Key Concepts Flashcards

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1
Q

What Is a Eukaryotic cell!?

A

contains a nucleus and other structures.
They are surrounded by membranes

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2
Q

What type of microscope can you see mitochondria with!?

A

A light microscope but not in detail

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3
Q

What type of microscope can you see ribosomes with!?

A

An electron Microscope

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4
Q

What is the function of CYTOPLASM in an animal cell!?

A

contain dissolved nutrients, salts and organelles.

Many chemical reactions occur here!!!!

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5
Q

What is the function of a NUCLEUS in plant and animal cells!?

A

Contains genetic material including DNA, which controls cell activity

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6
Q

What is the function a a cell membrane in plant and animal cells!?

A

Permeable to some substances

Controls the movement of substances which go in and out of the cell

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7
Q

What is the function of MITOCHONDRIA in plant and animal cells?

A

contain the enzyme for respiration

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8
Q

What is the function of RIBOSOMES in plant and animal cells!?

A

They are tiny structures and protein synthesis occurs here!

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9
Q

Are plant cells Eukaryotic or prokaryotic!?

A

Eukaryotic

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10
Q

What 4 structures do both plant and animal cells share!?

A

-a nucleus
-a cell membrane
-mitochondria
-ribosomes

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11
Q

What 8 structures do plant cells contain!?

A

Cytoplasm

A nucleus

Cell membrane

Mitochondria

Chloroplast

A cell wall

A permanent vacuole

Ribosomes

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12
Q

What do 8 structures do plant cells contain!?

A

A nucleus

A cell membrane

Chlorophyll

Mitochondria

Ribosomes

Chloroplast

Cell wall

Permanent vacuole

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13
Q

What is the function of CHLOROPLAST in a plant cell!?

A

contains the green pigment (chlorophyll) which absorbs the light energy.

Contains the enzymes needed for photosynthesis.

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14
Q

What is the function of CHLOROPHYLL in a plant cell!?

A

Green pigment that absorbs light energy

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15
Q

What is the function of THE CELL WALL in a plant cell!?

A

Provides structure and protection

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16
Q

Does an animal cell contain a cell wall!?

A

No

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17
Q

Does a bacterial cell contain a cell wall!?

A

Yes-not made form cellulose

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18
Q

What is the function of the PERMANENT VACUOLE in a plant cell!?

A

Is filled with cells that help to keep the cell’s shape.

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19
Q

Do animal cells contain a permanent vacuole!?

A

No- but they may contain one that is Small and temporary

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20
Q

Are bacterial cells Eukaryotic or Prokaryotic!?

A

Prokaryotic- they are single celled

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21
Q

What is a prokaryotic cell!?

A

does not contain a nucleus or any other structures
none are surrounded by membranes

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22
Q

Are bacterial cells visible underneath a microscope!?

A

Only larger bacteria are visible underneath a light microscope

HOWEVER……

Electron microscopes would be needed to see the cell in detail.

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23
Q

What structures do plant, animal and bacterial cells share!?

A

Cytoplasm
Cell membrane

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24
Q

What is the function of CHROMOSOMAL DNA in a bacterial cell!?

A

The same as DNA
not contained by a nucleus it is found loose in the cytoplasm

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25
Q

What is the function of PLASMID DNA in a bacterial cell!?

A

Are small, closed-circles of DNA that are present in the cytoplasm

They can move from one bacterial cell to another unlike CHROMOSOMAL DNA . This provides variation

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26
Q

What is the function of the FLAGELLA in a bacterial cell!?

A

They rotate OR move in a whip like motion to move the bacterium.

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27
Q

What is the word of one flagella!?

A

Flagellum

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28
Q

What is the function of the CELL WALL in a bacterial cell!?

A

Provides protection- isn’t made from cellulose

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29
Q

How do bacterial cells duplicate!?

A

They copy themselves by binary fission

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30
Q

What is binary fission!?

A

Very similar to mitosis but as the cell is PROKARYOTIC it is given a different name

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31
Q

How big is a EUKARYOTIC CELL!?

A

Between 5um-100um.

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32
Q

How big is a PROKARYOTIC cell!?

A

Between 0.2um-2.0um.

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33
Q

What are the outer layers of a EUKARYOTIC cell!?

A

Cell membrane which is surrounded by a cell wall ( cell wall=plants a fungi)

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34
Q

What are the outer layers of a PROKARYOTIC cell!?

A

A cell membrane surrounded by a cell wall

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35
Q

What structures does a EUKARYOTIC cell contain!?

A

Cytoplasm
Mitochondria
Chloroplast (plants)
Ribosomes

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36
Q

What structures do PROKARYOTIC cells contain!?

A

Cytoplasm
Ribosomes

NO….
mitochondria
Chloroplast

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37
Q

Where is the genetic material found in a EUKARYOTIC cell!?

A

-DNA found in the nucleus

  • plasmids are found in a few eukaryotic organisms
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38
Q

Where is the genetic material found in a PROKARYOTIC cell!?

A

-DNA is is a single molecule:found free in the cytoplasm
- additional DNA found in plasmids

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39
Q

What is a plasmid!?

A

One or more rings of DNA

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40
Q

What type of cell division occurs in a EUKARYOTIC cell!?

A

Mitosis

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41
Q

What type of cell division occurs in a PROKARYOTIC cell!?

A

Binary fission

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42
Q

What is a specialised cell!?

A

Each cell is specialised to carry out a particular role to ensure the organism functions as a whole

-animals and plants therefore consist of many different types of cells working together

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43
Q

Name 2 examples of a specialised animal cell!?

A

Egg and sperm

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44
Q

Is a sperm cell HAPLOID or DIPLOID!?

A

Haploid

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45
Q

What is found in the HEAD of a sperm cell!?

A

Contains genetic material for fertilisation in HAPLOID nucleus

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46
Q

What is found in the ACROSOME of a sperm cell!?

A

Contains enzymes that sperm can penetrate egg

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47
Q

Where is the ACROSOME in a sperm cell found!?

A

In the head

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48
Q

What is found in the MIDDLE PIECE of a sperm cell!?

A

It is packed with mitochondria which are used to release energy needed to swim to and fertilise the egg

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49
Q

What is the use of the TAIL on a sperm cell!?

A

It enables the sperm to swim

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50
Q

Name a Fact about sperm cells……..

A

Sperm are the smallest cell in the human body and millions are made

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51
Q

What does an EGG cell contain!?

A

Cytoplasm
HAPLOID nucleus
Cell membrane

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52
Q

What is the job of the CYTOPLASM in an EGG cell!?

A

Contains nutrients for growth of the early embryo

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53
Q

What is the job of the HAPLOID nucleus in an EGG cell!?

A

Contains the genetic material for fertilisation

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54
Q

What is the job of the CELL MEMBRANE in an EGG cell!?

A

Changes after fertilisation by a single sperm so that no more sperm can enter

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55
Q

Fact about EGG cells……

A

Egg cells are one of the largest cells in the body and only a few are made

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56
Q

What are the job of the CILIA in a CILIATED EPITHELIAL CELL!?

A

Cilia are found on the surface and Beat to move fluids and particles up the trachea.

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57
Q

What are light microscopes used for!?

A

Used to study living cells and are for regular use when magnitude and resolution is relatively low

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58
Q

What are electron microscopes provide!?

A

Provide higher magnification and resolution images

Cannot used to see living cells

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59
Q

When was the first microscope discovered!?

A

It is unknown

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60
Q

What year was the compound microscope made in!?

A

1590s

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61
Q

Who invented the compound microscope!?

A

Dutch spectacle maker- Janssen

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62
Q

What was the compound microscope!?

A

Lenses in tubes

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63
Q

What is the magnification of the compound microscope thought to be!?

A

Between x3 and x9

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64
Q

How was he compound microscope used in the 1650s!?

A

It was used to observe and draw cells

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65
Q

Who used the compound microscope in the 1650s!?

A

Robert Hooke

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66
Q

Who created a microscope with a single spherical lens!?

A

Antonie Van Leeuwenhoek

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67
Q

What magnification did the single spherical lens microscope have!?

A

x275

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68
Q

What is the maximum magnification of a light microscope!?

A

x2000

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69
Q

What is the top magnification of a light microscopes when being used in schools!?

A

x400

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70
Q

What is the calculation for the MAGNIFICATION of a LIGHT microscope!?

A

Magnification of eyepiece x magnification of objective

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71
Q

What is the calculation for the magnification of an image when using a LIGHT microscope!?

A

Size of image
————————-
Real size of object

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72
Q

What is the only important factor to viewing cells!?

A

Magnification

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73
Q

Other than magnification what is another important factor when viewing cells with a light microscope!?

A

Resolution

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74
Q

What is the resolution!?

A

The detail that can be seen

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75
Q

The greater the detail in an image depends on what!?

A

Resolution or resolving power

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76
Q

What is the resolution of a light microscope!?

A

Around 2um OR 200nm

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77
Q

What does this resolution number mean!?

A

It Means it cannot distinguish points closer than 200nm

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78
Q

What does nm stand for!?

A

Nanometre

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79
Q

How much of a meter is a nanometre!?

A

1 billionth

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80
Q

How is one nanometre written as!?

A

1x10-9m or 1/1000 000 000

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81
Q

What does an election microscope use to see an image!?

A

Uses a beam of electrons instead of a ray of light.

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82
Q

What cannot be observed with an electron microscope!? And why!?

A

Living cells

because samples are placed into a vacuum

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83
Q

What are the 2 types of electron microscope!?

A

TEM: transmittion electron microscope
SEM: scanning electron microscope

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84
Q

What is a TEM microscope used to examine!?

A

Thin slices or sections of cells or tissues

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85
Q

How big is the depth of field in an SEM and what is it used for!?

A

Large depth of field

Used to examine the surface structure of specimens

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86
Q

What is the maximum magnification of a TEM!?

A

Around x1 000 000

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87
Q

What does this large magnification of a TEM mean!?

A

Images can be enlarged beyond that photographically

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88
Q

What is the limit resolution of an TEM!?

A

Less that 1nm

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89
Q

What does the 1nm resolution reveal!?

A

Structures that are not visible with a light microscope

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90
Q

What is the magnification of a SEM!?

A

Up to x30 000

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91
Q

What is the limit of resolution of an SEM microscope!?

A

Lower than a TEM at around 50nm

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92
Q

What are enzymes!?

A

Enzymes are proteins that function as biological catalysts

They are molecules that speed up a chemical reaction without being changed themselves

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93
Q

What shape are enzymes!? And what do they allow!?

A

Folded complex 3D shapes

allow smaller molecules to fit into them

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94
Q

What is the place where the molecules fit into the enzyme called!?

A

The active site

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95
Q

In the lock and key hypothesis what 2 shapes match together!?

A

The shape of the active site matches with the site of the substrate

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96
Q

What makes the enzyme highly specific!?

A

The active site shape and the substrate shape match together

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97
Q

How many types of reaction can an enzyme catalyse in!?

A

Usually one but some catalyse by a few types of reactions

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98
Q

What is the first step not the lock and key process!?

A

The substrate collides with the active site of the enzyme and becomes attached to the

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99
Q

What does the active site have to the substrate on the first step of lock and key!?

A

A complementary shape

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100
Q

What is the second step of the lock and key hypothesis!?

A

Enzyme catalyst breaks down the substrate

101
Q

How can the fit between the enzyme and the substrate be described!?

A

As a perfect fit between the lock and key

102
Q

What is the third step of the lock and key process!?

A

Products and still released from the active site

103
Q

Describe the enzyme molecule at the end of the lock and key process…..

A

Unchanged meaning it can be reused

104
Q

What 2 factors changes the shape of the active site!?

A

PH
Temp

105
Q

What is a result of these factor changes!?

A

The substrate no longer fits into the enzyme resulting in the enzyme becoming denatured
Meaning the key won’t fit the lock

106
Q

What is the calculation of the rate of an enzyme catalysed reaction!?

A

Rate of reaction= amount of substrate used OR the amount of product formed
————————————————————————————————
Time taken

107
Q

What happens to the rate of an enzyme-catalyst reaction when temperature increases!?

A

It also increases

108
Q

What happens to the rate of an enzyme-catalysed reaction at high temperatures!?

A

It decreases as enzyme becomes denatures and can not longer function.

109
Q

As the temperature increase what also increases!? (Enzymes)

A

The rate of enzyme activity

110
Q

When is the OPTIMUM activity reached!?

A

At the enzyme’s optimum temperature

111
Q

A continued increase in temperature results in what!? (Enzymes)

A

A sharp decrease in activity as the enzyme’s active site changes shape and becomes denatured

112
Q

What does a change in pH alter in enzymes!?

A

The shape of the enzymes active site

113
Q

What does the optimum ph depend on for each enzyme!?

A

It depends on where the enzyme usually works

114
Q

Name 2 examples of an enzyme and there ph

A

Small intestine: pH of around 7.5

Stomach: pH of around 2

115
Q

As pH increases what also increases!?

A

Enzyme activity

116
Q

As optimum activity is reached what other optimum is reached in terms of Ph

A

Enzymes optimum Ph is also reached

117
Q

If a continued increase of pH occurs what will happen to the enzymes activity!?

A

A sharp decrease in activity and active site will change shape resulting the enzyme becoming denatured

118
Q

Enzymes will work best if…….

A

There is a high substrate concentration

119
Q

As the substrate concentration increases what also increases!?

A

Enzyme activity

120
Q

Why will the rate of enzyme activity not last forever!?

A

Because a point will be reached when the enzyme becomes saturated and no more substrates can fit at any one time even though there is plenty of substrate available

121
Q

What is reached at the enzyme’s optimum substrate concentration!?

A

An optimum rate

122
Q

What does a continued increase in substrate concentration result in!?

A

The same amount of activity as there a not enough enzyme molecules available to break down the excess substrate molecules

123
Q

What is food made out of!?

A

Large insoluble molecules

124
Q

Name the 3 large molecules needed for growth, repair and metabolism

A

Carbohydrates
Proteins
Lipids

125
Q

Name the 3 things carbohydrates, proteins and lipids are used for……

A

Growth
Repair
Metabolism

126
Q

Where are carbohydrates, proteins and lipids found!?

A

In food

127
Q

Why are digestive enzymes needed to break down c,p,l!?

A

Because the molecules are to large to pass from the intestine to the blood

128
Q

Name 4 examples of a carbohydrate

A

Glycogen
Starch
Sucrose
Glucose

129
Q

What is the building block of a carbohydrate!?

A

A monosaccharide

130
Q

What is a monosaccharide!?

A

A simple sugar such as glucose and a fructose

131
Q

Enzymes join monosaccharides together to for what!?

A

Disaccharides (2 monosaccharides) and polysaccharides (long chains or monosaccharides)

132
Q

What enzymes break down disaccharides and polysaccharides!?

A

Carbohydrase enzymes

133
Q

What are disaccharides and polysaccharides broken down into!?

A

Monosaccharides (simple sugars)

134
Q

Where is the carbohydrase enzyme produced!?

A

In you mouth (saliva)
Pancreas
Small intestine

135
Q

What are proteins!?

A

They are large molecules from amino acids joined together to form chains

136
Q

What enzymes do proteins include!?

A

Haemoglobin
Collagen
Keratin

137
Q

What does each protein contain!?

A

Hundreds or even thousands of amino acids joined together in a unique sequence which are folded into the correct shape

Which gives each protein it’s own individual properties

138
Q

Protease is responsible for what!?

A

Breaking down proteins in our food into amino acids

139
Q

How are new proteins formed!?

A

By different enzymes joining amino acids together which are needed for growth and repair

140
Q

Where are protease enzymes produced!?

A

Stomach
Pancreas
Small intestine

141
Q

What are lipids!?

A

They are fats and oils

142
Q

What are lipids made from!?

A

They are large molecules made from smaller units of fatty acids and glycerol

143
Q

What breaks down lipids!? And how does it do it!?

A

Lipase

Breaks down lipids in the diet into fatty acids and glycerol

144
Q

Where is lipase produced!?

A

Pancreas
Small intestine

145
Q

What are all 3 enzymes also used for!?

A

Absorbing nutrients that we need from food in an exchange system. It does this by have a large surface area

146
Q

Where does digestion start!?

A

In your mouth

147
Q

What is the name of the organ that releases saliva!?

A

Salivary gland

148
Q

What enzyme does saliva contain!?

A

Amylase

149
Q

What is amylase used for in digestion!?

A

Helps break down carbohydrates

150
Q

What type of digestion occurs in the mouth!?

A

Chemical digestion

151
Q

What happens after our food is placed into our mouths!?

A

We bite our food with our teeth

152
Q

What does biting our food do to benefit digestion!?

A

Breaks down food into smaller pieces making it easier to swallow and it increases the surface area of food!

153
Q

What type of digestion is chewing!?

A

mechanical digestion

154
Q

What do chemical and mechanical digestion help with!?

A

Helps to move things along

155
Q

What is the 3rd step of digestion!?

A

After swallowing your food it travels down the oesophagus to the stomach

156
Q

What is the function of the oesophagus!?

A

Carries food from mouth to stomach

157
Q

Describe the stomach……

A

The stomach is a big,hollow, j-shaped organ, that’s got lots parts to break down food

158
Q

Describe the stomach wall…..

A

A strong muscular stomach that churns food

159
Q

Is the churning of food a chemical or mechanical digestion!?

A

Mechanical

160
Q

What enzyme does the stomach contain!?

A

Protease which breaks down proteins

This is chemical digestion

161
Q

What does the stomach also contain!? And what is it used for!?

A

Hydrochloric acid which is a strong acid and it is used to kill bacteria in food and lowers the pH of the environment which helps protease enzymes to work

This is chemical digestion

162
Q

What is the 4th stage of digestion!?

A

Food is passed through the small and large intestines

163
Q

What are the 2 sections of the small intestines called!?

A

The duodenum and the ileum

164
Q

Which part of the small intestine does food travel through first!?

A

The duodenum

165
Q

what happens in the duodenum during digestion!?

A

Lipids are digested and even some proteins and carbohydrates are digested here too!

166
Q

What occurs in the ileum during digestion!?

A

All the pieces of food are finally absorbed by the blood stream and taken to the rest of the body for energy, growth and repair

167
Q

What does the ileum contain!? And what do they do!?

A

Villi which increase surface area which allows a lot of absorption

168
Q

There are 3 adaptations of villi list the first one…….

A

The surface layer of the villus is only one cell thick meaning there is only a thin wall for food to travel through

169
Q

What is the 2nd adaptation of villi!?

A

They have a good blood supply from a network of blood vessels that helps carry absorbed food away from the

170
Q

What is the 3rd adaptation of villi!?

A

Each villus is covered in there own little villi called microvilli

171
Q

What is the 5th process of digestion!?

A

Your liver,pancreas and gall bladder then help out.

172
Q

What does the liver contain!?

A

Bile

173
Q

Where is bile stored!?

A

It is stored in the gall bladder and is then squirted into the small intestine

174
Q

What is bile used for!?

A

Used to neutralise the acidity in foods so that the digestive enzymes made in the pancreas can work this all occurs in the stomach

175
Q

What does bile also help with!?

A

Fat digestion. It makes the large fat globules smaller so that increases surface area for the enzymes to work on!

176
Q

What is the 6th process of digestion!?

A

Everything left in the small intestine carries on to the large intestine where water is absorbed and a process called egestion begins

177
Q

What is egestion!?

A

Taking food in

178
Q

What is the 7th process of digestion!?

A

Undigested food leaves the body as faecal matter through the rectum to the anus

179
Q

How do particles in a solid and a gas move!?

A

More continuously meaning that particles will spread themselves evenly throughout a liquid or gas

180
Q

Define the process diffusion……

A

If particles of a substance are in a higher concentration they will start to move from this region to where they are in a lower concentration

181
Q

What direction do particles move in during diffusion!?

A

They move in both directions BUT there will be a NET movement from a high to low concentration they will end up evenly spread throughout the liquid or gas but will continue to move!

182
Q

If a crystal of a coloured chemical is placed in water what will happen!?

A

The particles will diffuse and mix with the water particles creating an evenly concentrated solution

183
Q

State the steps of diffusion

A
  1. Coloured crystal is dissolved
  2. They mix through diffusion moving from high- low creating and evenly concentrated solution
184
Q

What is the word given to the crystal in this experiment!?

A

It is the solute
As it is being dissolved

185
Q

What is the word given to the water in this experiment!?

A

The water is the solvent

It dissolves the crystal

186
Q

Describe how the particles have moved during this experiment!? (Crystal and water)

A

The particles have moved from a HIGH concentration in the crystal to a LOW concentration in the water

187
Q

Describe a concentration gradient…..

A

The difference in concentration

188
Q

What causes the particles when they move DOWN a concentration gradient!?

A

A high concentration to a low concentration

189
Q

How else can diffusion occur!?

A

Across a membranes between the outside and the inside of cells

190
Q

How does a concentration gradient affect the rate of diffusion!?

A

The greater the difference in concentration the quicker the rate of diffusion

191
Q

How does temperature affect the rate of diffusion!?

A

The higher the temperature the more kinetic energy the particles will have so they will move and mix and a faster rate

192
Q

How does surface area of the cell membrane separating different regions affect the rate of diffusion!?

A

The greater the surface area the faster the rate of diffusion

193
Q

What is the name of the law that diffusion is calculated by!?

A

Fick’s law

194
Q

What is the calculation for diffusion!?

A

Rate of diffusion = surface area x concentration difference
——————————————————————-
Thickness of membrane

195
Q

How do substances diffuse in a single celled organism!? And what size will the substance need to be!?

A

In and out of the cell across its surface

Because of cell size substances will need to diffuse 1um OR less to where they are needed

196
Q

Explain how diffusion occurs multicellular organisms………. And name and example

A

1.Substances diffuse into the leaves and simple roots over their surface
2.Once inside the plant they don’t need to move far!
3.substances move into and around the plant by diffusion and osmosis
Eg: plants and moss

197
Q

Explain how diffusion occurs in simple organisms…….

A

1.They take in the substances over their body surface
2. Their needs are determined by their volume
3.all organisms at the same rate as their volume!!!!

198
Q

What is osmosis!?

A

The movement of water molecules across a selectively permeable membrane from a region of higher water concentration to a region of lower water concentration.

199
Q

What is osmosis in terms of concentration!?

A

Osmosis is the diffusion of water molecules from a region of higher concentration to a region where they are in lower concentration through a partially permeable membrane

200
Q

Does a dilute solution contain a high or low concentration of what’re molecules!?

A

High concentration of water molecules

201
Q

Does a concentrated solution contain a high or low concentration of water molecules!?

A

Low concentration

202
Q

What happens when the concentration of water is the same on both sides of the membrane!?

A

The movement of water molecules will be the same in both directions. There will be no NET movement of water molecules

203
Q

What happens with solutions containing different solutes in terms of osmosis!?

A

Similar observations will be made with solutions containing different solutes as what happened with a membrane

204
Q

What dilute solutions do cells contain!?

A

Dilute solutions of ions,sugars and amino acids

205
Q

What is an amino acid!?

A

The building blocks that make up a protein molecule.

206
Q

Describe the cell membrane of a living cell and how that affects osmosis….

A

The cell membrane is particularly permeable so water will move into and out of the cell by osmosis

207
Q

What is a root hair cell!?

A

A specialised cell that increases the surface area of the root epidermis to improve the uptake of water and minerals.

208
Q

Explain how an isolated plant cell placed in a dilute solution or water will take in water……

A
  1. Water will be taken in by osmosis
    2.if the soil is wet or moist then root hair cells will take up water by osmosis
209
Q

Explain how leaf cells of land plants do in terms of osmosis…..

A

Unless it is raining or humidity is high they have a tendency to lose water

210
Q

What is humidity!?

A

The amount of water vapour in the atmosphere measured as a percentage.

211
Q

What do plant cells contain outside the cell membrane!.

A

They have strong cellulose cell wall

212
Q

What is a cell membrane!?

A

A selectively permeable membrane surrounding the cell and controlling the entry and exit of materials.

213
Q

What is a cellulose!?

A

A carbohydrate. It forms the cell wall in plant cells

214
Q

Describe the cell wall……

A

The cell wall is fully permeable to all molecules. It supports the cell and stops it bursting when it gains water by osmosis

215
Q

Under normal circumstances cells in all organisms live in a safe equilibrium. Why is this!?

A

They have enough water to live but not too much. They also have the correct amount of salts and sugars

216
Q

What happens when we place a cell into pure water!?

A

In pure water, the cell contents push against the cell wall and the cell becomes turgid.

217
Q

What is a turgid!?

A

Enlarged and swollen with water. Having turgor. Description of a plant cell in which the vacuole has swollen due to water gain by osmosis.

218
Q

What is the role of a fully turgid cell!?

A

Fully turgid cells support the stems of non-woody plants.

219
Q

What happens when you place a cell in a more concentration solution!?

A

The cell membrance starts to pull away from the cell wall. The cell becomes flaccid.

220
Q

What is a flaccid!?

A

Soft and floppy.

221
Q

What happens when you put a cell into a highly concentrated solution!?

A

In a very concentrated solution, the cell membrane pulls away from the cell wall completely; this is plasmolysis.

222
Q

What happens to animal cells when they take in water by osmosis!?

A

Animal cells also take in and lose water by osmosis. They do not have a cell wall, so will change size and shape when put into solutions that are at a different concentration to the cell contents.

223
Q

What will happen to red blood cells in a concentrated solution!?

A

Red blood cells lose water and shrink in a concentrated solution.

224
Q

What happens to red blood cells if a solution is too dilute!?

A

They swell and burst in a solution that is too dilute.

225
Q

In an animal cell , what fluid’s concentration must be kept between strict limits !?

A

In animals, the concentration of body fluids, blood plasma and tissue fluid must be kept within strict limits.

226
Q

What happens if an animal cell loses or gains too much water!?

A

If cells lose or gain too much water by osmosis, they do not function efficiently.

227
Q

What is the equation for water uptake in 1 hour!?

A

Change in mass x 60mins/
length of experiment in minutes

228
Q

What is the equation for change in mass!?

A

Mass at end - mass at start/ mass at start x 100

229
Q

What is blood plasma!?

A

The liquid part of the blood containing useful things like glucose, amino acids, minerals, vitamins (nutrients) and hormones, as well as waste materials such as urea.

230
Q

What is tissue fluid!?

A

Fluid which is derived from blood plasma that passes through the walls of capillaries.

231
Q

How are substances moved down concentration gradients!?

A

Substances are transported passively down concentration gradients

232
Q

What is it meant by the term transported passively!?

A

This is the movement of molecules down a concentration gradient without the need for additional energy, eg diffusion and osmosis.

233
Q

How are substances often moved in terms of concentration!?

A

Often, substances have to be moved from a low to a high concentration against a concentration gradient.

234
Q

What is active transport!?

A

The transport of molecules against their concentration gradient from a region of low concentration to a region of high concentration. The process requires energy

235
Q

How does active transport allow plants to take up the nutrients they need from the soil around it!.

A

For plants to take up mineral ions, ions are moved into root hairs, where they are in a higher concentration than in the dilute solutions in the soil

236
Q

How are nitrates moved through the root hair cells!?

A

Nitrates are moved by the process of active transport from a low concentration in the soil to a higher concentration in the plant

237
Q

How is glucose molecules moved in animals!?

A

In animals, glucose molecules have to be moved across the gut wall into the blood.

238
Q

The glucose molecules in the intestine might be in a higher concentration than in the intestinal cells and blood – for instance, after a sugary meal. What does this mean!?

A

At this point it will diffuse from high concentration in the intestine to a lower concentration in the blood. This doesn’t require energy.

239
Q

there will be times when glucose concentration in the intestine might be lower. Meaning that!?

A

movement of glucose involves active transport. The process requires energy produced by respiration.

240
Q

What is aerobic respiration!?

A

Respiration that requires oxygen.

241
Q

What substances are transported by diffusion!?

A

Carbon dioxide, oxygen, water, food substances, wastes, eg urea

242
Q

Is energy required in diffusion!?

A

No

243
Q

What substances are transported by osmosis!?

A

Water

244
Q

Is energy required for osmosis!?

A

No

245
Q

What substances are transported by active transport!?

A

Mineral ions into plant roots. Glucose from the gut into intestinal cells, from where it moves into the blood

246
Q

Is energy required for active transport!?

A

Yes

247
Q

What is the cell wall made from?

A

cellulose

248
Q

How many flagella’s does a bacterial cell posses?

A

A bacterial cell can possess more than one flagella