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Bio > Cells+transport Acrlss Membranes > Flashcards

Cells+transport Acrlss Membranes Flashcards

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1
Q

Detail shown in the diagram above would not be seen using an optical microscope

A

Light has a longer wavelength
So lower resolution

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2
Q

Name an organelle found in both chloroplast and a prokaryotic cell

A

70S ribosome

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3
Q

Explain the adaptation of many mitochondria and golgi vesicles

A

Many mitochondria release ATP for synthesis of protein/ AT

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4
Q

Name process by which prokaryotic cells divide

A

Binary fission

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5
Q

Give 2 structures found in all prokaryotic and eukaryotic cells

A

Cell surface membrane
Ribosome
Cytoplasm
Dna

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6
Q

Suggest one explanation for faster rate of plasmid replication in higher conc of amino acids

A

Amino acids used in protein synthesis
Amino acids used in respiration
More energy ATP

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7
Q

Function of chloroplast

A

• absorbs light
• performs photosynthesis
• produce carbohydrates/lipids/sugars/proteins

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8
Q

Same organelle can appear differently because

A

• idea that only a cross-section is seen
• idea that mitochondria are orientated differently

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9
Q

Explain how the inner membrane is adapted to its function in mitochondria

A

• Folded/has cristae
WHICH
• increase surface area
• for respiration/phosphorylation

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10
Q

function of capsule

A

• Protects immune system
• Aids bacteria sticking together

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11
Q

Function of plasmid

A

circular piece of DNA containing few genes for antibiotic drug resistance

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12
Q

Cell wall

A

Strengthens and protects the cell
Stops osmotic lysis

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13
Q

Flagellum

A

Allows movement
*would have loads of mitochondria to produce energy from ATP

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14
Q

Other than being smaller, give two ways in which prokaryotic DNA is different from eukaryotic DNA.

A

• Eukaryotic cells have DNA which is linear and associated with histones

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15
Q

Describe how you could use cell fractionation to isolate chloroplasts from leaf tissue

A

• Break open the cells in a blender/ homogenise cells in a blender and filter to remove cellular debris
• place in an ice cold, isotonic, buffered solution
• use differential centrifugation
• chloroplasts are in the second pellet

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16
Q

Explain why solution is isotonic, ice cold, buffered

A

• Prevents osmosis SO no osmotic lysis of organelles so cells are not damaged
• Ice cold reduce activity of digestive enzymes
• Buffered to prevent changes in PH as this could denature proteins

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17
Q

What can A light microscope only see

A

Nucleus and cell membrane

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18
Q

What is the largest organelle

A

Nucleus
* so in ultracentrifugation this would be first cause most dense

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19
Q

Rough Endoplasmic Reticulum (RER)

A

Synthesises and transports proteins throughout the cell
• has 80s ribosomes embedded
• folded into flattened sacs called cisternae

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20
Q

Smooth Endoplasmic Reticulum

A

• recombines glycerol and fatty acids to make triglycerides
• packages triglycerides into vesicles and transports them to the Golgi apparatus

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21
Q

Ribosomes function

A

Site of protein synthesis
• eukaryotic contain 80S eukaryotic 70S

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22
Q

Describe how lactose is formed and where in the cell it would be attached to a polypeptide

A

Glucose + galactose
Joined by condensation reaction
Joined by glycosidic bond
Added to polypeptide in Golgi apparatus

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23
Q

Why is the tissue homogenised?

A

To release cell contents (organelles)

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24
Q

Advantages and disadvantages of using a TEM to investigate cell structure

A

Advantages
•Small objects can be seem
TEM has high resolution
• electrob wavelength is shorter

LIMITATIONS
• cannot look at living cells
• Must be in a vacuum
• Must cut section
Complex staining method
May produce artefacts

25
Q

Differences between bacterial and animal cell

A

Flagellum, No nucleus DNA free in cytoplasm

26
Q

Contrast how an optical microscope and a transmission electron microscope work and contrast the limitations of their use when studying cells.

A
  1. TEM use electrons and optical use light;
  2. TEM allows a greater resolution;
  3. So with TEM smaller organelles can be seen and in greater detail
  4. TEM view only dead specimens and optical can view live specimens;
  5. TEM does not show colour and optical can;
  6. TEM requires thinner specimens;
  7. TEM requires a more complex and time consuming preparation;
  8. TEM focuses using magnets and optical us
27
Q

Phospholipids

A

Allows lipid soluble molecules thru simple diffusion prevents passage of polar molecules

28
Q

Channel proteins

A

Molecules move through facilitated diffusion
Specific 3•
So only transport molecules that are complementary to the binding site

29
Q

Carrier proteins

A

Transport of polar+large molecules
Facilitated diffusion or active transport

30
Q

Aquaporins

A

Channel proteins specific to water
Lots of aquaporins- permeable to water

31
Q

Two functions of membranes in cells are to

A

• Separate the internal cell environment from the external environment
•regulate movement

32
Q

Cell membranes are described as fluic mosaics because

A

• molecules in the membrane move sideways past each other

33
Q

Movement of substances across a cell membrane is affected by membrane structure. Describe how

A
  1. phospholipid bilayer allows movement of non-polar/ lipid-soluble substances
  2. Phospholipid bilayer prevents movement of polar/charges/lipid-insoluble substances
  3. Carrier proteins allow active transport
  4. Channel/ carrier proteins allow facilitated diffusion
  5. Shape/ charge channel/ carrier determines which substances move
  6. Number of channels/ carriers determines how much movement
  7. Membrane surface area determines how much diffusion/ movement
  8. Cholesterol affects fluidity/rigidity/ permeability
34
Q

Describe the structure of a phospholipid molecule and explain how phospholipids are arranged in a plasma membrane

A

Glycerol joined to 2 fatty acid tails and phosphate group joined to glycerol on opposite head (joined by condensation reactions with ester bonds)

Phospholipid had hydrophilic head and hydrophobic tails
• Which arrange to form a phospholipid bi-layer with hydrophilic heads facing outwards and hydrophobic tails facing inwards

35
Q

Explain why a cell may be described as a fluid-mosaic

A

• The position of the molecules within the membrane is fluid- they are able to move around within the membrane
• Membrane is made up of a variety of molecules arranged into a mosaic

36
Q

Describe how a substance can cross a cell surface membrane

A

• Simple/facilitated diffusion from an area of higher to lower concentration/down concentration gradient
• Small/non-polar/lipid-soluble molecules pass via phospholipid bilayer
• Water moves by osmosis from an area of higher water potential to lower water potential
• Active transport is movement from lower to higher concentration/against concentration gradient
• Active transport and facilitated diffusion involves proteins
• Active transport requires ATP

37
Q

Describe the roles of iron ions, sodium ions and phosphate ions in cells

A

Iron ions
1. Haemoglobin binds/associates with oxygen
OR
Haemoglobin transports/loads oxygen;
Sodium ions
2. Co-transport of glucose/amino acids (into cells);
3. (Because) sodium moved out by active transport/Na - K pump;
4. Creates a sodium concentration/diffusion gradient;
5. Affects osmosis/water potential;
Phosphate ions
6. Affects osmosis/water potential;
7. Joins nucleotides/in phosphodiester bond/in backbone of DNA/RNA/in nucleotides;
8. Used in/to produce ATP;
9. Phosphorylates other compounds (usually) making them more reactive;
10. Hydrophilic/water soluble part of phospholipid bilayer/membrane;

38
Q

Suggest how glycogen acts as a source of energy (2)

A
  • hydrolysed to glucose
  • glucose used in respiration
39
Q

Suggest and explain two ways the cell-surface membranes of the cells lining the uterus may be adapted to allow rapid transport of nutrients.

A
  1. Membrane folded so increased/large surface area;
    OR
    Membrane has increased/large surface area for (fast) diffusion/facilitated diffusion/active transport/co-transport;
  2. Large number of protein channels/carriers (in membrane) for facilitated diffusion;
  3. Large number of protein carriers (in membrane) for active transport;
  4. Large number of protein (channels/carriers in membrane) for co-transport;
40
Q

Loss of ions from cell likely to lead to

A

Death

41
Q

Factors affecting rate of diffusion

A

Temp
Sa
Conc gradient
Diffusion distance

42
Q

What are ribosome made from

A

rRna and ribosomal proteins

43
Q

The structure of a cholera bacterium is different from the structure of an epithelial cell from the small intestine. Describe how the structure of a cholera bacterium is different.

A

1 Cholera bacterium is prokaryote;
2 Does not have a nucleus/nuclear envelope/ has DNA free in cytoplasm/has loop of DNA;
3 and 4 Any two from
No membrane-bound organelles/no mitochondria / no golgi/
no endoplasmic reticulum/etc;
5 Small ribosomes only;
6 and 7 Any two from
Capsule/flagellum/plasmid / cell wall/etc;

44
Q

Graphs shoeing processes of movement

A

Without oxygen , facilitated diffusion or diffusion
With oxygen active transport as oxygen required for AT
As requires in respiration to produce ATP to provide energy

45
Q

If no diffusion gradient

A

No facilitated/simple diffusion

46
Q

Ensuring solutions contain no oxygen

A

Use boiled+cooled water

47
Q

Explain why plants grown in soil with very little water grow slowly

A

Stomata close
Less co2 uptake for photosynthesis

48
Q

Monomer

A

Smaller unit from which polymers are made from

49
Q

Give 2 similarities in movement of substances by diffusion and by osmosis

A

Movement down a gradient
Both passive processes

50
Q

What is algae cell wall made from

A

Cellulose

51
Q

Suggest why nucleus not visible in tem image

A

Nucleus not stained

52
Q

Types of eukaryotic cells

A

Algae
Animal
Plants
Fungi

53
Q

What can golgi body also be used for

A

Form lysosomes

54
Q

Where are centrioles found not found

A

PLANT CELLS

55
Q

Diff between animal+ plant cell

A

Animal has centrioles whereas plant doesnt
Plant has chloroplast+vacuole whereas animal does not
Carb store in chloroplast= starch whereas carb store in glycogen

56
Q

Energy storage molecule in chloroplast

A

Starch grain

57
Q

Why can’t viruses replicate independently

A

They have no organelles

58
Q

Higher magnification= lower resolution

A

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