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Science Biology > B1 > Flashcards

B1 Flashcards

(47 cards)

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1
Q

What can a light microscope magnify up to?

A

-About X2000

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2
Q

What can an electron microscope magnify up to?

A

-About X2000000

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3
Q

What resolving power does a light microscope have?

A

-About 200nm

nm= nanometre

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4
Q

What resolving power does an electron microscope have?

A

-About 0.2nm

nm= nanometre

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5
Q

calculating the size of an object equation:

A

magnification = size of image/ size of real object
or
size of real object = size of image/ magnification

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6
Q

what can an electron microscope be used for?

A

-viewing thin specimens (tissue sections, molecules)

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7
Q

what can a light microscope be used for?

A

-viewing living cells (onion cells etc.)

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8
Q

what are the cells features in an animal cell and what are their functions?

A

nucleus: controls the cell, contains genes (chromosomes)
cytoplasm: liquid gel where most chemical reactions occur
cell membrane: controls what enters and exits cell
mitochondria: where aerobic respiration takes place
ribosomes: makes proteins for cell and is where protein synthesis takes place

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9
Q

what are the extra cells features in a plant cell and what are their functions?

A

cellulose, cell wall: strengthens the cells and gives it support

vacuole: filled with cell sap. keeps cell rigid to support plant
chloroplasts: contain chlorophyll which absorb light for photosynthesis

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10
Q

what are the main structure you would expect to find in a human cell?

A
  • nucleus
  • cytoplasm
  • cell membrane
  • mitochondria
  • ribosomes
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11
Q

what extra features are found in plant cell but not animal cells?

A
  • vacuole
  • cell wall
  • chloroplasts
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12
Q

why are the nucleus and mitochondria so important?

A
  • the mitochondria is where aerobic respiration takes place

- the nucleus controls the cell

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13
Q

What do all eukaryotic cells have?

A
  • cell membrane
  • cytoplasm
  • genetic material in a nucleus
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14
Q

what do prokaryotes (bacterial cells) consist of?

A
  • cytoplasm
  • cell membrane
  • cell wall
  • genetic material not in a nucleus
  • plasmids: extra small rings of dna
  • slime capsule: extra protection
  • flagella: to move
  • ribosomes
  • pili: hair-like structure allow bacterial cells to stick to other surfaces
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15
Q

what can happen to an animal organism as it develops?

A

-cells can differentiate to form idfferent types of cells such as nerve cells, muscle cells, sperm cells etc.

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16
Q

how are nerve cells adapted?

A
  • lots of dendrites to make connections to other nerve cells
  • axon carries nerve impulse for one place to another
  • synapse (nerve ending) adapted to pass impulses to another cell
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17
Q

how are muscle cells adapted?

A
  • contain special proteins that slide over each other making fibres contract
  • contain mitochondria to transfer energy needed for chemical reactions that occur as cells contract
  • store glycogen that can be broken down and used for aerobic respiration
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18
Q

how are sperm cells adapted?

A
  • long tails whips to help move sperm
  • middle section full of mitochondria which transfer energy needed for tail to work
  • acrosome stores digestive enzymes for breaking down outer layers of the egg
  • large nucleus contains genetic info to be passed on
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19
Q

how are root hair cells adapted?

Study These Flashcards
A
  • increased surgace area for water to move into the cell
  • vacuole speeds up movement of water by osmosis
  • mitochondria transfer energy for active transport of mineral ions into root hair cells
20
Q

how are phloem cells adapted?

Study These Flashcards
A

-cell walls break down to form sieve plates which allow water carrying dissolved food to move up + down tubes

21
Q

how are xylem cells adapted?

Study These Flashcards
A
  • cells die + form long hollow tubes to carry water + mineral ions from one end of plant to the other
  • spirals and lignin help them withstand pressure of water moving up plant
22
Q

how are photosynthetic cells adapted?

Study These Flashcards
A
  • chloroplasts contain chlorophyll that trap light for photosynthesis
  • continuous layers in leaves and outer layers of stem so they absorb most light
  • vacuole helps keep leaf spread out to get most sunlight
23
Q

what is the function of root hair cells?

Study These Flashcards
A

-to absorb minerals and water from soil

24
Q

what is the function of photosynthetic cells?

Study These Flashcards
A

-plants can make their own food

25
what is the function of xylem cells?
- to support the plant | - to carry water and mineral ions from roots to the highest leaves and shoots
26
what is the function of phloem cells?
-carries food made by photosynthesis around the plant
27
what is diffusion?
the spreading out of particles of any substance, in solution or gas, resulting in a net movement from a high concentration to an area of low concentration, down a concentration gradient
28
why does diffusion take place faster when there is an increase in temperature?
-the particles in a gas or solution move around more quickly (speed up) so diffusion takes place more rapidly
29
what affects the rate of diffusion?
- the difference in concentrations - the temperature - the available surface area
30
what is a concentration gradient?
the difference between two areas of concentration
31
define net movement:
net movement = particles moving in - particles moving out
32
what is osmosis?
- a special type of diffusion - the movement of water from a dilute to a more concentrated solution through a partially permeable membranethat allows water to pass through
33
what is the difference between osmosis and diffusion?
- osmosis occurs across a partially permiable membrane while diffusion does not - osmosis in organisms also only refers to the diffusion of water molecules
34
what is a partially permeable membrane?
-membranes that only let some types of particles through
35
in osmosis what is a dilute solution of sugar?
contains a high concentration of water and has a low concentration of sugar
36
in osmosis what is a concentrated solution of sugar?
-contains a relatively low concentration of water and a high concentration of sugar
37
what is an isotonic solution?
-when the concentration of solutes in the solution outside the cell is the same as the internal concentration
38
what is a hypotonic solution?
-when the concentration of solutes in the solution outside the cell is lower than the internal concentration
39
what is a hypertonic solution?
-when the concentration of solutes in the solution outside the cell is higher than the internal concentration
40
what is a solute?
- the minor component in a solution | - dissolved in the solvent
41
what is a solvent?
-the liquid in which a solute is dissolved to form a solution
42
what do differences in the concentration of solutions inside and outside a cell do?
-cause water to move into or out of the cell by osmosis
43
how can osmosis cause big problems in animals?
- if solution outside the cell becomes much more dilute than the cell contents water will move in by osmosis + the cell will swell + may burst - if solution outside the cell becomes much more concentrated than the cell contents, water will move out of the cell by osmosis + the cytoplasm will become to concentrated + the cell will shrivel up + die
44
why is osmosis so important in plants cells?
- to maintain turger (hard and rigid) which keeps the leaves and stem of the plant firm - its the way the plants get water through its leaves and root hair cells
45
how does active transport work in a cell?
-active transport moves substances from a more dilute solution to a more concentrated solution (against a concentration gradient)
46
where does active transport get its energy for use from?
-active transport uses energy released from food in respiration to provide the energy required
47
why is active transport important?
- it allows plant root hairs to absorb mineral ions required for healthy growth from very dilute solutions in soil against a concentration gradient - it enables sugar molecules used for cell respiration to be absorbed from lower concentrations in the gut into the blood where concentration of sugar is higher

Science Biology (11 decks)

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