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Biology > Topic 1 > Flashcards

Topic 1 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Tests for reducing sugars using Benedict’s reagent

A

Add Benedict’s reagent to a sample and let it in water bath to 75°C
No reducing sugars —-> higher concentration
Blue (none) > Green > Yellow > Orange > Brick red

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2
Q

Biuret test for proteins

A 
Add drops of potassium hydroxide solution to make solution alkaline
Add copper (II) sulfate solution
No protein = solution remains blue
Protein = solution turns purple
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3
Q

Emulsion test for lipids

A

Shake sample with ethanol until it dissolves and pour solution into water
If lipids, they will precipitate out of solution as a milky emulsion
More lipids = more noticeable milky colour

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4
Q

Iodine taste for starch

A

Add iodine solution to test sample
If starch, solution changes from brown to black
No starch = remains brown

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5
Q

Energy in food formula (calorimetry)

A

Mass of water (g) * temp change in water (°C) * 4.2

Energy per gram = energy in food (J) / mass of food (g)

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6
Q

Potato cylinder in 0% sucrose solution

A

OSMOSIS
Water concentration is higher in solution
Water molecules move from solution into potato cylinder, from area of high concentration into low concentration of water
Mass of cylinder increases and cells become turgid

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7
Q

Potato cylinder in 80% sucrose concentration

A

OSMOSIS
Water concentration higher in potato cylinder
Water molecules move from potato cylinder into solution, from a high concentration of water to low concentration of water
Mass of cylinder decreases and cells become less turgid/shrink.

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8
Q

Active transport

A

Movement of particles from an area of low concentration to high concentration, up the concentration gradient, using energy transferred in respiration

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9
Q

Diffusion

A

Movement of particles from an area of high concentration to low concentration, down the concentration gradient
A passive process

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10
Q

Nucleus

A

Contains genetic material that controls activities of the cell. Genetic material arranged into chromosomes.

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11
Q

Mitochondria

A

Where most of the reactions for aerobic respiration take place.

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12
Q

Cytoplasm

A

Gel-like substance where most chemical reactions happen. Contains enzymes that control the chemical reactions.

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13
Q

Cell membrane

A

Holds cell together and controls what does in and out.

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14
Q

Ribosomes

A

Involved in translation of genetic material and synthesis of proteins.

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15
Q

Cell wall

A

Made of cellulose, supports and strengthens cell.

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16
Q

Large vacuole

A

Contains cell sap and maintains internal pressure to support cell.

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17
Q

Chloroplasts

A

Where photosynthesis occurs to make food. Contains chlorophyll.

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18
Q

Chromosomal DNA

A

Controls cell’s activities and replication and floats free in the cytoplasm.

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19
Q

Flagellum

A

Long hair-like structure that rotates to make the bacterium move. Used to move away from harmful substances such as toxins and towards beneficial things such as oxygen and nutirents.

20
Q

Plasmid DNA

A

Small loops of extra DNA that aren’t part of the chromosome. Contains genes for things such as drug resistance and can be passed between bacteria.

21
Q

Specialised cell

A

Cells that have structures that make them adapted to their function.

22
Q

How are egg cells adapted to their function

A

Contains nutrients in the cytoplasm to feed embryo.
Haploid nucleus to fuse with other haploid nucleus to make a diploid zygote.
Membrane changes structure after fertilisation to stop any more sperm getting in so offspring have the right amount of DNA.

23
Q

How are sperm cells adapted to their function

A

Long tail so can swim to egg.
Lots of mitochondria in middle section to provide energy to swim.
Acrosome at front of head where enzymes stored to digest through membrane of egg cell.
Contains nutrients in the cytoplasm to feed embryo.
Haploid nucleus to fuse with other haploid nucleus to make a diploid zygote.

24
Q

How are ciliated epithelial cells adapted to their function

A

Line surface of organs and have cilia on their top surface.

Cilia beat to move substances in one direction along surface of tissue.

25
Q

Example where ciliated epithelial cells are

A

Lining of airways have these to move mucus to the throat to be swallowed.

26
Q

Resolution definition

A

How well a microscope distinguishes between two points that are close.

27
Q

Light microscopes

A

Use light to view living cells and can be used to view nuclei and choloroplasts.

28
Q

Electron microscopes

A

Use electrons rather than light and have higher magnification and resolution so things so smaller things such as inside of mitochondria can be viewed.
Can’t be used to view living cells.

29
Q

How to view specimen with light microscope

A

Thin slice of specimen.
Use drop of water to keep specimen in place on slide.
Add stain such as iodine.
Place cover slip and press down so no air bubbles and clip it to stage.
Use coarse adjustment knob to move stage up to lens and looking down eye piece, move stage down until its in focus then adjust with fine adjustment knob until clear.
Use clear ruler to find FOV by measuring diameter visible and switch to high magnification lens if necessary.

30
Q

Total magnification formula

A

Total magnification = eyepiece lens magnification * objective lens magnification

31
Q

Magnification formula

A

Magnification = Image size / Real size

32
Q

Enzyme

A

A biological catalyst that increases the speed of a reaction without being changed or used up.

33
Q

Lock and key mechanism

A

Enzymes only work with one substrate.

For enzyme to work, the substrate has to fit into the active site.

34
Q

Effect of temperature on rate of enzyme-controlled reaction

A

Higher temp increases rate at first.
Optimum point is where enzyme is most active.
If too hot, bonds holding enzyme together break and active site changes shape so substrate won’t fit anymore. Enzyme is denatured.

35
Q

Effect of pH on rate of enzyme-controlled reaction

A

If pH is too high or too low, the pH interferes with bonds holding enzyme together so the shape of active site changes and enzyme is denatured.
Most enzymes have optimum pH of 7 but some that work in the stomach works best at pH 2.

36
Q

Effect of substrate concentration on rate of enzyme-controlled reaction

A

Higher substrate concentration increases rate of reaction as it is more likely that the enzyme will meet up and react with a substrate molecule.
Only true up to a point because all the active sites can become full and adding makes no difference.

37
Q

Investigating effect of pH on enzyme activity

A

Spotting tile with iodine drop in each.
Keep water at 35C and put test tube with 3cm3 of amylase solution and 1cm3 of buffer solution pH 5.
Add starch at sample the amylase every 10 secs using the iodine. Brown means no starch.
Repeat with different pHs and compare how pH affects time taken for all starch to be broken down.

38
Q

Control variables in investigating effect of pH on enzyme activity

A

Concentration and volume of amylase solution.

Temp of water

39
Q

Why does the body have enzymes?

A

The molecules in food are too big to pass through the walls of the digestive system so enzymes break them down into smaller molecules so they pass through the walls of the digestive system easily to enter the blood stream.

40
Q

Why do plants have enzymes?

A

Energy is stored as starch and when the plant needs energy, enzymes break down the starch into sugars that can be respired to release energy.

41
Q

What does carbohyrase break down

A

Carbohydrates into simple sugars

42
Q

What does protease break down

A

Proteins into amino acids

43
Q

What does lipase break down

A

Lipids into glycerol and fatty acids

44
Q

What else can enzymes do?

A

Catalyse reactions that synthesise smaller molecules.

45
Q

How to do calorimetry?

A 
Weigh mass of food and skewer it.
Put set volume of warer in tube.
Measure temp of water and set fire to food and hold food underneath tube.
Relight if necessary.
Measure temp of water
Use formula.

Biology (8 decks)

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