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biology > P1P2B1 - Key concepts > Flashcards

P1P2B1 - Key concepts Flashcards

1
Q

What is Osmosis?

A

The movement of water molecules from an area of high concentration to an area of low concentration across a partially permeable membrane.

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2
Q

What is Active transport?

A

The movement of molecules from an area of low concentration to an area of high concentration against a concentration gradient, using energy from respiration.

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3
Q

What is Diffusion?

A

The movement of molecules from an area of high concentration to an area of low concentration, down a concentration gradient.

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4
Q

What are Prokaryotic cells? Example?

A

Cells without a nucleus. EG - Bacteria

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5
Q

What are Eukaryotic cells? Example?

A

Cells with a nucleus. EG - Animal cell, fungi

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6
Q

How large can Prokaryotic cells be?

A

0.1 - 5.0 Micrometres (μm)

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7
Q

How large can Eukaryotic cells be?

A

10 - 100 Micrometres (μm)

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8
Q

What are key features of Prokaryotic cells?

A
  • Prokaryotic cells may have one or more small rings of DNA, which are called plasmids which can replicate and move between cells so that genetic information is shared.
  • Single DNA loop (Stored in Cytoplasm)
  • No mitochondria or chloroplasts
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9
Q

What are key features of Eukaryotic cells?

A

NA

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10
Q

What 5 sub-cellular structures are found in an animal cell? Functions?

A
  • Nucleus = Stores DNA, controls the cell.
  • Mitochondria = Aerobic Respiration.
  • Cytoplasm = Jelly like substance, where most chemical reactions take place.
  • Cell membrane = Controls what enters and exits, partially permeable.
  • Ribosomes = Protein Synthesis
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11
Q

What are 3 extra sub-cellular structures found in plants but not animal cells? Functions?

A
  • Permanent vacuole = Keeps cell firm and rigid, stores cell sap and water.
  • Chloroplasts = Contains chlorophyll, site of Photosynthesis.
  • Cell wall = Protects and supports the cell, made of cellulose.
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12
Q

What are Plasmids?

A

Small rings/loops of DNA.

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13
Q

What are some structural components of a bacterial cell?

A
  • Single DNA loops
  • Plasmids
  • Flagella
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14
Q

What are the 3 digestive enzymes?

A
  • Amylase
  • Lipase
  • Protease
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15
Q

What is an enzyme?

A

A biological catalyst that speeds up the rate of reactions.

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16
Q

Equation for magnification?

A

Size of image / Size of real object

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17
Q

How does a LIGHT microscope work?

A

A light microscope passes light through a specimen and creates a magnified image using lenses.

18
Q

What was discovered using a light microscope, what was its limitation?

A

Light microscopes allowed bacteria to be seen for the first time.
However, we still could not tell lots of sub-cellular (within the cell) structures apart.

19
Q

How does an ELECTRON microscope work?

A

Electrons are passed through the specimen, creating a magnified image using lenses.

20
Q

What was discovered using an electron microscope?

A

Electron microscopes allowed scientists to see sub-cellular structures more clearly.

They also allowed scientists to study how structures such as mitochondria, chloroplasts and ribosomes function.

21
Q

In what year was the electron microscope first used?

A

1933

22
Q

Describe a light microscope experiment

A

Put a thin sample of tissue (e.g. onion epidermis) onto a microscope slide.

Add a few drops of a suitable stain/dye (e.g. iodine).

Place a coverslip on top of the tissue and place the slide onto the microscope stage.

Use the objective lens with the lowest magnification, and focus on the sample.

Increase the magnification and refocus to see different features of the cell.

23
Q

How do you find the optimal pH for amylase?

A
  • Add amylase to starch solution.
  • Every 30 seconds, take a drop of the mixture and add a drop of iodine solution.
  • Record the total time taken for the iodine solution to stop turning blue when added
  • Repeat this experiment using starch solutions with different pHs.
  • The shorter the time taken for the iodine to stop changing colour, the faster the amylase has broken down the starch and the closer this pH is to amylase’s optimal pH.
24
Q

What does amylase break down? Into what?

A

Starch that breaks down into smaller sugars (Maltose and glucose)

25
Q

What do digestive enzymes do?

A

The digestive enzymes catalyse the breakdown of large, insoluble food molecules into smaller, soluble molecules that are then able to be absorbed into the bloodstream.

26
Q

Where are the sites of amylase?

A

Small intestine (also produced here)
Saliva

27
Q

What does protease break down? Into what?

A

Protease breaks down proteins into amino acid

28
Q

Where are the sites of protease?

A

Small intestine (Also produced here)
Stomach
Pancreas

29
Q

What does lipase break down? Into what?

A

Lipase breaks down lipids into fatty acids + glycerol

30
Q

Why is it necessary to break down large, insoluble food molecules into smaller, soluble molecules?

A

Only small, soluble molecules can be absorbed into the bloodstream and used to construct new carbohydrates, proteins and lipids in the body.
Some glucose produced by digestion is used for respiration.

31
Q

Where is lipase produced?

A

Small intestine
Pancreas

32
Q

Test for starch

A

Iodine solution
Turns blue/black is starch is present

33
Q

Test for sugar

A

Benedict’s solution
Heat for 2 minutes
Turns green/yellow/red if sugar is present

34
Q

Test for calorie content

A

Burn a known mass of the food under a boiling tube filled with a known volume of water.
Calculate the change in temperature of the water.

35
Q

Test for proteins

A

Biuret solution
Turns mauve/purple if proteins present

36
Q

Test for lipids

A

Ethanol
White emulsion (cloudy liquid) will form after shaking if lipids are present

37
Q

What are the key factors affecting rate of diffusion?

A

Membrane surface area
Concentration gradient
Temperature

38
Q

What is concentration gradient?

A

The difference in concentration between 2 areas.

The bigger the difference in concentration, the greater the concentration gradient

39
Q

Describe a test for investigating osmosis affects?

A
  1. Cut discs of raw potato and measure their mass.
  2. Put discs in different concentrations of sugar or salt solution.
  3. After 30 minutes, measure the mass of each disc again.
  4. Calculate percentage change in mass
40
Q

How is active transport applied to a human and a plant?

A

Sugar absorption in gut
Mineral absorption in plant

41
Q
A

biology (9 decks)

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