B1 - Key Concepts in Biology Flashcards

1
Q

Define

subcellular structures.

A

the different parts of a cell

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2
Q

What is the role of the

nucleus?

A

contains genetic material that controls the activities of the cell

genetic material is arranged into chromosones

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3
Q

What is the

cytoplasm?

A

the gel-like substance where most of the chemical reactions happen, it contains enzymes that control these chemical reactions

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4
Q

What is the role of the

cell membrane?

A

holds the cell together and controls what goes in and out

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5
Q

What are the

mitochondria?

A

where most of the reactions for respiration take place

respiration transfers energy that the cell needs to work

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6
Q

What is the role of the

ribosomes?

A

be involved in the translation of genetic material in the synthesis of proteins

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7
Q

What is the role of the

cell wall?

And what is it made of?

A

it supports the cell and strengthens it

it is made of cellulose

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8
Q

What is the role of the

large vacuole?

A

it maintains the internal pressure to support the cell

it contains cell sap, a weak solution of sugar and salts

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9
Q

What is the role of the

chloroplasts?

A

where photosynthesis occurs, which makes food for the plant

they contain a green substance called chlorophyll

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10
Q

What subcellular structures are found in (most)

animal cells?

(5)

A
  • nucleus
  • cell membrane
  • mitochondria
  • ribosomes
  • (cytoplasm)
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11
Q

What subcellular structures are found in (most)

plant cells?

(8)

A
  • nucleus
  • cell membrane
  • mitochondria
  • ribosomes
  • cell wall
  • large vacuole
  • chloroplasts
  • (cytoplasm)
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12
Q

What subcellular structures are found in (most)

bacterial cells?

(5)

A
  • chromosonal DNA
  • ribosomes
  • cell membrane
  • plasmid DNA
  • flagellum
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13
Q

What is the role of the

chromosonal DNA

in bacterial cells?

A

controls the cell’s activities and replication, it floats free in the cytoplasm

(not a nucleus)

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14
Q

What are the

plasmid DNA

in bacterial cells?

A

small loops of extra DNA that aren’t part of the chromosone

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15
Q

What are the

flagellum

in bacterial cells?

A

long, hair-like structures that rotate to make the bacterium move

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16
Q

Define

specialised cell.

A

a cell that has a structure which makes them adapted to their function

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17
Q

What are the main functions of an

egg cell?

(2)

A
  • carry the female DNA
  • nourish the developing embryo in the early stages
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18
Q

How is an egg cell adapted to its function?

(3 things)

A
  • it contains nutrients in the cytoplasm to feed the embryo
  • it has a haploid nucleus
  • straight after fertilisation, its membrane changes structure to stop any more sperm getting in
19
Q

What is the function of

sperm?

A

transport the male’s DNA to the female’s egg

20
Q

How is a sperm cell adapted to its function?

(4)

A
  • it has a long tail so that it can swim to the egg
  • it has lots of mitochondria in the middle section to provide the energy (from respiration) needed to swim this distance
  • it has an acrosome at the front of the ‘head’, where it stores enzymes needed to digest its way through the membrane of the egg cell
  • it contains a haploid nucleus
21
Q

Define

resolution.

A

how well a microscope distinguishes between two points that are close together

22
Q

What are the benefits of electron microscopes over light microscopes?

(3)

A
  • higher magnification
  • higher resolution
  • let us see the internal structure of mitochondria and chloroplasts
23
Q

How do you calculate

total magnification?

A

eyepiece lens magnification x objective lens magnification

24
Q

What equation links

magnification, image size and actual size?

A

image size = actual size x magnification

25
Q

Define

substrate.

A

the molecule changed in the reaction

26
Q

Define

active site.

A

the part where an enzyme joins on to its substrate to catalyse the reaction

27
Q

What factors affect

enzyme controlled reactions?

(3)

A
  • temperature
  • pH
  • substrate concentration
28
Q

What reaction does the enzyme amalyse catalyse?

A

the breakdown of starch to maltose

29
Q

How would you calculate

rate of reaction?

A

change/time

30
Q

What are

carbohydrases?

And what is an example?

A

enzymes which convert carbohydrates into simple sugars

e.g. amylase

31
Q

What are

proteases?

A

enzymes which convert proteins into amino acids

32
Q

What reaction does lipase catalyse?

A

the conversion of lipids into glycerol and fatty acids

33
Q

What reaction does glycogen synthase catalyse?

A

the joining together of lots of chains of glucose molecules to make glycogen

34
Q

Define

biological molecule.

A

a molecule that is found in a living organism

35
Q

How would you test for

reducing sugars?

(4 steps)

A
  1. Add Benedict’s reagent (which is blue) to a sample
  2. Heat it in a water bath that’s set to 75°C
  3. If there are reducing sugars then a coloured precipitate will be formed
  4. The higher the concentration of reducing sugar, the further the colour change goes

blue -> green -> yellow -> orange -> brick red

36
Q

How would you test for

starch?

(3 steps)

A
  1. Add iodine solution to the test sample
  2. If starch is present, the sample changes from browny-orange to a dark, blue-black colour
  3. If there’s no starch, it stays browny-orange
37
Q

How would you test for

lipids?

(3 steps)

A
  1. Shake the test substance with ethanol for about a minute until it dissolves, then pour the solution into water
  2. If there are any lipids present, they will precipitate out of the liquid and show up as a milky emulsion.
  3. The more lipid there is, the more noticeable the milky colour will be
38
Q

How would you test for

proteins?

(4)

A
  1. Add a few drops of potassium hydroxide solution to make the solution alkaline
  2. Then add some copper(II) sulfate solution (which is bright blue)
  3. If there’s no protein, the solution will stay blue
  4. If protein is present, the solution will turn purple
39
Q

How would you calculate the total amount of energy in the food after calorimetry?

A

energy (J) = mass of water (g) x temperature change of water (°C) x 4.2

40
Q

Define

diffusion.

A

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

41
Q

Define

osmosis.

A

the net movement of water molecules across a partially permeable membrane from an area of higher water potential to an area of lower water potential

42
Q

Define

active transport.

A

the movement of particles across a membrane against a concentration gradient using energy transferred during respiration

43
Q

What is the formula for

percentage change (in mass)?

A

(final mass - initial mass) / inital mass

(x100)