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Biology Paper 1 > CB1 - Key concepts in Biology > Flashcards

CB1 - Key concepts in Biology Flashcards

1
Q

What is the function of the Nucleus?

A

Contains genetic material (DNA). It is arranged into chromosomes.

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2
Q

What is the function of the Cell membrane?

A

Holds the cell together and control what goes in and out.

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3
Q

What is the function of the Mitochondria?

A

Where the most of the reactions for respiration take place. Respiration transfers energy for the cell.

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4
Q

What is the function of the Ribosomes?

A

Involved in translation of genetic material in protein synthesis.

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5
Q

What is the function of the Cell wall?

A

Made of cellulose. Supports the cell and strengthens it.

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6
Q

What is the function of the Chloroplast?

A

This is where photosynthesis occurs. It contains a green substance called chlorophyll.

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7
Q

What is the function of the Vacuole?

A

Contains cell sap (A weak solution of sugars and salts). Maintains internal pressure to support cell.

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8
Q

What is the function of the Chromosomal DNA?

A

Controls cells activities and replication. It floats free in the cytoplasm.

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9
Q

What is the function of the Plasmid DNA?

A

Small loops of extra DNA that aren’t part of the chromosomes. Contains genes for things like drug resistance.

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10
Q

What is the function of the flagella?

A

A long hair-like structure that rotates to make bacterium move.

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11
Q

What is the function of the Acrosome?

A

At the front of the sperm. Stores enzymes needed to digest through membrane of egg.

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12
Q

What is the function of the Haploid nucleus?

A

Contains genetic info for fertilisation.

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13
Q

What is the function of the Tail?

A

Helps sperm to swim in egg cell.

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14
Q

What is the function in the nutrients in the cytoplasm?

A

Feeds the embryo.

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15
Q

What changes in the cell membrane after fertilisation?

A

Changes structure so does not let any sperm in. Makes sure that offspring have right amount of DNA.

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16
Q

What is Ciliated epithelial cells?

A

Line the surface of organs. Function : Moves substance - the cilia move substance in one direction.

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17
Q

What is the difference between Light and Electron microscopes?

A

Light : Invented in 1950’s. Work by passing light through specimen. Let us see nuclei and chloroplast.
Electron : Invented in 1930’s. Use electron than light. Have higher magnification and resolution, so let us see smaller things like internal structure. Allowed us to have much greater understanding of how cells works.

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18
Q

When should Estimation should be used?

A

When there is no scale.

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19
Q

Millimetre (mm)

A

Standard form : 10-3
Millimetre to Micrometre : x1000

20
Q

Micrometre (µm)

A

Standard from : 10-6
Micrometre to Nanometre : x1000

21
Q

Nanometre (nm)

A

Standard form : 10-9
Nanometre to Picometre : x1000

22
Q

Picometre (pm)

A

Standard form : 10-12

23
Q

Practical : Investigate biological specimen under a microscope

A
  1. Make thin slice of specimen
  2. Take a clean slide and put one drop of water on (Secure specimen on slide)
  3. Use tweezers to put specimen on slide
  4. Add drop of stain if specimen it transparent.
  5. Put cover slip carefully on specimen and make sure there is no air bubbles.
  6. Clip the slide onto stage.
  7. Select lowest- powered objective lens
  8. Adjust the focus with fine adjustment knob until you get a clear image.
24
Q

How to calculate Total Magnification?

A

Total Magnification = Eyepiece lens mag x Objective lens mag

25
Q

How to calculate Magnification?

A

Magnification = Image size / Real Size

26
Q

How to draw Scientific drawing of specimen?

A
  1. Use a sharp pencil and draw outlines of main feature using clear, unbroken lines.
  2. Make sure drawing takes half of the space given to draw.
  3. Label the important features of your diagram and don’t cross over and include magnification and use a scale.
27
Q

Explain the mechanism of enzyme action?

A

For enzyme to work, substrate has to fit into active site. If it does not fit, the reaction wont be catalysed. It is called “Lock and Key mechanism”.

28
Q

What is the Active site?

A

Every enzyme has active site - Part where it joins on to substrate to catalyse.

29
Q

What is Enzyme Specificity?

A

Limitation of enzyme to catalyse one specific reaction with one specific substrate.

30
Q

Explain how enzymes can be denatured due to changes in shape of active site?

A

If enzyme exposed to high temp, the shape of active site may change.

31
Q

Explain the effect of temperature on enzyme activity?

A

Changing temp changes rate of enzyme reaction. A high temp increases rate till certain point, if increases from this point the binds will break holding the enzyme together. The enzyme is denatured. All have an optimum temp where they work the best.

32
Q

Explain the effect of substrate concentration on enzyme activity?

A

Affects rate of reaction - higher the substrate conc, faster the reaction. More likely that enzyme will meet up and react with substrate molecule.

33
Q

Explain the effect of pH on enzyme activity?

A

pH also effects enzyme. If it’s too high or low, pH interferes and holds the binds. Changes shape of active site and denature. All enzyme have optimum pH, mostly pH 7.

34
Q

Practical : Investigate effect of pH on enzyme activity

A
  1. Put a drop of iodine in every spotting tile
  2. Set a Bunsen burner. Put a beaker on to the tripod and heat water until 35 Celsius (try to keep temp constant).
  3. Use syringe to add 3cm^3 of amylase solution and 1cm^3 of buffer solution with pH 5 to boiling tube - put tube in beaker.
  4. Use different syringe to add 3cm^3 of starch solution to tube.
  5. Mix contents and start a stop clock.
  6. Use continuous sampling to record how long it takes for starch to break.
  7. Use a pipette and take a fresh sample every ten seconds and drop into spotting tile. When iodine solution remains browny orange, starch is not present.
35
Q

How to calculate Rate of Reaction?

A

Rate = 1000/time
Units = s^-1

36
Q

Explain the importance of enzyme as biological catalyst?

A

Human body needs to digest food to release energy. Small molecules can be used to build larger molecules that are needed in cells and tissue.

37
Q

Practical : Investigate use of chemicals regents to identify Starch.

A
  1. Add starch in iodine solution.
    If starch present, sample changes colour to dark-black.
    If not present, stays browny-orange
38
Q

Practical : Investigate use of chemicals regents to identify reducing sugar.

A
  1. Add Benedict’s reagent to a sample and heat in water bath.75
  2. If test positive. it will form a colour precipitate.
    Higher the conc of reducing sugar, further the colour changes. Blue->green->yellow->orange->red
39
Q

Practical : Investigate use of chemicals regents to identify lipids (fats).

A
  1. Shake test substance with ethanol until it dissolves.
  2. Pour solution into water
  3. If any lipids present, a precipitate will show up as milky emulsion.
40
Q

Practical : Investigate use of chemicals regents to identify Proteins.

A
  1. Add a few drops of potassium hydroxide solution to make solution alkaline.
  2. Add some copper II sulfate to solution
    If no protein, solution will be blue.
    If protein is present, solution will be purple.
41
Q

Explain how the energy in food can be calculate using calorimetry? (Experiment)

A
  1. Get a food that will burn easily
  2. Weigh it and skewer it on mounted needle
  3. Add a set of volume of water to boiling tube
  4. Measure temp of water, then set fire to food using Bunsen Burner
  5. Hold burning food under boiling tube until it goes out. Relight food again till food wont catch fire.
  6. Measure temp of water again.
42
Q

Explain how the energy in food can be calculate using calorimetry? (Calculations)

A

Energy = Mass of water x Temp change in water x 4.2

Energy = J

Mass of water = g

Temp change = Celsius
THEN
Energy per gram of food = Energy / Mass of food

Energy per gram of food = J/g

43
Q

What is Diffusion?

A

Movement of particles from an area of higher conc to an area of low conc.
Happens in liquid and gas
Only very small molecules can diffuse.
Does not need energy.

44
Q

What is osmosis?

A

Movement of water particles from an area of high conc to low conc through a partially permeable membrane.
Does not need energy.

45
Q

What is active transport?

A

Movement of particles from an area of low conc to high conc against a conc gradient.
Requires energy.

46
Q

Practical : Investigating osmosis in potatoes.

A
  1. Prepare sucrose solution of different ranges
  2. Cut out potato into same sized pieces
  3. Use a balance to measure mass of potatoes
  4. Place potatoes in solution and leave for 40 minutes
  5. Remove potatoes and pat dry gently
  6. Measure the mass of potatoes again
47
Q

Calculate percentage gain and loss in osmosis.

A

Percentage change = (Final mass - Initial Mass)/Initial mass x 100.

Biology Paper 1 (5 decks)

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