Paper 2 Flashcards
(224 cards)
1
Q
What is the definition of homeostasis
A
The regulation of internal conditions to maintain a stable internal environment in response to changes in both the internal and external conditions
2
Q
Why do the conditions inside your body have to stay steady
A
As your cells need the right conditions in order to function properly
3
Q
What are the two control systems in your body called
A
Nervous system
Hormonal
4
Q
What are the three main components
A
Receptor
Coordination centre-brain and spinal cord
Effector-muscle or glands
5
Q
What is the CNS
A
Central nervous system- consists of the brain and spinal cord only.
6
Q
What is the function of a sensory neurone
A
The neurones carry information as electrical impulses from the receptors to the CNS
7
Q
What is the function of the motor neurone
A
The neurones that carry electrical impulses from the CNS to the effectors
8
Q
What do receptors do
A
Cells that detect stimuli
9
Q
What do effectors do
A
Respond to nervous impulses and bring about a change
Muscles contract
Glands secrete hormones
10
Q
What is a coordinate centre
A
Receives information from the receptors and the coordinates a response. The response is carried out by effectors
11
Q
What are synapses
A
The connection between neurones
12
Q
What are reflexes
A
Rapid and automatic responses to certain stimuli
They can reduce the chances of being injured
13
Q
What happens to your body if you get shocked
A
Your body releases the hormone adrenaline automatically
14
Q
What is a reflex arc
A
The passage of information in a reflex
15
Q
What happens when a source of pain is detected
A
When a stimulus is detected by receptors impulses are sent along sensory neurones to relay neurones in the CNS
16
Q
What happens when the impulses reach the synapse
A
They trigger chemicals to be released
These chemicals cause impulses to be sent along the relay neurone
17
Q
What us reaction time
A
The time taken to respond to a stimulus
18
Q
What can reaction rate be affected by
A
Age
Drugs
Gender
Tiredness
19
Q
What is the practical for reaction time
A
The person being tested should sit with their arm resting on the edge of the table
Hold a ruler vertically between their thumb and forefinger then let go with no warning
The person being tested should try catch the ruler as fast as they can
Reaction time is measured by the number on the ruler from where it’s caught
Repeat the test several times the drink caffeine and repeat again
20
Q
What are hormones
A
Chemical messengers sent in the blood
21
Q
Where are hormones produced
A
Endocrine glands
22
Q
What is the pituitary gland
A
The master gland
Produces many hormones that regulate body conditions
23
Q
What are ovaries
A
Produce oestrogen which is involved in the menstrual cycle
24
Q
What are testes
A
Produce testosterone which controls puberty and sperm production in males
25
What is a thyroid
Produces thyroxide which is involved in regulating things like the rate of metabolism heart rate and temperature
26
What is the adrenal gland
Produces adrenaline which is used to prepare the body for fight or flight response
27
What is the pancreas
Produces insulin which is used to regulate the blood glucose level
28
Features Of nerves
Very fast action
Act for a very short time
Act on a very precise area
29
Features of a hormone
Slower action
Act for a long time
Act in a more general way
30
What happens if blood glucose level is too high
Pancreas releases a hormone called Insulin
31
What happens if the blood glucose level is too low
Glycagen is released
32
What is diabetes
A condition that affects your ability to control you blood sugar levels
33
What is blood glucose monitored by
Pancreas
34
What is type 1 diabetes caused by
The pancreas failing to produce enough insulin
35
What does type 1 diabetes result in
Uncontrolled high blood glucose levels
36
What is type 1 diabetes treated with
Insulin injections
37
What is type 2 diabetes
Caused by the body no longer responds to insulin
38
What are risk factors for type 2 diabetes
High in fat diet
Lack of exercise
Obesity
39
What is type 2 diabetes treated
Carbohydrate controlled diet
Regular exercise
40
What are examples secondary sexual characteristics
Facial hair-men
Breast grow
41
What is the reproductive hormone in men
Testosterone
42
What is the reproductive hormone in women
Oestrogen
43
What happens at stage one of the menstrual cycle
Menstruation starts
The uterus lining breaks down for about 4 days
44
What happens at stage two of the menstrual cycle
The uterus lining build up again
From day 4 to 14
Ready to receive a fertilised egg
45
What happens at stage three if the menstrual cycle
An egg develops and is realeased From the ovary at day 14
Ovulation
46
What happens at stage four of the menstrual cycle
The wall is then maintained until day 28
47
What are the four hormones that control the menstrual cycle
FSH- follicle stimulating hormone
Oestrogen
LH- luteinising hormone
Progesterone
48
Where is oestrogen produced
Ovary
49
What does oestrogen cause
Uterus lining to go
50
What does oestrogen stimulate
the release of LH
51
What is FSH produced
Pituitary gland
52
What do FHS cause
Caused the egg to mature
53
What does FSH stimulate
The ovaries the produce oestrogen
54
Where is LH produced
Oestrogen
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What does LH Stimulate
The release of an egg at day 14
56
Where is progesterone produced
Ovaries
57
What does progesterone do
Maintains the lining of the uterus during the second half of the cycle
When levels of progesterone fails the lining breaks down
58
What does progesterone inhibit
The release of LH and FSH
59
What is an example of an oral contraceptive
The pill
60
What does the pill contain
Oestrogen and progesterone
61
How effective is the pill
Over 99% effective at preventing pregnancy
62
What are some side effects of the pill
Headaches
Nausea
Doesn’t protect against STIs
63
What is the contraceptive patch
A patch that sticks to the skin containing oestrogen and progesterone
Each patch lasts one week
64
What is the contraceptive Inplant
Inplant is Inserted under the skin of the arm
65
What does the implant do
Releases progesterone which stops the ovaries releasing eggs
An implant lasts up to three years
66
How long does the contraceptive injection last
2-3 months
67
What is an IUD
A device that is inserted into the uterus to kill sperm
68
What are non hormonal contraceptives used for
Designed to stop the sperm reaching the egg
69
What is an example of a non hormonal concentrative
A condom
70
What is a condom
Worm over the penis during intercourse to prevent the sperm entering the vagina
They protect against STIs
71
What is sterilisation
Involves cutting or tying the fallopian tube’s or the sperm duct in a male
72
What are the pros of IVF
It helps a lot of women get pregnant
73
Where are the adrenal glandse
Above the kidneys
74
What are the cons of IVF
Doesn’t always work
Can be expensive if do it to many times
Too many eggs could be stimulated
Success rate is low
Reaction due to hormones- vomiting abdominal pain
75
When is adrenaline released
In stressful of scary situations
76
What happens when your brain detects fear or stress
It sends a nervous signal to the adrenal glands which respond by secreting adrenaline
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What does adrenaline do
Increases heart rate
78
What are chromosomes
Really long molecules of DNA
79
What js DNA
The chemical that all the genetic material in a cell is made of
80
What does DNA contain
Coded information
Makes an organism work
81
What does your CNA determined
What inherited characteristics you have
82
What is DNA made of
DNA is a polymer
It’s made up of two strands coiled together in the shape of a double helix
83
What is a gene
A small section if DNA found in a chromosome
84
What do genes do
Codes for a particular sequence of different proteins
85
What is a genome
The entire set of genetic material in an organism
86
What do genomes allow
Scientists to identify genes in the genome that are linked to different types of disease.
87
Why is knowing what gene is linked to inherited diseases good
It can help us to understand them better and could help us develop effective treatments for them
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What is sexual reproduction
Where genes from two organisms are mixed
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What are gametes
Sex cells
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How are gametes produced
Meiosis
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What does each gamete contain
Half the number of chromosomes of a normal cell
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What happens when the egg and sperm cell meet
Forms a cell with the full number of chromosomes
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What does the offspring receive
A mixture of genes so inherits features from both parents
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What is asexual reproduction
One parent cell makes a new cell by dividing into two
No mixing of genes
No genetic variation
Each cell is genetically identical to the parent cell- called a clone
95
Where does meiosis happen
Reproductive organs
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What is the first step of meiosis
The parent cell has chromosomes in pairs
Half of the chromosomes have come from the organisms father and half from the mother
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What is the second step of meiosis
The DNA in the Laurent cell is copied
It makes an x-shaped chromosome
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What is the third step of meiosis
The cell divides
Each cell gets half of the chromosomes
99
What is the last step of meiosis
Each cell divides again
The x-shaped chromosomes are pulled apart
You end up with four new daughter cells theses are gametes
100
What does each gamete in a daughter cell have
Only has a single set if chromosomes
Is genetically different
101
How many pairs of chromosomes are in the body
23 pairs
102
What do the 23 pairs of chromosomes do
22 pairs are matched pairs
The 23rd pair are labelled X or Y- decide your sex
103
What chromosomes do males have
All males have an X and Y chromosome
The Y chromosomes causes male characteristics
104
What chromosomes do females have
All females have two X chromosomes
The XX combination causes female characteristics to develop
105
How many alleles do you have
2 alleles for every gene in your body
106
What happens if two alleles are the same
The organism is homozygous
107
What happens if the two alleles are different
The organism is heterogeneous
108
How do you know if a gene is dominant
Shown with a capital letter
109
How do you know if a gene is recessive
Shown with a lower case
110
What is a dominant allele
Expressed when present even when only one copy is present
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What is a recessive allele
Only expressed when there are two copies of it
112
What is the shape of DNA
Double helix
113
Define a gene
A small section of DNA on a chromosome
114
Define genotype
The DNA inherited that causes a characteristic
115
Define phenotype
A physical characteristics
116
Which allele causes cystic fibrosis
Recessive
117
What is polydactyly
Inherited disorder where a baby is born with an extra finger or toe
118
Give a symptom of cystic fibrosis
Sticky mucus in the lungs
Shortness of breath
119
What allele is polydactyly caused by
Dominant allele
120
How are embryos screened for inherited disorders
Before they put it into the mother
Scientists can remove a cell from each embryo and look at its genes
121
Why are people against embryo screening
Expensive
Unethical
122
Why do people like embryo screening
Can help stop people suffering
123
What can variation be
Environmental
Genetic
124
What is a mutation
A random change in an organisms DNA that can be inherited- gene is changed
125
What does mutation produce
Genetic variation
126
What effect does genetic variation have a a persons phenotype
Little to not
127
How can you avoid antibiotic resistant bacteria forming
Doctors should only prescribe if really needed
Should take the recommended amount that the doctors tell you
128
What is slowing down the release of new antibiotics
The rate if development is slow
The process is expensive
129
What is selective breading
When humans choose which plant or animals are going to bread
130
Why do people do selective breading
To get the desired characteristics
131
Examples of why people selective bread
For more meat or milk
Crops with disease resistance
Dogs with gentle personalities
132
What is the proces of selective breading
From your existing plants or animals select the ones which has the feature your after
Bread the together
Select the best from the offspring and bread them together
133
What are the disadvantages of selective breading
Reduces the number of different alleles in the population
Can be serious problems is a new disease spreads
134
What is genetic engineering
Changing an organisms DNA
135
What is genetic engineering used for
To give organisms new and useful characteristics
136
What does genetic engineering involve
Cutting a gene out of one organism and putting it into another organisms cells
Organisms that have the new gene inserted are called genetically modified organisms
137
How can genetic engineering be used in medicine
Bacteria can be genetically engineered to produce human insulin
This can be used to treat diabetes
138
What are some Concerns about genetic engineering
Most genetically modified embryos don’t survive
Some genetically modified animals suffer from health problems
139
What are fossils
The remains of plants and animals from thousands of years ago
They are found in rocks
140
What can fossils tell us
How much or how little organisms have changed over time
141
What are the three ways fossils form in rocks
From gradual replacement by minerals
From casts and impressions
From preservation in places where no decay happens
142
What is gradual replacement
Things like teeth, shells and bones don’t decay easy
This means they can last a long time when buried
When they do decay they get replaced by minerals
The minerals from the rock like substance shaped like the original hard part
143
What is casts and impressions
Fossils can be formed when an organism is buried in a soft mineral like clay
The clay hardens around it and the organism decays
The organism leaves a cast if it’s self
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What is preservation
Decay microbes only work if there is oxygen, moisture, warmth and the right pH
In some substances the conditions aren’t all present so decay doesn’t happen
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What is classification
Organising living organisms into groups
146
What is a habitat
The place where an organism lives
147
What is a population
All the organisms of one species in a habitat
148
What is a community
All the populations of different species in a habitat
149
What is an ecosystem
The interaction of a community or organisms with the non living parts if the environment
150
What do animals compete for
Food
Habitat
Water
Mates
151
What do plants compete for
Water
Sunlight
Light
Mineral ions
152
What do species depend on in a community
Food
Shelter
Pollination
Seed dispersal
153
What are abiotic factors
Non living things
154
Examples of abiotic factors
Light intensity
Temperature
Carbon dioxide levels
Oxygen levels
155
What is a biotic factor
Living things
156
Examples of biotic factors
New predator
New disease
Availability of food
Competition
157
What are adaptations
They allow the organism to survive
158
What are structural adaptations
Features if the organisms body structure
159
Examples of structural adaptations
Camouflage
Thick skin
Large ears
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What are behavioural adaptations
The ways that an organism behaves
161
Examples of behavioural adaptations
Migrating
162
What are functional adaptations
Internal process that helps an organism survive in the environment
163
What does extremophiles mean
They are adapted to live in extreme conditions
High temperature
164
What do food chains start with
Producer
165
What are producers
Make their own food using energy from the sun
166
Example of a producer
Green plants
Algae
167
What are consumers
Organisms that eat other organisms
168
What do primary consumers eat
Producers
169
What do secondary consumers eat
Primary consumers
170
What do tertiary consumers eat
Secondary consumers
171
What are predators
Consumers that hunt and kill other animals
172
How do you measure how many daisys are in a field
Place a quadrat on the ground in the first sample area- needs to be at random
Count all the daisys in the quadrat
Repeat the step as much as you can
Calculate the mean
173
How do you use a transect line
Mark out a line in the area you want to study using a take measure
Collect data alone the line by either- counting all the organisms your interested in that touch the line or by using quadrats.
174
What does the energy from the sun do to the water
Makes the water evaporate from the land and sea
Thus turns into water vapour
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What is precipitation
Fresh water for plants and animals
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Why do plants need water
Some water is absorbed by the soil
Plants take water up the roots
Plants need water for things like photosynthesis
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Why do animals needs water
For the chemical reaction in their bodies
They return water to the soil and atmosphere in their waste
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What is the first step to the carbon cycle
Plants take in carbon dioxide from the air during photosynthesis. They use carbon dioxide to make glucose
This glucose is used to make carbon compounds
They are used for growth
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What is the second step to the carbon cycle
Eating passes the carbon compounds in plants along to animals in the food chain
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What is the third step of the car in cycle
Both plant and animals respiration releases carbon dioxide back into the air
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What is the fourth step of the carbon cycle
Plants and animals eventually die or killed and turned back into useful products
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What is the fifth step of the carbon cycle
Burning plant. And animal products releases carbon dioxide back into the air
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What is the last step of the carbon cycle
Microorganisms break down animal waste and dead organisms
As they break down the material, they releases carbon dioxide back into the air through respiration
184
What is biodiversity
The variety of different species of organisms on earth or within an ecosystem
185
What can pollution affect
Water
Air
Land
186
How does pollution affect air
Smoke and acidic gases can pollute the air if they are released into the atmosphere
187
How does pollution affect Land
W use toxic chemicals for farming
We dump a lot of household waste in landfill
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How does pollution affect water
Sewage and toxic chemicals from industry can pollute lakes, rivers and oceans
Fertilisers used on land can be washed in water
Thus will effect the plants and animals that rely on water for survival
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Why should people be worried about global warming
Flooding
Changes in distribution of species
Less biodiversity
190
Why should people be worried about flooding
High temperature causes seawater to expand and ice to melt
Thus causes the sea level to rise
If it keeps rising there will be flooding
This will result in a loss of habitat
191
Why should people be worried about changes in distribution of species
Glob warming may lead to changes in rainfall and temperature
This could cause the spread of many animals and plant species to change
192
Why should people worry about less biodiversity
Some species may nit be able to survive in the climate
These species may become extinct
193
What do humans use land for
Things like building, farming, quarrying and dumping waste
194
What is deforestation
Cutting down the forest
195
What is deforestation done for
Clear land for farming
Grow crops
196
What does deforestation cause
Less carbon dioxide taken in
More carbon dioxide released
Less biodiversity
197
Why is less carbon dioxide take in bad - deforestation
Trees take in carbon dioxide
So cutting down trees means less carbon dioxide is removed from the atmosphere
198
Why is more carbon dioxide release bad - deforestation
Carbon dioxide is released when trees are burnt to clear land
199
Why is less biodiversity bad - deforestation
When forests are destroyed animals habitats will be destroyed
200
What are examples of minimising the damage to ecosystems
Breeding programs
Habitat protection
Reintroducing hedgerows and field margins
Recycling
Government programs
201
Why is breeding programms good for the environment
If an animal is endangered they can sometimes be released into the wild
This can boost the population or replace what’s being wiped out
202
Why is habitat protection good for the environment
Protecting and regenerating rare habitats helps to protect species that live in them
203
Why is reintroducing a hedgerows and fields margins good for the environment
Field margins are areas of land around the edges of fields where wild flowers grow
Hedges can be planted around fields to form hedgerows
Hedgerows and field margins provide a habitat for lots of types f organisms
204
Why is recycling good for the environment
This reduces the amount of waste that gets bumped in landfill sites
205
Why is government programmes good for the environment
Some governments have made rules to reduce deforestation
They have made to rules to reduce the amount of carbon dioxide released by businesses
206
Describe antibiotic resistance
Variation of population in the bacteria
Antibiotics kill most of the bacteria- not the bacteria resistant to the antibiotics
Bacteria that isn’t killed reproduces- antibiotics will no longer kill the bacteria
207
How can you stop antibiotic resistance
Finish the full course of antibiotics
Only take antibiotics for serious infections
Reduce the use of antibiotics
Simple hygiene
208
Describe genetic engineering
Remove target gene using enzymes
Insert the gene in a vector eg plasmids
Bacteria takes in the plasmid and reproduces
209
What are fossils
Remains if a dead organism that have been preserved
210
What is mineralisation
Hard parts of an organism are replaced by minerals
211
What is extinction
All the individuals species have died
212
What does endangered mean
Risk of extinction
213
What factors increase extinction
Pathogens
New predators
Natural disaster
Competition
214
Suggest why scientists are not certain what living ammonites looked like
Humans never saw the organisms
They only have the fossils to research from
215
Which scientist proposed the theory of natural selection
Charles Darwin
216
Describe the process of selective breading
Select organism with desired characteristics
Breed the organisms together
Repeat over generations
217
What is Carl Linneaus
Came up with a system of classifying organisms
Based on physical characteristics
218
What is the order of classification
Kingdom
Phylum
Class
Order
Family
Genus
Soecies
219
How did name living organisms
Binomial system
Genus species
220
Who is Carl Woese
Developed 3 domain system
Based on similar DNA
221
What is a domain
Bigger group than a kingdom
222
Describe the importance of a reflex action
Automatic
Fast to protect from harm
223
Describe the role of effectors in the nervous system
Glands- release hormones
Muscles- contract
224
