National 5 Course Flashcards
1
Q
What is a cell
A
A repeating unit of material that makes up an organism
2
Q
What is an organelle
A
The internal structures within a cell that carry out specific functions
3
Q
What is the function of a cell wall and in what types of cell is it found?
A
It supports, protects and maintains the shape of a cell
P + F + B
4
Q
What is the function of a mitochondria and in what types of cell is it found?
A
It is the site of aerobic respiration within the cell
P+ F + A
5
Q
What is the function of a cell membrane and in what types of cell is it found?
A
Controls the entry and exit of materials from a cell
P + F + B + A
6
Q
What is the function of a chloroplast and in what types of cell is it found?
A
It is the site of photosynthesis within a plant cell
7
Q
What is the function of a sap vacuole and in what types of cell is it found?
A
It stores the cells water and nutrients
P
8
Q
What is the function of a nucleus and in what types of cell is it found?
A
It’s controls the cells activities and stores genetic information
P + F + A
9
Q
What is the function of the ribosomes and in what types of cell is it found?
A
It is the site of protein synthesis within the cell
P + F + B + A
10
Q
What is the function of a plasmid and in what types of cell is it found?
A
It stores genetic information in bacterial cells only
11
Q
What is the function of the cytoplasm and in what types of cell is it found?
A
It is the site of all biochemical reaction within the cell
P + F + B + A
12
Q
What is a plant cell wall made of
A
Cellulose
13
Q
What is the structure of a cell membrane
A
A phospholipid bilayer
14
Q
What is a phospholipid bilayer
A
A double layer of phospholipids with protein placed randomly throughout, creating gaps for substances to pass in or out.
15
Q
What can cell membranes be described as
A
Selectively permeable
16
Q
What does selectively permeable mean
A
If a substance or membrane is selectively permeable, it only allows some substances to enter or exit the cell.
17
Q
What damages cell membranes and why
A
High temperatures as the proteins within the bilayer alter in shape, creating unnatural gaps in the membrane.
18
Q
What is passive transport
A
The movement of molecules down a concentration gradient, across a selectively permeable membrane, from an area of high to low concentration - requiring no energy
19
Q
What are two examples of passive transport
A
+ osmosis
+ diffusion
20
Q
What is osmosis
A
The movement of water down a concentration gradient from an area of high to low concentration - requiring no energy
21
Q
What effect does osmosis have on a plant cell
A
They either become plasmolysed or turgid
22
Q
What causes a plant cell to become turgid
A
When water travels into the cell from outside, causing it to swell and push the cell membrane out until it touches the cell wall.
23
Q
What causes a plant cell to become plasmolysed
A
When water exits the cell down a concentration gradient, causing the cell membrane to shrink away from the cell wall.
24
Q
What happens to an animal cell during osmosis
A
They either shrink or burst as they have no cell wall
25
What is active transport
The movement of molecules against a concentration gradient from an area of low to high concentration. This requires energy in the form of ATP, meaning cells which undergo active transport have a high number of mitochondria.
26
What is DNA
A molecule found in the nucleus of all living organisms (except bacteria), that stores their genetic information.
27
Where is DNA kept in a bacterial cell
In a ring like structure called a plasmid
28
What is the structure of DNA described as
A double stranded helix that consists of two sugar-phosphate backbones that curve around each other, held together by complementary base pairs.
29
What are DNA molecules contained in
Structures known as chromosomes
30
What are the four base pairs
+Adenine
+Thymine
+Guanine
+Cytosine
31
What is the pairing of the bases in a DNA strand
Adenine and Thymine
Guanine and Cytosine
32
What is a gene
A section of a chromosome that codes for a particular characteristic
33
What are the base pairings used to create and where does this process happen
The bases are used to synthesis proteins in the ribosomes
34
How does the base sequence determine the protein
A molecule of mRNA enters the cell and replicates a complementary copy of the base sequence of the DNA (as the DNA is too large to leave the nucleus). It then takes this copy to the ribosomes where the base sequence codes for a sequence of amino acids (3 bases= 1 amino acid) which join together to form a polypeptide chain. The way this chain folds then decides the type and function of protein that is formed.
35
What are five different types of protein
```
+ enzymes
+ hormones
+ antibodies
+ structural
+ receptors
```
36
What is an enzyme
A biological catalyst which is produced in all living cell which increases the rate of a biochemical reaction without being used up in the process.
37
What is a hormone
A chemical messenger that is transported in the blood
38
What is an antibody
A protein which provides defence against viruses and diseases by binding to them, allowing white blood cells to destroy them.
39
What is a structural protein
One which provides strength and support for cell structures
40
What is a receptor
A substance that allow cells to recognise specific chemical signals
41
What is the name of a substance that an enzymes reacts with
A substrate
42
What is the relationship between an enzyme and it’s substrate
They are complementary in shape, meaning that they bind together perfectly to form a singular product. For this reason, they are described as specific to one another as they are only complementary in shape to one particular substrate.
43
What is the area where an enzyme binds with its substrate known as
It’s active site
44
What are the two main types of enzyme reaction
- Synthesis
| - degradation
45
What is a synthesis reaction + example
When two or more substrates combine with an enzyme to form a singular product
E.g. G-1-P —phosphorylase—> starch
46
What is a degradation reaction + example
When one substrate is broken down into two or more products
e.g. HPCOW
47
What is an enzyme’s optimism pH or temperature
The range of values at which the enzyme activity is at its highest ( fastest rate of reaction)
48
What will occur when an enzyme is put in a temperature or pH that is either too high or outside of its range
It will become denatured, meaning it will drastically change in shape. This means that it will no longer be complementary to its substrate and can no longer react.
This is IRREVERSIBLE
49
What is genetic engineering
The artificial transfer of genetic information between cells
50
What are some uses of genetic engineering
To improve the genes of a particular species, increasing their chances of survival or improving an aspect of their life.
51
In what cell does genetic engineering usually occur
A bacterial cell
52
What is the sequence of genetic engineering
1: the require chromosome is extracted from its cell
2: the required gene is cut out of the chromosome using enzyme ‘scissors’
3: a plasmid is extracted from its host bacterial cell
4: a gene-sized section is cut out using enzyme ‘ scissors’
5: the required gene is placed in the plasmid and returned to the host bacterial cell and is produced and harvested in ideal conditions
53
What is an example of a use of genetic engineering
The production of human insulin to treat patients of type 1 diabetes
54
What is respiration
The process by which cells produce energy, by breaking down glucose
55
What is respiration controlled by
Enzymes
56
What is the word equation of respiration
Glucose + oxygen —> carbon dioxide + water + energy (in the form of ATP)
57
What is ATP formed from
ADP + Pi
58
What is ATP used for within the body
+ muscle cell contraction
+ cell division
+ active transport
59
What occurs when oxygen is present during respiration
Aerobic respiration
60
What occurs when oxygen isn’t present during respiration
Fermentation
61
What occurs during stage 1 of respiration
+ glucose is broken down into 2 molecules
+ 2 molecules of ATP are produced from 2 ADP + 2Pi
+ occurs in the cytoplasm
+ does not require oxygen
62
What occurs during stage 2 of (aerobic) respiration
+ 2 molecules of pyruvate is broken down into carbon dioxide and water
+ 36 molecules of ATP are formed from 36ADP + 36Pi
+ occurs in the mitochondria
+ requires oxygen
63
During fermentation, what occurs after stage 1
+Pyruvate is broken down into lactate in animals
+pyruvate is broken down into ethanol and CO2 in plants
+ 2 molecules of ATP are produced from 2ADP + 2Pi
64
What is the purpose of cell division
It allows them to produce new cells, in order to:
+ grow new cells
+ repair old cells
+ asexually reproduce (only unicellular organisms)
65
What is the chromosome complement
When a daughter cell has the exact same genetic information in its nucleus as the original mother cell.
66
What is the process by which animals make new body cells
Mitosis
67
Describe the process of mitosis
1: the chromosomes duplicate and bind with one another to form a chromatid, he,d together by a centromere
2: the nuclear membrane breaks down, allowing spindle fibres to enter the nucleus from opposite poles. While they do this the chromatids line up on the equator of the cell
3: the spindle fibres pull the chromatids apart, back into chromosomes, and take them to opposite poles of the cell
4: two nuclear membrane form, trapping each set of chromosomes at opposite poles
5: finally, the cytoplasm divides creating two new cells with identical genetic information, meaning the chromosome complement is maintained
68
What is a diploid cell
One which contains two sets of chromosomes, with a tootles of 46. All somatic (non-sex) body cells are diploid
69
What is a haploid cell
One which contains only one set of chromosomes, with a total of 23. These are gametes (sex cells)
70
What is a stem cell
An unspecialised cell, meaning it has not yet adapted to carry out a certain function.
71
What are the uses of stem cells
+ repair, damage and growth
| + specialisation
72
What are the two types of stem cells
- embryonic
| - tissue
73
What are embryonic stem cells
Completely undeveloped cells from an embryo that can develop and specialise into any cell in your body
74
What are tissue stem cells
Ones which come from animal tissue and can only specialise into cells which are of the same family as them. E.g. a blood tissue stem cell only has the ability to divide into other blood cells.
75
What is the structure of a red blood cell
+ bi-concave shape
| + no nucleus
76
What is the purpose of these adaptations to a red blood cell
+The bi-concave shape increases the cells goal surface area, allowing it to carry more haemoglobin which in turn carries and increased amount of oxygen
+ the lack of nucleus allows for more haemoglobin to be stored too
77
What is the organisation of: organs, tissues, organisms, cells and organ systems.
Cell —> tissue—> organ —> organ system —> organism
78
What is the CNS and what does it comprise of
CNS= Central Nervous System
It comprises of the brain, nerves and spinal cord
79
What is the purpose of the CNS
It processes information from the five sense and coordinates a bodily response.
80
What is a neuron
A specialised nerve cell which carries electrical nerve impulses along the CNS
81
What are the three main types of neuron
+ sensory
+ inter
+ motor
82
What is the purpose of the sensory neuron
The sensory neuron receives impulses from receptors, such as the eyes or ears, and carries them to the inter neuron.
83
What is the purpose of the inter neuron
The inter neuron configures and transmits impulses from the sensory neuron to the motor neuron.
Inter neuron = CNS
84
What is the purpose of the motor neuron
The motor neuron carries chemical impulses from the inter neuron to effectors, such as muscles
85
What is a reflex arc
A smaller scale example of the flow of information. It takes the same form as that of a regular FOI, however instead of travelling to the brain (inter), the impulses only travel to the spinal cord - increasing the reaction time.
86
What is the purpose of a reflex arc
To provide a instant reflex to an output that may endanger the body.
87
What is the gap between two neurons called
A synapse
88
How do impulses transmit over a synapse
As they reach the near edge of a synapse, they release a gas which diffuse across the gap and triggers an effector on the other side of the synapse. This results in the same impulse being carried.
89
What are the two animal gametes
+ sperm. MALE
| + egg (ova). FEMALE
90
Are gametes diploid or haploid
Haploid
91
Where are animal gametes produced
+ sperm are produced in the testes
| + eggs are produced in the ovaries
92
What are the plant gametes
+ pollen. MALE
| + ovule/ egg. FEMALE
93
What is fertilisation
The fusing of the nuclei of two opposing sex gametes. This occurs as they both require another set of chromosomes, due to the fact that their are haploid. As the nuclei fuse, they create a diploid zygote.
94
Where does fertilisation occur in an animal
In the females oviduct
95
What are the four main parts of the brain
+ cerebrum
+ cerebellum
+ medulla
+ endocrine gland
96
What is the function of the cerebrum and where is it located
Function: controls conscious though and memory
Found in the top section of the brain
97
What is the function of the cerebellum and where is it located
Function: controls balance and movement
Found at the bottom right of the brain
98
What is the function of the medulla and where is it located
Function: controls heart and breathing rate
Found in the central bottom area of the brain
99
What is the function of the endocrine gland and where is it located
Function: releases hormones into the bloodstream
Found in the boot, left section of the brain
100
What is a hormone
A chemical messenger that travel sont he bloodstream.
101
In what way are hormones alike to enzymes
They are complementary in shape and therefore specific to their substrate.
102
If your blood sugar is too HIGH what pigment does your pancreas release
Insulin
103
If your blood sugar is too LOW what pigment do your pancreas release
Glucagon
104
If your blood sugar is too HIGH what does your livery convert
GLUCOSE into GLYCOGEN
105
If your blood sugar is too LOW what does your liver convert
GLYCOGEN INTO GLUCOSE
106
What effect does type 1 diabetes have
Your body does not produce insulin
107
What effect does type 2 diabetes have
The body becomes resistant to insulin
108
What is variation
The difference in appearance or any other phenotype between individuals of the same species
109
What are the two main types of variation
+ discrete
| + continuous
110
What is discrete variation
When a characteristic can be categorised into a finite number of groups
e.g. blood type
111
What is continuous variation
When a characteristic can give na infinite number of different values
e.g. height or weight
112
What is a gene
A singular section of DNA that codes for a particular characteristic
113
What is the term used to describe a characteristic that is coded for by more than one gene
Polygenic
114
Is a polygenic characteristic and example,of discrete or continuous variation
Continuous
115
What is an organisms phenotype
It’s observable characteristic (exterior qualities)
These tend to be polygenic
116
What is an organisms genotype
The genetic information/ coding that decides the organisms phenotype
117
What is an allele
Separate forms of the same gene
118
What are the two types of allele
+ dominant
| + recessive
119
What is the dominant allele
The allele which displays its effects through the phenotype ( the allele that actually affects the organisms appearance)
120
What is the recessive allele
The allele which does not display its effects as they are masked by the dominant allele. This allele skips generations.
121
Does the dominant allele take a capital or lower case letter
Capital
122
Does the recessive allele take a capital or lower case letter
Lower case
123
What is an organism which consists of only the same alleles known as
Homozygous
124
What is an organism which contains two different alleles known as
Heterozygous
125
What is the predicted ratio of the F2 genotype
3 dominant:1 recessive
126
In a leaf cell, where is the stomata located
In the middle of the lower epidermis
127
What cells control the opening and closing of the stomata
Guard cells
128
What is the xylem and what is it composed of
The xylem is a cylindrical tissue that stems from the root of a plant, carrying water and nutrients up the stem and into the leaves
- composed of dead cells
- contains spirals of lignin which provide structural support
129
How does the water from the soil enter the xylem.
The water enters the root hair cells of the plant via osmosis, where it is then transported to the bottom of the xylem
130
What is the phloem and what is it composed of
The phloem is a cylindrical tube which carries sugars from the leaves to where they are required in the rest of the plant.
- composed of living cells
- contains porous sieves which prevent other substances from entering the rest of the plant, these sieves are controlled by neighbouring companion cells
131
What is the name of the process by which water is transported from the soil into the air, via the plant
Transpiration
132
What occurs during transpiration
1: water from the surrounding soil enters the root hair cells via osmosis
2: the water then enters the xylem and travels upward through the stem via active transport/ capillary action
3: the water then reaches the leaf and the spongy mesophyll, where it evaporates into the air by exiting through the stomata
133
What are the factors which affect the rate of transpiration
- wind speed
- humidity
- temperature
- surface area
134
What are the three cells that blood is made up of
+ red blood cells
+ white blood cells
+ plasma
135
What is the purpose of a red blood cell
Transport oxygen around the body via the blood stream.
136
What is the pigment that absorbs oxygen, found in a red blood cell + what is formed when it absorbs oxygen
Haemoglobin is the pigment and it forms oxyhemoglobin when it binds with the oxygen
137
How does oxygen enter the blood
Via diffusion as it diffuses from the lungs into the bloodstream
138
What are the two types of white blood cell
+ phagocytes
| + lymphocytes
139
How does a phagocyte destroy pathogens
They engulf and digest them, breaking them down into harmless molecules (phagocytosis)
140
How does a lymphocyte destroy pathogens
It produces antibodies which destroy their specific pathogen ( complementary in shape) by binding in to them and destroying it.
141
What is the name of the system by which blood is transported around the body
Circulatory
142
What is the circulatory system composed of
+ the heart
+ veins
+ Arteries
143
What is the direction of blood flow in the heart
Vena cava —>right atrium—>right ventricle—>pulmonary artery—>pulmonary vein—>left atrium—>left ventricle—>aorta
144
Where does the blood go as it exits the heart through the pulmonary artery
The lungs to be oxygenated
145
What part of the heart contains the deoxygenated blood
Right atrium + ventricle
146
What is the name of the hearts private supply of blood
The coronary arteries and veins
147
What is the purpose of the heart
To pump blood around the body
148
What are the three main type of blood vessel
+ veins
+ arteries
+ capillaries
149
Describe a vein and it’s function
Function: carries blood from around the body TO the heart
- thin walls (contains low pressure blood)
- wide central channel (reduces friction)
- contains valves (pump back and forward to prevent the blood from back flowing/washing)
150
Describe an artery and it’s function
Function: carries blood FROM the heart to the rest of the body
- thick walls (contain high pressure blood)
- thin central channel (increases friction)
- elastic (allows the vessel to expand and contract as the organism breaths)
151
Describe a capillary and it’s function
Function: exchange vessels that allow materials to diffuse between the blood and tissue
- thin walls (easy diffusion)
- many cells situated next to each others (increases surface, increasing rate of diffusion)
152
What is the large tube at the top of the lungs known as
The trachea
153
What are the two smaller cylinders that stem from the trachea known as
Bronchi
154
What are the many twig like branches that stem from the bronchi known as
Bronchioles
155
What are the small air sacs on the end of the bronchioles known as
Alveoli
156
What are the alveoli surrounded by that aids them in their functions
Function: they are the site of gas exchange in the lungs
Surrounded by a network of capillaries which allow easy diffusion
157
What happens as the gases diffuse in the alveoli
1: deoxygenated blood travels into the lungs via the capillaries
2: the oxygen diffuses from the alveoli into the capillaries, via diffusion, down a concentration grading
3: the carbon dioxide in the alveoli from the blood, via diffusion, down a concentration gradient
4: the carbon dioxide is then exhaled out of the lungs as a waste product
158
What is a villus
A small hair-like substance that lines the small intestine, absorbing nutrients and fat.
159
What are villi composed of
+ capillaries
| + a lacteal
160
What does the lacteal absorb
Fatty acids and glycerol
161
What do the capillaries absorb
Glucose and amino acids
162
Why does the structure of a villi allow for efficient nutrient absorption
+ thin walls
+ large amount of blood capillaries
+ many cells, creating a large surface area
163
What is the biodiversity of a region
The total variety of living organisms in a singular area
164
What are producers
Organisms which produce their own energy/food (usually plants)
165
What are consumers
Organism which obtain food or energy by consuming producers or other consumers
166
What is a herbivore
An organism which only eats plant material
167
What is a carnivore
An organism which only eats meat/ animal material
168
What is an omnivore
An organism which eats both plants and animals
169
What is a predator
An organism which hunts, kills and feeds on another organism
170
What is a prey
An organism which is hunted, killed and eaten by another organism
171
What is a habitat
The area in which an organism lives
172
What is a population
The total number of members of a singular species within a habitat
173
What is a community
The total number of living organisms within a habitat
174
What is a species
Organisms which can interbreed with one another to produce fertile offspring
175
What is a food chain
A diagram showing the linear feeding relationships between organisms
176
What is a food web
A group of interconnected food chains
177
What is an ecosystem
A physical habitat and all the living organisms within, as well as how they interact with one another
178
What is the term used to describe an organisms role within an ecosystem
It’s niche
179
What is competition
Conflict between organisms whom require the same, finite resources.
180
What are the two main types of competition
- interspecific
| - intraspecific
181
What is interspecific competition
Competition between organisms of different species
182
What is intraspecific competition
Competition between organisms of the same species
183
What are the two types of factor that affect the life of an organism
+ biotic
| + abiotic
184
What is a biotic factor + example
A factor which is linked to interactions with other living organism(a living factor)
e.g. predation, disease, grazing...
185
What is an abiotic factor + example
A factor which is non-living and associated with the surrounding environment
e.g. temperature, light intensity...
186
```
What is... measured with:
A= temperature
B= pH of soil
C= light intensity
D= soil moisture
```
```
A= thermometer/temperature probe
B= pH meter/universal indicator
C= light meter
D= moisture meter
```
187
What are two sampling techniques used to sample living organism
+ pitfall traps
| + quadrats
188
What is a pitfall trap
A small hole in the ground that is lined with a container, with alcohol at the bottom. Small invertebrates crawl in and become sedated by the alcohol, allowing them to be recorded and inspected. There is a small, elevated roof overhead with a gap large enough for the organisms to crawl in.
189
What is a quadrat
A square, teal grid that is random,y thrown on a sampling area, in order to count the total number of organisms in that area. The number of organisms in a singular square is counted and multiplied by the total number of squares to gain a representative average.
190
What could be a source of error when setting up a quadrat
They quadrat is not thrown randomly or enough times
191
What could be a source of error when setting up a pitfall trap
+ no roof is placed, allowing other organisms to eat the sedated invertebrates
+ no alcohol, allowing the invertebrates to crawl back out.
192
Hold up...
Let me get it started BB with tha robbins lookin all RETARDED
193
What is an indicator species
A species of organism which indicates the environmental quality of an area through its presence/absence.
194
What is the general word equation of photosynthesis
Carbon dioxide + water —light and chlorophyll-> glucose + oxygen
195
What is photosynthesis
The process employed by green plants to produce their own energy source. This ability to produce their own food means they are classified as producers
196
What is chlorophyll
The pigment found in the chloroplasts of a plant cell in which absorbs the light energy from the sun and converts it into chemical energy.
197
What is the name of the food produced by photosynthesis
Carbohydrates (contain carbon, hydrogen and oxygen)
198
What is the name of the first stage of photosynthesis
Light reactions
199
What occurs during stage 1
+ Light energy from the sun is trapped by the chlorophyll and converted into chemical energy
+ This chemical energy is then used to split water into hydrogen and oxygen
+ some of the chemical energy is used to produced ATP from ADP + Pi
+ The ATP and hydrogen are carried onto the next stage and the oxygen is expelled from the cell as a waste product.
200
What is the name of the second stage of photosynthesis
Carbon fixation
201
What occurs during stage 2
+ the hydrogen and ATP from the first stage are combined with carbon dioxide from the air to produce glucose/sugar
202
Where does photosynthesis occur in a plant cell
In the chloroplasts
203
What is photosynthesis controlled by
Enzymes
204
What are the factors which affect the rate of photosynthesis
+ availability/concentration of carbon dioxide
+ level/amount of light intensity
+ temperature
205
What are some uses of the glucose produced by photosynthesis
+ stored as starch
| + used in respiration
206
How can you measure the rate of photosynthesis
- rate of carbon dioxide uptake
| - rate of oxygen production
207
What do the arrows represent in a food chain/web
The direction of energy transfer
e.g. mouse —> eagle
208
What is the first organism in a food chain usually
A producer
209
What happens to the amount of energy passed on from organism to organism at each stage
It decreases as the organism loses energy at each stage as it expends most of the energy before being consumed
Only around 10% of the organism energy is passed on to its predator
210
What are some outputs of energy loss
+ movement
+ growth of organism
+ heat production
+ breaking down undigested materials
211
What is a decomposer
An organism (usually bacteria or fungi) which decomposes waste products and undigested materials to produce energy.
212
What is the name of each level of a pyramid of numbers or energy
A tertiary level
213
What is the length of each bar proportional to in a pyramid
The number of organisms or the amount of energy
214
What is a fertiliser
A substance that contains increased levels of nitrates, which is added to soil to increase the nutrient levels of crops and increase their total rate of growth and annual yield.
215
Why does nitrogen increase plant growth
As it is essential to the production of amino acids, meaning by increasing nitrate levels, the protein production rate increase.
216
What is a disadvantage of fertilisers
They often run off the fields and into a early water source causing leaching
217
What happens during leaching
1: fertilisers run into the water,source and increase nutrient levels, increasing algae bloom
2: this means that algae covers the surface of the water, preventing light energy from reaching the underwater plants.
3: this means they cannot photosynthesise and produce oxygen
4: this results in the marine life such as fish dying as they have no oxygen to consume and respirate with
218
What is a pesticide
A substance which ca; be sprayed onto plants to decrease their competition by killing weeds and predators.
219
```
What do...target
A: pesticides
B: herbicides
C: insecticides
D: fungicides
```
A: animals
B: weeds
C: insects
D: fungi
220
What is a disadvantage of using pesticides
They do not decompose and therefore build up in organism as they consume other organism which have consumed the pesticide. This is called bioaccumulation and results in the death of the highest consumers apps they have consumed the most animals, and the pesticide become toxic.
221
What is an example of bioaccumulation
DDT, which killed many heron
222
What is a GM crop
A genetically modified crop which can replace fertilisers and pesticides as: they are biodegradable, can be modified to be repulsive to predators and have the ability to grown in all weathers
223
What is a biological control
An organism which is introduced to an ecosystem to reduce the number of a pest organism (a natural predator).
e.g. ladybirds are introduced to ecosystems to decrease the greenfly population.
224
What is a mutation
A random change to the genetic material of an organism, forming new alleles in the genotype. This occurs during mitosis and takes place in the DNA
225
What are mutagenic agents + examples
Mutagenic agents are factors which increase the rate of mutation
e.g. exposure to radiation, chemical exposure...
226
Mutations are either:
- advantageous
- neutral
- disadvantageous
227
What is an advantageous mutation
An advantageous mutation gives the organism an advantage by improving their phenotype to best suit their habitat. When this occurs, the organism has an increased chance of surviving sudden changes in the environment and going on to reproduce, passing on the advantageous mutation.
228
What is a neutral mutation
One which has no effect on the organism
229
What is a disadvantageous mutation
One which gives the organism a disadvantage in their phenotype, increasing their chances of detach ad decreasing their chances of reproduction .
e.g. sickle cell mutation producing abnormal haemoglobin, meaning the body cannot carry enough oxygen in the blood to support itself
230
What does variation and mutation result in
Some organism being better adapted to their environment, resulting in an increased chance of reproduction
231
What is an environmental selection pressure
Factors which make some individuals better at surviving through sudden changes in the environment. Individuals which have the advantageous mutation which allows them to do this are described as the ‘fittest’ as in survival of the fittest.
232
How are new species formed
1: a population of a singular species is split up by an isolation barrier (mountains, rivers...), resulting in two independent sub-populations.
2: over time these two sub-populations mutate and natural selection occur smearing that only organism switch the new advantageous phenotype survive.
3: when returned to each other p, the two sub-populations are so different that they cannot interbreed with one another to produce fertile offspring, meaning two new species have been made.
233
What is an isolation barrier
An isolation barrier is a natural factor which sourate a population
234
An isolation barrier can be:
+ geographical (mountains,rivers,desert...)
+ behavioural (feeding patterns, different niches...)
+ ecological (temperature, humidity...)
235
What is the name of the process of making a new species
Speciation
236
Where does fermentation occur
In the cytoplasm
237
What is the reliability of an experiment
How reliable the results are
Can be increased through repeats or exterior input
238
What is the validity of an experiment
If the experiment has been carried out fairly
Increases with accuracy of measurements and results
239
How are root hair cells suited to osmosis
They have a large surface area
240
What are the products of fermentation in plant cells
Ethanol and carbon dioxide
241
What is the product of fermentation in animals cells
Lactate (lactic acid)
242
What is the name of the stalactite-like structure in a leaf structure
The palisade mesophyll
243
What is the name of the stalagmite-like structure in a leaf structure
Spongy mesophyll
244
What does chlorophyll do with light energy
ABSORB IT and convert it into chemical energy
245
What is the name given to an increase of algae
Algal bloom
246
What is the name of the valve on the left of a diagram of the heart
The vena cava
247
What is the name of the valve going from the right ventricle to the lungs
The pulmonary ARTERY
248
What is the name of the valve that returns blood to the left atrium from the lungs
The pulmonary VEIN
249
What is the name of the valve through which blood exits the heart
The aorta
250
COMMON MULTIPLE CHOICE QUESTION: Why is there the least energy at the highest level of a food pyramid
As energy is lost at each level
251
What is the name of the organelle that produces stem cells in plants
Meristems
252
Is the phloem lignifies
No (only the xylem contains lignin)
253
What is the equation for the full regeneration of ATP
ADP + Pi + energy —> ATP
254
What is the name of a pyramid which shows the number of organisms at each level
A pyramid of numbers
255
What genes can an organism pass on through reproduction
Only the ones it possesses
256
What causes variation in a population
Mutation
257
How many molecules of ATP are made in:
A: The first stage of aerobic respiration
B: the second stage of aerobic respiration
C: Aerobic respiration as a whole
D: fermentation
A: 2
B: 36
C: 38
D: 2
258
Where does aerobic respiration occur
In the mitochondria
259
What is the name of the top and bottom, thin layers of a leaf plant
The upper and lower epidermis
260
How do stem cells renew or grow
Through cell division
261
What do hormones bind to
Receptors
262
Which leaf cell organelle contains chloroplasts
The palisade mesophyll
263
Where does stage 1 of respiration occur
In the cytoplasm
264
What is the only source of new alleles in an ecosystem
Mutation
265
CONGRATULATIONS CALLUM!
YOUR’E DONE!!!
