Unit 2B - Enzymes and Genetics Flashcards
0
Q
What is the definition of a catalyst?
A
A substance which increases the speed of a reaction, without being changed or used up in the reaction
1
Q
What are enzymes?
A
Biological catalysts produced by living things
2
Q
What are enzymes made up of?
A
Proteins, which are made up from chains of amino acids
3
Q
Apart from catalysts what else do protein act as a structural component for?
A
Tissues, hormones and antibodies
4
Q
What do chemical reactions usually involve?
A
Things being split apart or joined together
5
Q
What shape are enzymes and why?
A
Enzymes each have a unique fit which only fits one substance, so it can only catalyse one reaction
6
Q
What’s the optimum temperature for enzymes?
A
37c
7
Q
What is the temperature that enzymes are denatured?
A
45c
8
Q
Why are enzymes denatured at 45c?
A
If they get too hit the bonds holding the enzyme together break and so it no longer has it special shape and won’t work any more
9
Q
What happens if the pH is too low or high?
A
The pH interferes with the bonds holding the enzyme together changing the shape
10
Q
What is the usual optimum pH for enzymes?
A
Neutral pH 7
11
Q
What enzyme works best at pH 2 and why?
A
Pepsin is a protease enzyme that breaks down protein n the stomach, it works best at pH 2 so it is well suited for the acidic conditions
12
Q
What do digestive enzymes do?
A
Break down big molecules into smaller ones
13
Q
What are examples of big molecules?
A
Starch, proteins and fats
14
Q
What are examples of much smaller molecules?
A
Sugar, amino acids, glycerol and fatty acids
15
Q
Why are bigger molecules broken down?
A
So they can pass through the walls of the digestive system
16
Q
What converts starch into sugars?
A
Amylase
17
Q
What does protease convert proteins into?
A
Amino acids
18
Q
What does lipase convert lipid into?
A
Glycerol and fatty acids
19
Q
What are lipids?
A
Fats and oils
20
Q
Where is amylase made?
A
Salivary glands, pancreas,and the small intestine
21
Q
Where is protease made?
A
Stomach, pancreas and the small intestine
22
Q
Where are lipase made?
A
Pancreas and the small intestine
23
Q
What does bile do?
A
Neutralises stomach acids and emulsifiers fats
24
Where is bile produced made, stored and released into?
Made in the liver, stored in the gall bladder and released into the small intestine
25
Why does bile neutralise stomach acid?
Hydrochloric acid in the stomach too acidic for enzymes in the small intestine to work
26
Why does bile emulsify fat?
It breaks down the fat into tiny droplets giving it a much larger surface area for the lipase to work on, making digestion faster
27
Why is there Hydrochloric acid in the stomach?
To kill bacteria, and to give the right pH foe the protease enzyme pepsin
28
What happens in the small and large intestine?
Small - absorbs food from the digestive system into the blood
Large - removes excess water from the food
29
What is the definition of respiration?
Respiration is the process of releasing energy from glucose, which goes in in every cell
30
What is the name of respiration that needs plenty of oxygen?
Aerobic respiration
31
How often and where does aerobic respiration happen?
All the time in plants and animals, most reactions happen in the mitochondria
32
What is the word equation for aerobic respiration?
Glucose + oxygen ----------> carbon dioxide + water + energy
33
What are four examples that energy is used for?
Building larger molecules from smaller ones (protein form amino acids)
Allow muscles to contract so animals can move
In mammals and birds it is used to keep the body temperature constant
In plants, to build nitrates sugar and other nutrients into amino acids which are then built into proteins
34
Exercises increases?
Heart rate
35
How do muscles use oxygen?
They use oxygen to release energy from glucose, which is used to contract muscles
36
An increase in muscles activity requires and what does it cause to the blood?
More glucose and oxygen to be supplied to the muscle cells and more carbon dioxide to be removed from the muscle cells. So your blood flows at a faster rate to do this.
37
Physical activity increases the speed at which the heart pumps and ?
Increased breathing rate, and you breath more deeply to meet the demand of oxygen
38
Some glucose from food is stored as?
Glycogen
39
Where is glycogen mainly stored?
In the liver, but each muscle has its own store too
40
During vigorous exercise what happens to glycogen?
The stored glycogen is converted back into glucose to provide more oxygen
41
What type of respiration is used if there's not enough oxygen?
Anaerobic
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Why does anaerobic respiration happen?
If you do vigorous exercise your body can't supply enough oxygen to your muscles and so you start doing anaerobic respiration. It's the I complete breakdown of glucose which produces lactic acid
43
What are three bad things about anaerobic respiration?
The build up of lactic acid is painful, causes muscle fatigue (tired muscles - don't contract efficiently) and it doesn't release as much energy as aerobic respiration.
44
What is an advantage of anaerobic respiration?
You can keep using your muscles for longer
45
What's the word equation for anaerobic respiration?
Glucose --------> energy + lactic acid
46
After anaerobic respiration you'll have?
Oxygen debt
47
What is oxygen debt?
You have to repay the oxygen that you didn't get to your muscles in time, which means you breath harder for a while after you stop to get more oxygen in the blood
48
How is lactic acid removed from the muscles?
It is oxidised into harmless CO2 and water
49
Enzymes as used in?
Industry, to change food and as a biological detergent
50
What enzyme is used in biological detergent?
Protease and lipase
51
Why are protease and lipase used as biological detergents ?
Protease is a protein digesting enzyme, lipase is a fat digesting enzyme and so they are good at breaking down plant and animal matter and are ideal for removing stains like food and blood.
52
Why are biological detergents better than other detergents ?
They work at lower temperature (30c) saving energy costs
53
How are enzymes used in baby foods?
Proteins in baby food are pre digested using protein digesting enzymes (proteases) which makes it easier for the baby to eat
54
What enzymes turns starch syrup into sugar syrup?
Carbohydrate digesting enzymes called carbohydrases
55
How are enzymes useful in slimming foods and drinks?
The isomerase enzyme can turn glucose syrup into fructose syrup, as fructose is sweeter you can use less of it
56
What do enzymes do to the reaction?
Speed it up
57
What are four advantages of using enzymes in industry?
They only catalyse the reaction you want, as you don't need high temperatures or pressures it means you use less energy saving costs, work for a long time only one initial cost and they are biodegrade and cause less environmental pollution
58
What re four disadvantages of using enzymes in industry?
Some people allergic to enzymes, denatured by a small increase in temperatures and pH changes, expensive and contamination of enzymes can affect reactions
59
Chromosomes are really long molecules of?
DNA
60
What does DNA stand for?
deoxyribonucleic acid
61
Where is DNA found and what does it contain?
In the nucleus all the instructions to put an organism together and make it work
62
A section of DNA is called?
A gene
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Genes contain instructions to make?
Specific protein
64
How do cells make proteins?
By stringing amino acids together in particular order
65
How many amino acids are used and how many proteins do they make?
Only 20 amino acids are used yet they make thousands of different proteins
66
What do genes and DNA determine?
DNA determine what protein the cell makes e.g haemoglobin, and genes determine what order to put the amino acids in to make this protein. The proteins determine what type of cell it is e.g. Red blood cell
67
Is everyone's DNA the same?
No they are all unique
68
Everyone has unique DNA but?
Identical twins and clones
69
How does DNA finger printing work?
By cutting up someone's DNA into small sections and then separating them to give a unique pattern to tell people apart
70
What two things are DNA fingerprinting used for?
Forensic science and Paternity Testing
71
Why do people want a national genetic database?
If there was a crime you get check everyone in the country to see who it was
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Why are people against a national genetic database?
Invasion if privacy, who else could get there hands in it, errors can be made
73
What is mitosis ?
Mitosis is when a cell reproduces itself by splitting to form two Identical offspring
74
What is meiosis?
Meiosis produces cells which have half the normal number of chromosomes
75
What cell division makes cells for growth and repair?
Mitosis
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How many chromosome to normal body cells have?
23 pairs of chromosome, one from the farther one from the mother
77
If a body cell divided are the new cells different to the original cell?
No they are identical
78
Asexual reproduction uses which cell devision?
Mitosis
79
What are sex cells called?
Gametes
80
How many chromosome do gametes have ?
Half the usual number so 23 each
81
Why do gametes only have one copy of each chromosome?
So that when two gametes combine the fertilised egg will end up with the right number of chromosomes
82
Where does meiosis happen in humans?
Only in the reproductive organs (ovaries and testes)
83
How many division does meiosis involve?
Two
84
Describe the process of mitosis?
If a cell gets a signal to divide, it duplicates it's DNA so there is one copy for each new cell. The new copied DNA forms X shaped chromosomes, the left arm is identical to the right. The chromosomes line at the centre of the cell and the cell fibres pull them apart, the two arms go to opposite ends of the cell. Membranes form around each new set of chromosomes, these become the new nuclei of the two new cells. Lastly the cytoplasm divided leaving two identical cells.
85
In Meiosis what happens after the first division?
In the second division the chromosomes lien up again in the centre if the cell and the pair of chromosomes are pulled apart and you hey four gamete each with only 23 chromosome
86
What type of cell can turn into any type of cell?
Embryonic stem cells
87
What is the process called by which a cell changes to become specialised?
Differentiation
88
Where are stem cells found that can turn into any type of cell?
Early human embryos
89
Where are stem cells found in adult?
Bone marrow
90
Stem cells can be used to cure?
Many diseases
91
How are stems cells used to treat blood disease?
Stem cells can turn into new blood cells and replace the fault ones
92
How to scientists control differentiation of stem cells?
Changing the environment they're growing in
93
Why are some people against stem cell reasesrch?
They feel like human embryos shouldn't be experimented on as each one is a potential human life
94
Why do some people think stem cell research is good although using embryos to test?
Curing patients who already exist and suffering is more important than the right of embryos, the embryos experimented on are usually unwanted ones from fertility clinic that would otherwise be sets round
95
In the UK stem cell research has to follow?
Strict guidelines
96
What are the chromosomes labelled than decide whether you are a male and female?
XX and XY
97
If you are a women your 23rd pair of chromosomes is XX, what is it is you are a male?
XY (y chromosomes causes male characteristics ?
98
What type of chromosomes do sperm have that control the gender of the baby?
After the division in meiosis thee is a 50% chance each sperm cell gets an X chromosome and 50% it gets a Y chromosome.
99
What chromosomes do eggs have that control the baby's gender?
After the first division the two X chromosomes are split so each egg cell has one X chromosome
100
To find the probability of getting a boy or a girl you can draw a?
Genetic diagram
101
Who did genetic experiments with pea plant?
Mendal
102
What was Mendals three conclusions?
Characteristics are determines by hereditary units, hereditary units are passed on one unit from each parent and hereditary units can be dominant or recessive
103
What are hereditary units also known as?
Genes
104
What experiment did Mendal do?
He crossed pea plants of two heights to see the variation in the offspring
105
What are alleles?
Different versions of the same gene
106
I'm genetic diagrams what are alleles represented by?
Letters
107
If an organism has two alleles for a particular gene that are the same it is called?
Homozygous
108
If an organism has two alleles for a particular gene that are different what is it called?
Heterozygous
109
If two alleles are different, only one characteristic is present, what is the name of the allele for the shown characteristic?
Dominant
110
How can a organism show a recessive characteristic?
Both allele must be recessive
111
How can an organism show a dominant characteristic ?
It has to have either one dominant allele or two dominant alleles
112
What type of letters represent dominant and recessive alleles?
Dominant - capital letter
| Recessive - lower case letter
113
How many alleles do gametes have?
One
114
What are two genetic disorders?
Cystic fibrosis and polydactyly
115
What genetic disorder is called by a recessive allele?
Cystic fibrosis
116
What genetic allele is caused by a dominant allele?
Polydactyly
117
What is cystic fibrosis?
A genetic disorder of the cell membranes which results in the body producing a thick sticky mucus in the air passages and the pancreas
118
What is polydactyly?
A genetic disorder where a baby is born with extra fingers or toes
119
If you have one allele that causes cystic fibrosis you are a?
Carrier
120
Why do carriers not have cystic fibrosis?
As they only have one copy of the affected recessive allele the other allele will be dominant meaning they present no symptoms of cystic fibrosis
121
What do the alleles have to be like for a child to have cystic fibrosis?
They have to have to one the affected recessive allele which means both parents have to be with carriers of sufferers
122
To be a sufferer of polydactyly your parents have to be?
Only one parent has to be a sufferer and carry the affected dominant allele
123
How can you tell if embryos have genetic disorders?
Be screening them
124
How does the screening of embryos work?
During IVF a cell can be removed from the embryos allowing you to analyse it genes so you an see if it has any genetic disorders and only embryos with good alleles are implanted
125
What four reasons are there against embryonic screening?
People will end ou wanted to screen embryos so they can have the most desirable one, rejected embryos are destroyed, implies people with genetic disorders are undesirable (prejudice ) and screening is expensive
126
What four reasons are for embryonic screening?
Helps people stop suffering, laws stopping it going too far, during IVF most embryos are destroyed anyways, treating disorders costs the government money
127
Screening shouldn't be used for disorders that don't affect people s ?
Health
128
What are fossils?
Remains of organisms from many years ago, which are found in rocks
129
What are the three ways that fossils are formed?
From gradual replacement by minerals, from casts and impressions and from preservation in a place where no decay happens
130
How does gradual replacement by minerals work?
Things like, bones and shells don't decay easily and so last a long time, but when they do they are gradually replaced by minerals when they decay forming a rock like substance, the surrounding sediments turn to rock too but you can tell the fossil and rock apart
131
What are casts and impressions. ?
When fossils are buried in a soft material like clay, the clay later hardens around it as the organism decays, leaving a cast of its self
132
What fossils are found as casts and impressions ?
Animal burrows and plant roots
133
How does preservation happen?
In amber and tar pits there's no oxygen or moisture so decay microbes can't survive. Glaciers it's too cold and peat bogs are too acidic
134
What are two hypotheses of how life began on earth?
First life forms came into existence in primordial swamps or under the sea on earth. Or maybe simple organic molecules came from comets and this is life forms evolved from
135
Why does extinction happen?
If you can't evolve quickly enough
136
What are the six reasons that species become extinct ?
Environment changes too quickly, new predator kills them all, new diseases kill them all, they can't compete with other a species for food, a catastrophic event happens or a new species develops
137
What is speciation?
The development of a new species
138
What is a species ?
A group of similar organism that can reproduce to give fertile offspring
139
Why does speciation occur?
When populations of the same species become so different that they can no longer breed together to produce fertile offspring
140
What two things lead to speciation?
Isolation and natural selection
