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Biology GCSE > Topic 1 - Key Concepts in Biology > Flashcards

Topic 1 - Key Concepts in Biology Flashcards

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1
Q

What can organisms be?

A

Eukaryotes and prokaryotes

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2
Q

All living things are made up of tiny ____

A

All living things are made up of tiny cells

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3
Q

What are eukaryotic cells?

A

Complex cells

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4
Q

Give examples of types of organisms with eukaryotic cells

A

Plants and animals

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5
Q

What are prokaryotic cells?

A

Smaller and simpler cells

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6
Q

Give examples of types of organisms with prokaryotic cells

A

Bacteria

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7
Q

What are eukaryotes?

A

Organisms made of eukaryotic cells

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8
Q

What are prokaryotes?

A

Prokaryotic cells (single-celled organism)

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9
Q

What are the differents parts of a cell?

A

Subcellular structures

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10
Q

Give examples of subcellular structures in animals cells?

A 
A nucleus
Cytoplasm
A cell membrane
Mitochondria
Ribosomes
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11
Q

What is a nucleus?

A

A subcellular structure that contains genetic material that controls the activites of the cell

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12
Q

What is cytoplasm?

A

A gel-like substance where most of the chemical reactions happen

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13
Q

What can be found in the cytoplasm?

A

Enzymes

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14
Q

What is the cell membrane?

A

The membrane around the cell which holds the cell together and controls what goes in and out of the cell

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15
Q

What are mitochondria?

A

The place where most reactions for respiration take place

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16
Q

What are ribosomes?

A

The structure involved in the translation of genetic material in the synthesis of proteins

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17
Q

What are the subcellular structures found with plant cells?

A

A nucleus, cytoplasm, a cell membrane, mitochondria, ribosomes, a cell wall, a vacuole and chloroplasts

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18
Q

What is the cell wall?

A

A wall around the cell made of cellulose which supports and strengthens the cell

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19
Q

What is the vacuole?

A

A structure which contains cell sap, a weak solution of sugar and salts.
It also helps maintain internal pressure of the cell

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20
Q

What are chloroplasts?

A

Structures where photosynthesis occurs which makes glucose for the plant

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21
Q

What do chloroplasts have inside them?

A

A green substance called chlorophyll

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22
Q

Bacterial cell’s have no _____

A

Bacterial cell’s have no nucleus

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23
Q

Bacterial cell’s have ____ nucleus

A

Bacterial cell’s have no nucleus

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24
Q

Compare the size of bacterial cells to animal and plant cells

A

Bacterial cells are a lot smaller than plant and animal cells

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25
Q

What are the subcellular structures found within bacterial cells

A 
Chromosomal DNA
Ribosomes
A cell membrane
Plasmid DNA
A flagellum
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26
Q

What is chromosomal DNA?

A

One long circular chromosome which controls the cell’s activities and replication
It floats free in the cytoplasm (not in a nucleus, as there is no nucleus)

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27
Q

What is plasmid DNA?

A

Small loops of extra DNA that aren’t part of the chromosome

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28
Q

What does plasmid DNA contain genes for?

A

Drug resistance

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29
Q

True or False? Bacteria can’t pass genes as there are no genes?

A

False, plasmid DNA can be passed between bacteria

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30
Q

What is a flagellum?

A

A long, hair-like structure that rotates to make the bacterium (enables cell movement)

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31
Q

What is the use of a flagellum for a bacterium?

A

To move the bacteria away from harmful substances like toxins and towards beneficial things like nutirents or oxygen

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32
Q

Describe the function of the nucleus

A

Contains the genetic material that controls the activity of the cell

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33
Q

Describe the function of the mitochondria

A

Where most of the reactions for respiration take place

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34
Q

Describe the function of ribosomes

A

The structure involved in the translation of genetic material in the synthesis of proteins

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35
Q

True or false? Multicellular organisms contain lots of different types of cells?

A

True

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36
Q

What are specialised cells?

A

Cells that have a structure which makes them adapated to their function

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37
Q

Give examples of specialised cells?

A

Egg, sperm and ciliated epithelial cells

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38
Q

What are sperm and egg cells specialised for?

A

Reproduction

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39
Q

Why is it important the egg and sperm clel have the right number of chromosomes?

A

So the fertilised egg has the normal amount for a human

If not, the offspring will have a disabillity

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40
Q

What is the main function of an egg?

A

To carry the female DNA and to nourish the developing embryo in it’s early stages

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41
Q

How is the human egg cell adapted to its function?

A

By containing nutrients in the cytoplasm to feed the embryo
By having a haploid nucleus
Straight after fertillisation its membrane changes structure to stop any more sperm getting in. This makes sure the offspring ends up with the right amount of DNA

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42
Q

What is the main function of a sperm cell?

A

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

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43
Q

How is the sperm cell adapted to its function?

A

By having a long tail so it can swim
By having a lots of mitochondria in the middle section to provide the energy needed to swim
By having an acrosome at the front of the head where it stores enzymes needed to digest through the membrane of the egg cell
By having a haploid nucleus

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44
Q

What are ciliated epithelial cells specialised for?

A

Moving materials

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45
Q

Where can ciliated epithelial cells be found?

A

On the lining of organs

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46
Q

What do ciliated epithelial cells often have on the surface?

A

Cillia

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47
Q

What are cillia?

A

Hair-like structures

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48
Q

How is ciliated epithelial cells adapted to its function?

A

The cillia beat to move substances in one direction

Found in areas of high traffic (lining of the airways)

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49
Q

What are cells often studied using?

A

Microscopes

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50
Q

How do microscopes work?

A

They use lenses to magnify images

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51
Q

What are the main goals of microscopes?

A

To magnify and increase the resolution of the image

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52
Q

Define resolution

A

How well a microscope can distinguish between two points that are close together

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53
Q

How do light microscopes work?

A

By passing light through the specimen

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54
Q

What can you see with a light microscope?

A

Nuclei and chloroplasts

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55
Q

True or False? You can’t look at living specimens through a light microscope because the light will kill them?

A

False, you can use it to view living specimens

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56
Q

How do electron microscopes work?

A

By firing electrons through the specimen

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57
Q

What can you see with an electron microscope?

A

The internal structure of mitochondria and chloroplasts

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58
Q

What can you see with an electron microscope?

A

The internal structure of mitochondria and chloroplasts

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59
Q

What are the rules of scientific drawing?

A 
Use a sharp pencil
Draw outlines
Don't colour or shade
Label all the important features
Include the magnificaton used
Include the scale
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60
Q

What is magnification?

A

How many times bigger the image is

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61
Q

What is the total magnification equation?

A

Total magnification = Eyepiece lens magnification x Objective lens magnification

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62
Q

What is the magnification equation?

A

Magnification = Image size / Real size

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63
Q

State the way to remember the magnification formula?

A

I AM

I = A x M

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64
Q

What is the standard form for milli?

A

x10^-3

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65
Q

What is the standard form for micrometre?

A

x10^-6

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66
Q

What is the standard form for micro?

A

x10^-6

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67
Q

What is the standard form for nano?

A

x10^-9

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68
Q

What is the standard form for pico?

A

x10^-12

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69
Q

Calculate the length of a cell which has an image size of 7 x 10^-1mm under a magnification of x400
Write you answer in μm

A

7 x 10^-1mm x 10^3 = 7 x 10^2

Actual size = Image size / Magnification
AS = 7 x 10^2 / 400
AS = 1.75 μm

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70
Q

What are enzymes?

A

Catalysts produced by living things

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71
Q

Why do organisms need enzymes?

A

Because the reactions need to be carefully controlled, to get the right amount of substances
And the reactions that need to take place require extremely high temperatures which would be impossible within the body
And if you were to raise the temperature, other less useful and sometimes harmful reactions would take place

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72
Q

Enzymes have _________ so they can catalyse reactions

A

Enzymes have special shapes so they can catalyse reactions

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73
Q

What do chemical reactions usually involve?

A

Things being split apart or joined together

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74
Q

What is the substrate?

A

The molecule changed in the reaction (reactant)

75
Q

What does every enzyme have?

A

An active site

76
Q

What is an active site?

A

The part where an enzyme joins onto its substrate to catalyse the reaction

77
Q

Enzymes usually only work with ___ substrate

A

Enzymes usually only work with one substrate

78
Q

What are enzymes said to have for their substrate?

A

A high specificity

79
Q

Why do enzymes have a high specificity to its enzyme?

A

Because for the substrate to be catalysed it must fit into the unique enzymes’ active site which means that the active site on the enzyme will only fit that substrate

80
Q

What three factors affect the rate of reaction?

A

Temperature
pH
Substrate concentration

81
Q

How does temperature affect the rate of reaction?

A

Heating it at first increases the rate, however, too high of temperature will denature the enzyme

82
Q

How does pH affect the rate of reaction?

A

Too high or too low of a pH will break the bonds holding the enzyme together
There will be an optimum pH at which the enzymes rate is at its fastest

83
Q

How does substrate concentration affect the rate of reaction?

A

As you increase the concentration of the substrates, the rate of reaction also increases, however, there will be a point where the limiting factor is no longer substrate concentration instead it is now number of open active sites

84
Q

Explain why enzymes have an optimum pH?

A

If the pH is too high or too low, it can interfere with the bonds holding the enzyme together. This changes the shape of the active site leading to the denaturing of the enzyme

85
Q

When investigating the effect of pH on enzyme activity, what enzyme is used?

A

Amylase

86
Q

What is amylase?

A

An enzyme which catalyses the breakdown of starch to maltose (sugar)

87
Q

How do you test for starch?

A

By using iodine solution

88
Q

What is the colour change when testing for starch?

A

Browny-orange to blue-black

89
Q

When investigating the effect of pH on enzyme activity, what temperature should you use?

A

Around 35*c

90
Q

When investigating the effect of pH on enzyme activity, what must you add to a test tube?

A 
Amylase solution
Buffer solution (pH of 5)
91
Q

When investigating the effect of pH on enzyme activity, why shouldn’t you use the same syringe?

A

Some of the previous chemicals may of not fully left the syringe meaning the reaction will begin early if you were to mix the reactants causing in accurate results

92
Q

When investigating the effect of pH on enzyme activity, what is the main method used?

A

Continous sampling

93
Q

When investigating the effect of pH on enzyme activity, how do you know when all the starch has been converted?

A

The iodine solution doesn’t change (remains browny-orange)

94
Q

When investigating the effect of pH on enzyme activity, how do you know when all the starch has been converted?

A

The iodine solution doesn’t change (remains browny-orange)

95
Q

When investigating the effect of pH on enzyme activity, what do you change when doing repeats?

A

The pH of the buffer solution

96
Q

When investigating the effect of pH on enzyme activity, what is the independent variable?

A

The pH of the buffer solution

97
Q

When investigating the effect of pH on enzyme activity, what is the dependent variable?

A

Time taken for amylase to break down all of the starch

98
Q

What is the rate of reaction equation?

A

1000/time

99
Q

What are the units of rate of reaction?What are the units of rate of reaction?

A

s^-1

100
Q

What is a rate?

A

A measure of how much something changes over time

101
Q

Examples of big molecules that the body use are ____, ____ and ____

A

Examples of big molecules that the body use are carbohydrates, lipids and proteins

102
Q

Why is it important that organisms break the larger molecules into smaller molecules?

A

So they can be used for growth and other life processes

And some are too big to be moved around the body

103
Q

Give an example of a use that a plants uses starch for

A

Storage of energy

104
Q

What does a plant do when it needs stored energy?

A

It’s enzymes break down the starch into sugar which can be respired to release

105
Q

What enzymes break down carbohydrates?

A

Carbohydrases

106
Q

What do carbohydrases break down?

A

Carbohydrates

107
Q

What do carbohydrates get broken down into?

A

Simple sugars

108
Q

Give an example of a carbohydrase

A

Amylase

109
Q

What enzymes break down proteins?

A

Proteases

110
Q

What do proteases break down?

A

Proteins

111
Q

What do proteins get broken down into?

A

Amino Acids

112
Q

What enzymes break down lipids?

A

Lipases

113
Q

What do lipases break down?

A

Lipids

114
Q

What do lipids break down into?

A

Glycerol and fatty acids

115
Q

An enzyme-controlled reaction was carried out at pH 4
After 60 seconds 33cm^3 had been released
Calculate the rate of reaction cm^3 s^-1

A

33/60=0.55 cm^3 / s^-1

116
Q

Name the molecules that result from the breakdown of carbohydrates

A

Simple sugars

117
Q

Name the molecules that result from the breakdown of proteins

A

Amino Acids

118
Q

What do you use to test for sugars?

A

Benedicts reagent

119
Q

How do you test for sugars?

A

Add benedicts reagant to the sample and heat it in a water bath thats set to 75*C
If the test is positive a coloured precipitate will form

120
Q

What colour is benedicts reagant before contact with sugar?

A

Blue

121
Q

State the colour change order for benedicts reagent?

A

Blue -> Green -> Yellow -> Orange -> Red

122
Q

What is the test for starch?

A

Iodine

123
Q

How do you test for starch?

A

Add iodine to the sample

124
Q

Describe the colour change for a positive iodine starch test

A

From browny orange to bluey black

125
Q

What is the name of the test for lipids?

A

The emulsion test

126
Q

How do you test for lipids?

A

Shake the test substance with ethanol for about a minute until it dissolves then pour the solution into water
If lipids are present there will be a milky emulsion

127
Q

Describe the positive test for lipids

A

Milky precipitate

128
Q

What solutions do you add to proteins?

A

Potassium hydroxide and copper(ii) sulfate

129
Q

How do you test for proteins?

A

Add drops of potassium hydroxide to make the solution alkaline
Then add some copper sulfate solution

130
Q

Describe the positive result for the biuret test

A

If protein is present, solution will turn purple

If protein not present, solution will remain blue

131
Q

What colour is copper(ii) sulfate?

A

Blue

132
Q

During the biueret test why do you add potassium hydroxide?

A

To make the solution alkaline

133
Q

A solution was mixed with potassium hydroxide and copper(ii) sulfate solution turns purple
What conclusion do you draw from this test?

A

Proteins are present

134
Q

When calculating energy in food, what type of food must you have?

A

Dry

135
Q

When calculating energy in food, what must you do first?

A

Weigh the food

136
Q

When calculating energy in food, after weighing the food what must you do?

A

Add a set volume of water

137
Q

When calculating energy in food, what must you measure?

A

The temperature of the water before and after

138
Q

When calculating energy in food, where do you hold the burning food?

A

Underneath the water in the tube with the thermometer

139
Q

How do you calculate the energy in food?

A 
E = M x T x 4.2
Energy = Mass x Temperature x 4.2
Joules = g x *c x 4.2
140
Q

How do you calculate the energy per gram of food?

A

Energy per gram of food = Energy in food / Mass of food

J/g = J / g

141
Q

A student burned 0.2g of popcorn under 20cm^3
During the experiment the temperature of the water increased by 28.6*C when the popcorn was burnt
Calculate the energy per gram of food?

A 
E = M x T x 4.2
E = 0.2 x 28.6 x 4.2
E = 2,402.4 J

Energy per gram = 2402.4 / 0.2
Energy per gram = 12,012 J/g

142
Q

A student burned 0.5g of popcorn under 20cm^3
During the experiment the temperature of the water increased by 38.7*C when the popcorn was burnt
Calculate the energy per gram of food?

A 
E = M x T x 4.2
E = 0.5 x 28.6 x 4.2
E = 3250.8 J

Energy per gram = 3250.8 / 0.5
Energy per gram = 6,501.6 J/g

143
Q

A student performed a calorimetry experiement on a small piece of bread
Why is it important to record the increase in temperature as soon as possible after the bread is burnt in this experiment?

A

To minimise the amount of energy loss to the surroundings

144
Q

Define diffusion

A

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

145
Q

Diffusion happens in both ______ and ____

A

Diffusion happens in both liquids and gases

146
Q

Define osmosis

A

The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration

147
Q

What is a partially permeable membrane?

A

A membrane with very small holes in it

148
Q

Define active transport

A

The movement of particles across a semi-permable membrane from an area of lower concentration to an area of higher concentration through the use of energy

149
Q

True or False? All three; diffusion, active transport and osmosis are passive?

A

False, active transport requires energy

150
Q

Give two differences between the processes of diffusion and active transport

A

Diffusion is passive whilst active transport requires energy (is active)
Diffusion goes down a concentration gradient, whereas, active transport goes up a concentration gradient

151
Q

When investigating osmosis, what do you put in the sucrose?

A

Potato cylinders

152
Q

When investigating osmosis, how long do you leave the cylinders in the solution?

A

For atleast 40 minutes

153
Q

When investigating osmosis, what do you record?

A

The mass of the potatoes before and after

154
Q

When investigating osmosis, what is the independent variable?

A

The sucrose solution concentration

155
Q

When investigating osmosis, what is the dependent variable

A

The mass of potato cylinders lost

156
Q

When investigating osmosis, what are some examples of control variables?

A

Volume of the sucrose, size of the potato cylinders and type of the potatoes

157
Q

What do we call it when both solutions have the same concentration of water?

A

Isotonic

158
Q

When investigating osmosis, on the graph what does a positive percentage change in mass represent?

A

The sucrose solutions concentration is higher than in the cylinders so the chips gain mass as water through osmosis

159
Q

When investigating osmosis, on the graph what does a negative percentage change in mass represent?

A

The sucrose solutions concentration is lower than in the cylinders so the chips lose mass as water through osmosis

160
Q

When investigating osmosis, on the graph what does no percentage change in mass represent?

A

That the solutions are isotonic (same water concentration)

161
Q

A group of potato cubes were placed in a sucrose solution and left for one hour
The cube weighed 13.3g at the start and 11.4g at the end
Calculate the percentage change in mass

A 
% = (Change / Original) x 100
% = (11.4-13.3 / 13.3) x 100
% = -14.3%
162
Q

What is the function of the cell membrane?

A

Hold the cell together and control what goes in and out

163
Q

Give three structures found in plant cells but not in animal cells

A

Vacuole
Cell Wall
Chloroplasts

164
Q

Name the subcellular strucutre in plant cells where photosynthesis takes place

A

Chloroplasts

165
Q

Name two structures that are found in both prokaryotic cells and eukaryotic cells

A

Ribosomes and cell membrane

166
Q

What does the term haploid mean?

A

Half the number of chromosomes of that respective organism

167
Q

Give three way in which a human egg cell is adapated to its function

A

Membrane locks after fertilisation to ensure offspring has correct number of chromosomes
Contains nutrients to nourish early stages of embryo
Haploid nucleus to ensure offspring has correct number of chromosomes

168
Q

What are cilia?

A

Hair-like structures on the top surface of ciliated epithelial cells

169
Q

Give an advantage of an electron microscope over a light microscope

A

An electron has a bigger magnification than a light one whilst also having a better resolution

170
Q

Why is it necessary to use thin samples with a light microscope?

A

The light microscope relies on shining light through the specimen
Therefore, if the specimen is too thick the light won’t be able to get through the specimen

171
Q

Write the equation you would use to find the size of a specimen using the magnification used and the size of the image seen through a microscope lens

A

Image Size / Magnification = Actual Size

172
Q

Describe how you would convert mm to μm?

A

x 1000

173
Q

What part of an enzyme makes it specific to a particular substrate?

A

It’s active site

174
Q

Why can denatured enzymes no longer catalyse chemical reactions?

A

Because the substrate will no longer be able to fit into the enzyme

175
Q

Explain how temperature affects enzyme activity

A

As temperature increases enzyme activity increases until the bonds between the enzyme begin to break further denaturing the enzyme

176
Q

Describe how you could investigate the effect of pH on the rate of amylase activity?

A

Every 10 seconds add a sample of a solution mixed with a buffer solution with a pH, amylase and starch.
Time how long it takes for the starch to be broken down fully
Repeat with different pH solutions

177
Q

Which two molecules are produced when lipids are broken down?

A

Fatty and glycerol molecules

178
Q

Name a big molecule that’s formed from simple sugars

A

Starch

179
Q

Describe the colour change that occurs when benedicts reagent is added to a substance containing sugars

A

Blue -> Green -> Yellow -> Orange -> Red

180
Q

What chemical reagent is used to test for the prescence of starch?

A

Iodine

181
Q

How would you test for the presence of lipids in a sample?

A

Shake the substance whilst pouring ethanol until it dissolves then pour the solution into water
Milky water as positive

182
Q

Describe briefly how you could use calorimetry to measure the energy content of a peanut

A

Add a set volume of water to a test tube
Heat dry food
Calculate temperature change of water
Use equation: E=MxTx4.2

183
Q

If a potato cylinder is placed in a solution with a very high sucrose concentration, what will happen to the mass of the potato cylinder over time?
Explain why?

A

Mass of potato will decrease
As there will be higher concentration of water in potato than the solution so the water will move down the concentration gradient

Biology GCSE (9 decks)

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