Biology 2a flashcards

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  • Created by: Evie
  • Created on: 20-04-13 13:14
What are the five main parts of animal cells and what are their functions?
Nucleus (DNA that controls activities), Cytoplasm (gel-like substance containing enzymes, where most reactions take place), Cell membrane (holds cell together, controls in/out), Ribosomes (where proteins are made), Mitochondria (respiration happens)
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What 3 features to plant cells have which animal cells do not? What are their functions?
Cell wall (made of cellulose+supports cell), Vacuole (contains cell sap, a weak solution of sugar/salts), Chloroplasts (where photosynthesis occurs)
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What features to yeast cells have? What about bacteria?
Yeast - cell wall, cell membrane, cytoplasm&nucleus. Bacteria have the same features but no nucleus, their DNA floats around
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Define diffusion. How do cell membranes use it?
The spreading out of particles from an area of low concentration to an area of high concentration. Cell membranes only let small molecules through (oxygen, glucose, water & amino acids)
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How are palisade leaf cells specialised?
More chloroplasts are at the top of the cells, nearer light. Tall shape=big surface area. Thin shape= pack lots of them at the top. Grouped together at top, where most photosynthesis happens.
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How are guard cells specialised?
Open and close the stomata(pores). When the plant has lots of water - turgid/plump so the stomata open to exchange gases for PS. When short of water -flaccid so stomata close, stopping water vapour escaping. Light sensitive/close at night.
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How are red blood cells specialised?
Concave shape=big surface area for absorbing 02 and helps pass through capillaries to reach body cells. Packed with haemoglobin, the pigment that absorbs 02. No nucleus so more room for haemoglobin.
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How are sperm and egg cells specialised?
Sperm - long tail, streamlined head to swim, lots of mitochondria for energy, enzymes in head to digest through egg cell membrane. Egg - huge food reserves, large so sperm can reach it, membrane change to stop more than 1 sperm.
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What is a tissue? Examples?
A group of similar cells that work together to carry out a particular function. Muscular tissue contracts/shortens to move, glandular tissue makes/secretes chemicals like enzymes & hormones, epithelial tissue which covers the inside of the gut etc
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What tissues make up leaves?
Mesophyll tissue- where PS occurs. Xylem/phloem - transport things like water, mineral ions and sucrose around the plant. Epidermal tissue - covers whole plant
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What is the function of chloroplasts/chlorophyll?
chlorophyll absorbs sunlight and uses its energy to convert CO2 from the air and water from the soil, into glucose.
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What is a limiting factor? Examples?
something that stops PS going any faster, not enough light or % level of C02.
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What experiment could you carry out to work out the ideal conditions for PS?
Use a water plant like Canadian Pondweed. You can measure the amount of oxygen produced in a given time by count the bubbles being given off or collecting oxygen in a gas syringe.
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What is the optimum temperature for most enzymes? When do they denature?
37 degrees, 45 degrees
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What are some pros to using a greenhouse?
Traps suns heat so temperature is less likely to be a limiting factor. You can use heaters if its cold. If its too hot you can use ventilation or shades. You can increase CO2 levels by burning a paraffin lamp. Less risk of pests/diseases
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5 ways plants use glucose?
Respiration, making cell walls, making proteins, stored in seeds & stored as starch
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How do plants use glucose for respiration?
It releases energy which enables them to convert the rest of the glucose into other substances which they can use to grow etc.
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How do plants use glucose for - making cell walls/proteins?
Glucose is converted to cellulose for making strong cell walls. Glucose is combined with nitrate ions from the soil to make amino acids.
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How do plants store glucose in seeds/starch?
Turned into lipids for storing in seeds. Starch - stored in roots,stems and leaves so its ready for use when PS isn't happening. Starch is insoluble so unlike glucose it wouldn't draw in lots of water and swell.
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Other cards in this set

Card 2

Front

What 3 features to plant cells have which animal cells do not? What are their functions?

Back

Cell wall (made of cellulose+supports cell), Vacuole (contains cell sap, a weak solution of sugar/salts), Chloroplasts (where photosynthesis occurs)

Card 3

Front

What features to yeast cells have? What about bacteria?

Back

Preview of the front of card 3

Card 4

Front

Define diffusion. How do cell membranes use it?

Back

Preview of the front of card 4

Card 5

Front

How are palisade leaf cells specialised?

Back

Preview of the front of card 5
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