles)?

A

Nanometre

76
Q

What is the usual unit of size that biologists use to measure cells?

A

Micrometre

77
Q

What structures and organelles do animal and plant cells have in common?

A

cell membrane

cytoplasm

genetic material (DNA) enclosed in a nucleus

ribosomes

78
Q

Which structures are not found in animal cells but are found in plant cells?

A

Cellulose cell wall

Chloroplasts

Large central permanent vacuole

79
Q

Which type of microscope has a greater resolving power (resolution) and higher magnification?

A

Electron microscope

80
Q

Why are disinfectants not used on living cells and tissues?

A

Disinfectants harm and kill the living cells.

81
Q

Why must agar plates ONLY be incubated at temperatures up to 25 degrees C

A

To prevent the growth of pathogenic (disease causing) bacteria

82
Q

Why must petri dishes be incubated upside down

A

So that any condensation that forms inside the dish falls into the lid and not onto the agar which would kill the bacteria

83
Q
A
84
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85
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86
Q
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87
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88
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89
Q

State the function of epithelial tissue in the stomach

A

To cover and line the surface of the stomach

90
Q

State the function of glandular tissue in the digestive system

A

To produce enzymes

These enzymes then break down substrates e.g. protease break down proteins into amino acids

To produce hydrochloric acid to kill pathogens and to create the optimum pH for enzymes in the stomach

91
Q

State the function of the musclar tissue in the stomach

A
  • To contract to move the walls of the stomach
  • So that the food is mixed with the enzymes
92
Q

What are the 6 key things to remember when drawing a biological diagram

A
  1. Use a sharp pencil
  2. Make sure your drawing occupies half the available space
  3. Draw smooth continuous lines
  4. Do not shade
  5. Add label lines and labels (i.e. name each part)
  6. Add annotations (i.e. describe each part e.g. smooth surface, stained blue)