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Cells+transport Acrlss Membranes Flashcards

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
Differences between bacterial and animal cell
Flagellum, No nucleus DNA free in cytoplasm
26
Contrast how an optical microscope and a transmission electron microscope work and contrast the limitations of their use when studying cells.
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
Phospholipids
Allows lipid soluble molecules thru simple diffusion prevents passage of polar molecules
28
Channel proteins
Molecules move through facilitated diffusion Specific 3• So only transport molecules that are complementary to the binding site
29
Carrier proteins
Transport of polar+large molecules Facilitated diffusion or active transport
30
Aquaporins
Channel proteins specific to water Lots of aquaporins- permeable to water
31
Two functions of membranes in cells are to
• Separate the internal cell environment from the external environment •regulate movement
32
Cell membranes are described as fluic mosaics because
• molecules in the membrane move sideways past each other
33
Movement of substances across a cell membrane is affected by membrane structure. Describe how
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
Describe the structure of a phospholipid molecule and explain how phospholipids are arranged in a plasma membrane
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
Explain why a cell may be described as a fluid-mosaic
• 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
Describe how a substance can cross a cell surface membrane
• 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
Describe the roles of iron ions, sodium ions and phosphate ions in cells
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
Suggest how glycogen acts as a source of energy (2)
- hydrolysed to glucose - glucose used in respiration
39
Suggest and explain two ways the cell-surface membranes of the cells lining the uterus may be adapted to allow rapid transport of nutrients.
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
Loss of ions from cell likely to lead to
Death
41
Factors affecting rate of diffusion
Temp Sa Conc gradient Diffusion distance
42
What are ribosome made from
rRna and ribosomal proteins
43
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.
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
Graphs shoeing processes of movement
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
If no diffusion gradient
No facilitated/simple diffusion
46
Ensuring solutions contain no oxygen
Use boiled+cooled water
47
Explain why plants grown in soil with very little water grow slowly
Stomata close Less co2 uptake for photosynthesis
48
Monomer
Smaller unit from which polymers are made from
49
Give 2 similarities in movement of substances by diffusion and by osmosis
Movement down a gradient Both passive processes
50
What is algae cell wall made from
Cellulose
51
Suggest why nucleus not visible in tem image
Nucleus not stained
52
Types of eukaryotic cells
Algae Animal Plants Fungi
53
What can golgi body also be used for
Form lysosomes
54
Where are centrioles found not found
PLANT CELLS
55
Diff between animal+ plant cell
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
Energy storage molecule in chloroplast
Starch grain
57
Why can’t viruses replicate independently
They have no organelles
58
Higher magnification= lower resolution

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