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Key concepts in biology Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What are eukaryotes?

A

Animals, plants and fungi are eukaryotes. They have a membrane-bound nucleus and their chromosomes are linear rather than circular

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2
Q

What are prokaryotes?

A

Bacteria are prokaryotes. They do not have a membrane-bound nucleus and their DNA is free in the cytoplasm

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3
Q

The different parts of a cell are called what?

A

Subcellular structures

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4
Q

Animal cells have what subcellular structures?

A

Nucleus, cell membrane, mitochondria and ribosomes

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5
Q

What is the nucleus?

A

Contains genetic material, which controls the activities of the cell

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6
Q

What is cytoplasm?

A

Most chemical processes take place here, controlled by enzymes

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7
Q

What is the cell membrane?

A

Controls the movement of substances into and out of the cell

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8
Q

What is mitochondria?

A

Most energy is released by respiration here

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9
Q

What are ribosomes?

A

Protein synthesis happens here

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10
Q

What is a millimetre in standard form?

A

10⁻³

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11
Q

What is a micrometre in standard form?

A

10⁻⁶

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12
Q

What is the cell wall?

A

Strengthens the cell

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13
Q

What is a vacuole?

A

Filled with cell sap, a weak solution of sugar and salts. It maintains internal pressure to support cell

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14
Q

What are chloroplasts?

A

Contain chlorophyll, which absorbs light energy for photosynthesis

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15
Q

What is chromosomal DNA?

A

One long circular chromosome. Controls the cell’s activities and replication. It floats free in the cytoplasm not the nucleus

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16
Q

What is plasmid DNA?

A

Small loops of extra DNA that aren’t part of the chromosome. Plasmids contain genes for things like drug resistance

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17
Q

What is a flagellum?

A

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

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18
Q

What are specialised cells?

A

Cells that are specialised for a particular function

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19
Q

How are sperm cells adapted to their function?

A
  • Acrosome: help the sperm get through the egg’s protective coat and to allow the plasma membranes of the sperm and egg to fuse
  • Flagellum: so it can swim to egg
  • It has lots of mitochondria to provide energy (for respiration) in order to swim
  • Haploid nucleus
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20
Q

How are egg cells adapted to their function?

A
  • It contains nutrients in cytoplasm to feed embryo
  • Haploid nucleus
  • After fertilisation, the membrane changes structure to stop any more sperm from getting in. This makes sure the offspring has the correct amount of DNA
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21
Q

How are ciliated epithelial cells adapted to their function?

A

They are adapted to move substances. They beat to move substances in one direction

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22
Q

What is a haploid cell?

A

Having half the normal number of chromosomes

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23
Q

What is a diploid cell?

A

Having the normal number of chromosomes

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24
Q

Give an example of where ciliated epithelial cells are used in the body?

A

In the lining of the airways contains lots of ciliated epithelial cells. These help to move mucus up the throat so it can be swallowed and doesn’t reach the lungs

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25
Q

What is the formula for total magnification?

A

total magnification = eyepiece lens magnification x objective lens magnification

26
Q

What is the formula for magnification?

A

magnification = image size ÷ real size

27
Q

What is an enzyme?

A

A biological catalyst

28
Q

What does optimum temperature/pH mean?

A

The pH/temperature an enzyme works best at (more frequent collisions between substrate and active site)

29
Q

______ convert proteins into ______ ?

A

a) Proteases b) Amino acids

30
Q

______ convert lipids into ______ and _______?

A

a) Lipases b) Glycerol and fatty acids

31
Q

______ convert starch into ______ ?

A

a) Amylase b) Maltose (and other sugars)

32
Q

What is diffusion?

A

Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration

33
Q

What is osmosis?

A

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

34
Q

What is active transport?

A

Active transport is the movement of particles across a membrane against a concentration gradient (i.e from an area of lower to and area of higher concentration) using energy transferred during respiration

35
Q

What is the formula to calculate rate of reaction for enzyme activity?

A

Rate= 1000÷time

36
Q

What is the formula to find the energy in food (in J)?

A

Energy in food (in J) = Mass of water (in g) x Temperature change of water (in °C) x 4.2

37
Q

What is the formula to find the energy per gram of food (in J/g)?

A

Energy per gram of food (in J/g) = Energy in food (in J) ÷ Mass of food (in g)

38
Q

How does a light microscope work and what can we see using it?

A

They work by passing light through the specimen. They let us see things like nuclei and chloroplasts

39
Q

How does a electron microscope work and what can we see using it?

A

They use electrons rather than light. They have a higher magnification and resolution than light microscopes. They let us see the internal structure of mitochondria and chloroplasts. This allows us to have a greater understanding of how cells work & the role of subcellular structures

40
Q

Explain the mechanism of enzyme action including the active site and enzyme specificity

A

Enzymes only work with one substrate. For the enzyme to work the substrate has to fit into the active site. If the shape doesn’t match then the reaction won’t be catalysed. This is called the `lock and key’ mechanism

41
Q

What does denatured mean in terms of enzymes?

A

The shape of the active site changes so the substrate won’t fit.

42
Q

Explain the effects of temperature, substrate concentration and pH on enzyme activity

A
  • Temperature: A higher temperature increases the rate at first. But if it gets too hot, some of the bonds holding the enzyme together will break.
  • Substrate concentration: The higher the substrate concentration the faster the reaction. This is only true to a certain point as there are so many substrate molecules that the enzymes can’t cope. Adding more makes no difference
  • pH: pH is the same as temperature.
43
Q

Pepsin is an enzyme used to break down proteins in the stomach. What pH does it work best at?

A

pH 2

44
Q

What is the usual pH that enzymes work best in?

A

pH 7

45
Q

Core Practical: Investigate osmosis in potatoes

A

A known mass of potato must be added to sucrose
solution, left for some time, and the final mass
recorded to obtain the percentage change in mass.
This investigation looks at the exchange of water
between the potato and solution and allows the
concentration of sucrose in the potato to be
determined

46
Q

Core Practical: Investigate the effect of pH on enzyme activity

A

This method uses amylase (in solutions of different
pH) to break down starch. The reaction can be
monitored by using iodine to test the presence of
starch in the solution with a continuous sampling
method. To maintain the temperature of the solution,
a Bunsen burner and water beaker must be used
-Repeat with other solutions of different pH values to see how pH affects the time taken for starch to be broken down.

47
Q

You can test for sugars using what practical?

A

Benedict’s Reagent: Add Benedict’s reagent (which is blue) to a sample and heat it in a water bath that’s set to 75°C. If the test’s positive it will form a coloured precipitate (solid particles suspended in the solution).
-The higher the concentration of reducing sugars, the further the colour change goes - you can use this to compare the amount of reducing sugars in different solutions. The colour changes from blue to red.

48
Q

You can test for starch using what practical?

A

Just add iodine solution to sample.

  • If starch is present, the sample changes from browny-orange to a dark, blue-black.
  • If there is no starch present, it stays browny-orange
49
Q

You can test for lipids using what practical?

A

The emulsion test:

  • Shake the test sample with ethanol for about a minute until it dissolves, then pour solution in water.
  • If there ARE any lipids, they will precipitate out of the liquid and show up as a milky emulsion.
  • The more lipids the more noticeable the milky colour will be
50
Q

You can test for proteins using what practical?

A

The biuret test:
-First, add a few drops of potassium hydroxide solution to make the solution alkaline.
-Then add some copper(II) sulphate solution (which is bright blue).
>If there’s NO protein, the solution stays blue.
>If protein is present, the solution will turn purple.

51
Q

Give an example of diffusion in a cell

A

Small molecules such as glucose, amino acids, water and oxygen can diffuse through a cell membranes

52
Q

Explain how the energy contained in food can be measured using calorimetry

A
  • You need food that burns easily, i.e. pasta/dried beans.
  • Weight a small amount of food, then skewer it on a mounted needle.
  • Add set volume of water to a boiling tube (held with a clamp), this will measure energy transferred when the food is burnt.
  • Measure temperature of water, then set fire to the food.
  • Hold food under the boiling tube until it goes out. -Then relight food and hold it under once again.
  • Repeat this until the food won’t catch fire anymore.
  • Finally, measure the water temperature and use appropriate formula to get results.
53
Q

What does calorimetry mean?

A

Food can be burnt to see how much energy it contains

54
Q

Core Practical: Investigate biological specimens using

microscopes

A
  • The object is placed on a rectangular glass slide
  • The slide is placed on a stage with a light source below
  • Light shines through the object and into the objective lens
  • The light passes through the eyepiece lens and from there into your eye
55
Q

What are the different parts of a microscope?

A

Eyepiece lens, high and low power objective lenses, lip, stage, lamp, coarse/fine adjustment knob

56
Q

What does FOV stand for?

A

Field of view

57
Q

How do you create scientific drawings of a specimen?

A
  • Draw outlines of main features, don’t include shading or colouring.
  • Make sure drawing takes up at least half of available space.
  • Label important features and include magnification and a scale.
58
Q

What is a picometre in standard form?

A

10⁻¹²

59
Q

What is a nanometre in standard form?

A

10⁻⁹

60
Q

What does the graph for the osmosis practical look like? Describe what each section shows:

A

It is a curve moving down and right

  • Above x-axis = Higher conc in solution than potato
  • On x-axis = Concentrations are equal
  • Below x-axis = Higher conc in potato than soution
61
Q

What is the formula to find the percentage change in mass?

A

Percentage change = final mass - initial mass
———————————— x 100
initial mass

Biology (10 decks)

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