Cells, Enzymes and Transport - TOPIC 1 Flashcards

1
Q

what sub cellular structures are in animal cells

A
nucleus
cytoplasm
cell membrane
mitochondria 
ribosomes
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2
Q

what is the function of the nucleus

A

contains genetic material that controls the activities of the cell

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3
Q

what is the function of the cytoplasm

A

it is where most chemical reactions take place

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4
Q

what is the function of the cell membrane

A

it holds the cell together and controls what goes in and out of the cell

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5
Q

what is the function of mitochondria

A

where most reactions for aerobic reactions take place and respiration transfers energy the cell needs to work

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6
Q

what is the function of ribosomes

A

involved in protein synthesis

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7
Q

what is the function of cell wall

A

it supports and strengthens the cell

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8
Q

what is the function of the vacuole

A

contains the cell sap and maintain the internal pressure to support the cell

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9
Q

what is the function of the chloroplasts

A

where photosynthesis occurs and contains chlorophyll which absorbs light needed for photosynthesis

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10
Q

what sub cellular structures are in plant cells

A
nucleus
cytoplasm
cell membrane
mitochondria 
ribosomes 
cell wall
vacuole 
chloroplasts
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11
Q

what sub cellular structures are in bacterial cells

A
cell membrane 
ribosomes
cytoplasm 
plasmid DNA
chromosomal DNA
flagellum 
cell wall
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12
Q

what are the adaptations of a sperm cell

A

it has a long tail to swim to the egg and a lot of mitochondria to provide the energy to swim to the egg

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13
Q

what does the acrosome in a sperm cell do

A

it stores the enzymes the sperm needs to digest its way through the membrane of the egg cell

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14
Q

adaptations of an egg cell

A

it contains nutrients in the cytoplasm to feed the embryo AND it’s membrane changes structure to stop anymore sperm getting in

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15
Q

what is a haploid nucleus

A

a nucleus that contains half the number of chromosomes - 23

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16
Q

adaptations of ciliated epithelial cells

A

they have cilia at the top which beat to move substances away such as mucus up the throat so it can be swallowed

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17
Q

why do we need microscopes

A

the allow us to see things we can’t see with the naked eye such as individual cells and their subcellular structures

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18
Q

positives of light microscopes

A

cheap

light

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19
Q

negatives of light microscopes

A

worse magnification and resolution

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20
Q

positives of electron microscopes

A

higher magnification and resolution so we can see organelles and cell structures in more detail and increase our understanding

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21
Q

negatives of electron microscopes

A

can’t be used to view living cells
expensive
take up too much space (around the size of a room)

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22
Q

how do you prepare a slide for a light microscope

A
  1. Add a drop of water to the middle of a slide
  2. Cut up an onion and peel of some epidermal tissue
  3. use tweezers to place tissue into the water
  4. add a drop of iodine solution
  5. place a cover slip over the specimen
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23
Q

how to set up and use a light microscope

A
  1. Clip down the slide onto the stage
  2. Select the lowest powered objective lens
  3. Use coarse adjustment knob to move stage to just below the objective lens
  4. look down they eyepiece
  5. use coarse adjustment knob to move stage down until image is roughly in focus
  6. adjust focus until clear with fine adjustment knob
  7. Increase magnification with higher objective lens
24
Q

total magnification =

A

eyepiece lens magnification x objective lens magnification

25
Q

magnification =

A

image size / actual size

26
Q

what is a catalyst

A

a substance which increases the speed of a reaction, without being changed or used up in the reaction

27
Q

what is an active site

A

a unique shaped place in an enzyme which has a specific sized substrate to start the reaction

28
Q

what are the 3 conditions enzymes need to work best

A

37 degrees celsius temperature
pH of 7 (mostly)
substrate concentration

29
Q

what happens to the rate of reaction as the temperature increases

A

At first, the rate increases but if it gets too hot, the bonds holding the enzyme together break and the enzyme gets denatured so the reaction will stop or slow down

30
Q

what happens to the rate of reaction as the substrate conc increases

A

the rate increases but only up until a point as after that the rate will remain constant

31
Q

how does pH affect the rate of reaction

A

if the pH is too high, the enzyme will denature and if it is too low the reaction will be slow

32
Q

how to investigate how pH affects amylase activity

A
  1. Put a drop of iodine solution into every well of a spotting tile
  2. Place a bunsen burner on a heat proof mat and a tripod and gauze over that.
  3. Place a beaker of water on top of the bunsen burner and heat until it reaches the optimum temp using a thermometer
  4. Use a syringe to add a bit of amylase solution and a buffer solution with pH 5 to a boiling tube and wait 5 minutes
  5. use a different syringe to add a bit of starch solution to the boiling tube and mix immediately and start a stop clock
  6. record how long it takes the amylase to break down all the starch by placing a drop of the solution from boiling tube into a different well every 30 secs
  7. When idodine solution remains brown/orange, starch is no longer present
  8. repeat with buffer solutions of different pH values
33
Q

rate =

A

1000 / time

34
Q

importance of enzymes in breakdown reactions

A

carbs, proteins and lipids need to be broken down into smaller components to be used for growth and other life processes

35
Q

what do carbohydrases convert carbohydrates into

A

simple sugars

36
Q

what does protease convert proteins into

A

amino acids

37
Q

what does lipase convert lipids into

A

glycerol and fatty acids

38
Q

rate =

A

change / time

39
Q

what is the test for starch

A

add a drop of iodine solution to each sample and wait for colour change, if it goes black starch is present and if it goes yellow it is negative

40
Q

what is the test for protein

A

Biuret test :

put two spatulas of food in test tube, add 1cm of water and stir. Add potassium hydroxide and copper oxide then stir

41
Q

what is the positive and negative results in the test for protein

A

positive - purple

negative - blue

42
Q

what is the test for reducing sugars

A

Put two spatulas food in test tube and add water then mix. Put Benedict’s in and heat tubes in a water bath (75 degrees)

43
Q

what is the positive and negative results in the test for reducing sugars

A

positive - green/red

negative - blue

44
Q

what is the test for lipids

A

put two spatulas of food in the test tube. Add ethanol and shake. Pour liquid from the top of the mixture into tube filled half with water.

45
Q

what is the positive and negative results in the test for lipids

A

positive - milky white emulsion

negative - clear

46
Q

how to do calorimetry

A
  1. Weigh a little food and skewer it on a mounted needle
  2. add set volume of water to a boiling tube with a clamp
  3. measure temp of water
  4. set fire to food with bunsen burner
  5. hold food under tube until fire goes out
  6. relight food and hold it under tube and repeat until food wont catch fire again
  7. measure temp of water again and record temp change
47
Q

what is calorimeter used for

A

to find out the amount of energy in food

48
Q

energy in food =

A

mass of water x temp change of water x 4.2

49
Q

energy per gram of food =

A

energy in food / mass of food

50
Q

what is diffusion

A

the net movement of particles from an area of higher conc to an area of lower conc down a concentration gradient, as a result of their random movement until equilibrium is reached

51
Q

what is a partially permeable membrane

A

cell membranes which let some molecules through (small) but not others

52
Q

what is osmosis

A

the net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration

53
Q

what is active transport

A

movement of particles from an area of lower concentration to an area of higher concentration using energy transferred during respiration

54
Q

what is an experiment to show osmosis in potatoes

A
  1. cut potato in small discs of equal size
  2. blot potato gently with tissue paper
  3. measure initial mass of each disk
  4. place disks in sucrose solutions of different conc
  5. blot with tissue paper again and record new mass
55
Q

percentage change in mass =

A

(final mass - initial mass) / initial mass x 100