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Biology Unit 1 > 1.2 cell structure and organisation > Flashcards

1.2 cell structure and organisation Flashcards

1
Q

What is the cell theory?

A

States that all organisms are composed of cells. Cells are the basic unit of life

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2
Q

What are unicellular organisms

A

Amoeba and bacteria

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3
Q

What are multicellular organisms?

A

Plants and animals

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4
Q

How are new cells made

A

Arise from pre existing cells

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5
Q

How are specialised cells formed?

A

Specialised cells arise from undifferentiated stem cells.

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6
Q

What did Antonie van Leeuwenhoek do?

A

Learned to grind lenses and assemble them into simple microscopes

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7
Q

What did Robert Hooke do?

A

Used a simple microscope to observe and draw cork cells.

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8
Q

What did Matthais Jacob Shleiden do?

A

Recognised that plants are composed of cells.

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9
Q

What did Theodor Schwann do?

A

Realised that animals were also composed of cells.

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10
Q

What did Rudolf Virchow do?

A

Proposed that all living cells arise from pre-existing cells.

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11
Q

Examples of Eukaryotic cells?

A

Animal and plant cells.

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12
Q

What do Eukaryotic cells have?

A

A nucleus and membrane bound organelles.

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13
Q

What makes a Eukaryotic cell different?

A

Each part has a different function.

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14
Q

What’s the difference between rough endoplasmic reticulum and smooth endoplasmic reticulum?

A

Rough endoplasmic reticulum have ribosomes attached to them

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15
Q

What is the nucleus?

A

A membrane-bound organelle found in eukaryotic cells. The largest organelle.

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16
Q

Diameter of a nucleus?

A

10-20 micrometres (μm)

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17
Q

What does the nucleus contain?

A

The nucleic acids DNA and RNA

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18
Q

What does DNA do?

A

Controls protein synthesis.
DNA is replicated in the nucleus.
DNS provides a template for the production of mRNA during transcription.

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19
Q

What is the nucleus surrounded by and what does it do?

A

Surrounded by a double membrane with nuclear pores. The pores allow the transport of large molecules out the nucleus

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20
Q

The nucleoplasm is inside the nucleus. What does it contain?

A

Contains chromatin, which is made up of coils of DNA bound to protein

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21
Q

What happens to chromatin during cell division?

A

Chromatic condenses to form chromosones.

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22
Q

What is the small spherical body in the nucleus?

A

The nucleolus

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23
Q

What does the nucleolus contain?

A

Pure DNA where RNA and ribosomes are produced.

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24
Q

What is the rough endoplasmic reticulum?

A

Network of fluid filled, flattened, membrane bound sacks which are connected to the nuclear membrane

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25
Q

What are ribosomes essential for?

A

Essential for protein synthesis (building proteins)

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26
Q

What’s the function of the rough endoplasmic reticulum

A

To package, modify, store and transport proteins to the Golgi body in transport vesicles

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27
Q

How is the Golgi body formed?

A

Transport vesicles are formed and merge to form the Golgi body

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28
Q

How are transport vesicles formed?

A

The ends of the rough endoplasmic reticulum are pinched off

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29
Q

What is transcription?

A

The genetic code in DNA is transcribed (copied) into mRNA molecules

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30
Q

What is translation?

A

The code carried by the mRNA is then translated by the ribosomes into a polypeptide (sequence of amino acids).

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31
Q

What are the two parts of the ribosome

A

Large subunit (at top) and small subunit (small subunit)

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32
Q

What two chemical components make up a ribosome?

A

Protein, rRNA

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33
Q

Where in the cell are ribosomes synthesised?

A

Nucleolus

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34
Q

Where are ribosomes located in eukaryotic cells?

A

On the outer surface of the rough endoplasmic reticulum

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35
Q

What does a smooth endoplasmic reticulum do?

A

Synthesizes, packages and transports fatty molecules called steroid and lipids.

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36
Q

How are functional proteins formed?

A

Polypeptides are further modified. E.g. Carbohydrate chains are added to form glycoproteins, digestive enzymes, and lysosomes.

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37
Q

What does the golgi body do?

A

Stores, packages and transports modified proteins

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38
Q

How are modified proteins transported?

A

Packaged into secretory vesicles, pinched off Golgi body, and transported to the cell membrane.

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39
Q

What is exocytosis?

A

Secretory vesicles fuse with the cell membrane and the modified/functional proteins are secreted from the cell.
An active process that uses ATP

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40
Q

What are lysosomes?

A

vesicles containing strong digestive enzymes.

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41
Q

How are lysosomes formed?

A

When portions of the Golgi body are pinched off

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42
Q

What do lysosomes do?

A

Fuse with organelles which are worn out/not functioning. Digestive enzymes released into the organelle and it is destoryed.

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43
Q

What does a lysosome do when a whole cell needs to be destroyed?

A

Lyses/bursts releases the digestive enzymes into the cytoplasm

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44
Q

How do phagocytes use lysosomes?

A

Use lysosomes to digest bacteria they’ve engulfed by phagocytosis.
Phagocyte forms a vacuole around the bacterial cell and the lysosome discharges its contents into the food vacuole and digests the bacteria

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45
Q

What does the mitochondria do?

A

Produces ATP by aerobic respiration

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46
Q

Length of the mitochondria?

A

1-10 micrometres (μm)

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47
Q

What do mitochondria have?

A

Double membrane separated by a narrow fluid-filled inter-membrane space

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48
Q

What are the folds in the inner membrane?

A

Extensions called cristae

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49
Q

What does cristae do?

A

Increase surface area of the inner membrane for more ATP production

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50
Q

What is the mitochondria filled of?

A

Organic matrix, containing protein, lipids and other chemical compounds

51
Q

What does DNA in the matrix do?

A

Allows mitochondria to control the production of their own proteins and replicate new organelles.

52
Q

Why do mitochondria sometimes appear sausage shaped/round in an electron micrograph?

A

Lying in different planes, or could be different ages/stages of development.

53
Q

Where are mitochondria most abundant in?

A

Cells with a high energy demand/high metabolism. e.g liver and muscle cells.

54
Q

What is a cytoskeleton?

A

A network of 3D protein microfilaments and microtubules

55
Q

What does a cytoskeleton do?

A

Anchors and facilitates movement of organelles within the cell

56
Q

Where are centrioles found?

A

All animal cells and most protoctists, but not in cells of higher plants.
Located just outside the nucleus in the centrosome in the cytoplasm

57
Q

How are centrioles formed?

A

From two circles of microtubules which make two hollow cylinders positioned at right angles to each other.

58
Q

What happens to centrioles during cell division?

A

Divide and move to the opposite poles of the cell where they synthesize the microtubules of the spindle

59
Q

Flagella

A

100 μm. Used to move cells or organelles

60
Q

Cilia

A

5-10μm long and move substances such as mucus

61
Q

Are plant cells eukaryotic or prokaryotic?

A

eukaryotic

62
Q

What do the cell walls do?

A

Strengthen and support plant tissues

63
Q

What are cell walls composed of?

A

Mainly composed of the structural polysaccharide cellulose

64
Q

Why does cellulose have a high tensile strength?

A

Prevents cellysis and maintains cell turgor/strength

65
Q

What is high tensile strength?

A

High maximum strength that a material can withstand while being stretched or pulled without breaking or bursting the cell

66
Q

What does plasmodesmata do?

A

Allows transport of substances between cells via the cytoplasm.

67
Q

What are plasmodesmata?

A

Cytoplasm filled canals which cells are connected by and which cross the cell wall

68
Q

What do plasmodesmata cross through?

A

Cellulose cell walls

69
Q

Why do plasmodesmata cross cellulose cell walls

A

To allow the transport of substances from cell to cell via the cytoplasm (symplastic pathway)

70
Q

What are vacuoles?

A

sacks full of cell sap with their own membranes

71
Q

What is the vacuole’s membrane called

A

Tonoplast

72
Q

What do vacuoles do?

A

The vacuole is the storage site for chemicals like glucose.
Helps support the cell and plant tissues

73
Q

How do vacuoles help support the cell and plant tissues

A

Fills with water by osmosis until the cell is turgid

74
Q

What do chloroplasts do?

A

Carry out photosynthesis

75
Q

Structure of chloroplasts

A

Each chloroplast surrounded by a double membrane. Fluid filled stroma that contains some of the products of photosynthesis.

76
Q

What does the stroma contain

A

Ribosomes, lipids, circular DNA and other structures like large starch grains

77
Q

What does DNA do in the chloroplast?

A

Allows replication of the chloroplast

78
Q

What are thylakoids

A

flattened sacks within the stroma.

79
Q

How is grana formed

A

By stacking thylakoids

80
Q

What is a single stack of thylakoids?

A

A granum.
Each granum consists of 2-200 of these closed, parallel, flattened sacks.

81
Q

What do the thylakoid membranes contain

A

Photosynthetic pigments like chlorophyll

82
Q

What does chlorophyll do?

A

Absorbs light energy

83
Q

What do folded membranes provide?

A

A large surface area for the absorption of more light energy

84
Q

What are prokaryotic cells

A

Cells which do not have membrane bound organelles

85
Q

What organelles do prokaryotic cells not have

A

No nucleus, rough endoplasmic reticulum, golgi apparatus, mitochondria, or chloroplastd

86
Q

What does the flagella do

A

Helps a prokaryotic cell move/swim

87
Q

Function of mesosome

A

Site of aerobic respiration

88
Q

What does pili do in prokaryotic cell

A

Helps cell stick to substances

89
Q

What does capsule do in prokaryotic cells?

A

Makes them less vulnerable to antibiotics

90
Q

Compare prokaryotic and eukaryotic cells

A

P are smaller (1-10um), E are larger (10-100um).
P have no membrane bound organelles, E have membrane bound organelles (mitochondria and nucleus).
P have circular DNA, E have linear DNA.
P cell wall made of peptidoglycan, E cell wall made of cellulose

91
Q

Viruses don’t have..

A

Cell membrane, cytoplasm, organelles, or chromosomes

92
Q

How do viruses reproduce

A

Invade a host cell

93
Q

What are viruses composed of

A

A protein coat/capsid, which surrounds DNA, RNA or a few genes.

94
Q

What does a virus exist as outside a living cell?

A

Exists as an inert viron

95
Q

How are viruses viewed

A

Electron microscope since they’re so small

96
Q

How does a virus invade a host cell?

A

Hijacks the cell’s metabolism and organelles to achieve protein synthesis and nucleic acid replication

97
Q

Viruses are

A

Pathogenic

98
Q

What does pathogenic mean

A

Cause a variety of infectious diseases in humans animals and plants

99
Q

Describe molecules to systems

A

Atoms arranged into molecules,
Molecules form cells,
Similar cells work together to form tissues.
Tissues perform specific functions.
Different tissues come together to form organs.
Different organs work together in systems

100
Q

What are tissues

A

Groups of similar specialised cells working together to perform a particular function

101
Q

What are organs

A

Formed from two or more tissues and have a definite form and function

102
Q

What is a system

A

Two or more organs working together to perform a specific function

103
Q

What is an organism

A

Several systems performing numerous roles

104
Q

What is histology?

A

The study of tissues

105
Q

What is epithelium

A

A lining tissue.

106
Q

Where do cells sit in epithelium?

A

Cells sit on a basement membrane and have a free surface on the other side

107
Q

Cuboidal epithelium information

A

Lines the kidney tubules and ducts of salivary glands.
Cube shaped

108
Q

Ciliated epithelium information

A

Composed of cells with Cilia.
Columnar shape

109
Q

What does cilia do

A

Transport substances like mucus in the bronchi. Move and sweep substances along

110
Q

Squamous epithelium information

A

Consists of flattened cells on a basement membrane.
Form the calls of the alveoli and line the Bowman’s capsule of the nephron in the kidney

111
Q

Skeletal muscle tissue characteristics

A
  • attaches and moves skeleton.
  • long bands of cells or fibres which interweave.
  • powerful contraction
  • fatigues and tires easily
  • voluntary
  • striped pattern of fibres. Striped/striated
112
Q

Smooth or unstriated muscle tissue characteristics

A
  • spindle shaped cells.
  • contract rhythmically.
  • less powerful than striated.
  • appear smooth : no stripes.
    -found in the skin and digestive and respiratory systems.
  • involuntary
  • responsible for peristalsis
113
Q

Heart muscle or cardiac muscle tissue characteristics

A
  • highly specualised
  • between striated and smooth.
  • contract rhythmically
  • never fatigues or tires
  • myogenic: every cell beats rhythmically and continuously
114
Q

What do connective tissues do?

A

Bind or separate tissues and organs

115
Q

Areolar tissue characteristics

A

Found under the skin.
Connects organs and tissues together.

116
Q

Collagen tissue characteristics

A

Forms tendons which connects muscles to bones

117
Q

Elastic tissues characteristics

A

Ligaments which connect bones

118
Q

Adipose tissue characteristics

A

Composed of fatty cells and is found just under the skin and around organs.
Functions as energy store, thermal insulator, and protects delicate organs. Provides buoyancy.

119
Q

How is total magnification of image calcated

A

objective lens magnification X eyepiece lens magnification

120
Q

Calibrating microscope meaning

A

Measure the actual size of structures on the slide

121
Q

Calculating the true size of a structure from magnified image

A
  1. Measure A-B in mm
  2. Divide by magnification
  3. Multiply by 1000 to convert mm to um (1mm=1000um)
122
Q

Calculating the surface area of a cylindrical organelle

A

Surface area = 2 pi radius (length+radius)

123
Q

Why are mitochondria cylindrical

A

Gives a larger surface area to volume ratio.
Shorter diffusion pathway so more oxygen can diffuse in and more carbon dioxide can diffuse out quickly. Aerobic respiration is more efficient so more ATP will be produced.

124
Q

Calculating surface area of sphere

A

4 pi radius2

(2=squared)

Biology Unit 1 (5 decks)

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