Studied by 131 people
Correct this: asexual reproduction only requires one parent
Asexual reproduction only requires one parent CELL
Give the full answer: what will a build up of cholesterol in an artery leading to the leg do to muscle cells in the leg?
Less oxygen and glucose will reach the muscle cells
So they will carry out less aerobic respiration.
They will carry out more anaerobic respiration
And will release less energy.
The anaerobic respiration will also cause a build-up of lactic acid, which will lower the pH of the cells
Causing enzymes to denature
So the muscle cells will DIE.
Roles of oestrogen
Inhibits FSH
Stimulates LH
Is responsible for the development of secondary sexual characteristics
Thickens the uterus lining
Evaluating a conclusion: what if they don’t give information on the types of people tested on
We do not know if they tested on people of the same age/sex/mass (and some things specific to the condition - e.g. CHD and smoking or exercise) etc., so the results could be unreliable.
Function of the umbilical cord
Connects the foetus to the placenta. It contains the umbilical artery (carrying blood containing carbon dioxide and urea out from the foetus) and the umbilical vein (carrying blood containing oxygen, glucose, amino acids, vitamins, minerals and antibodies into the foetus).
Why do seeds need a food store?
To provide glucose, for respiration, as they cannot photosynthesise to make this glucose, as they do not have any leaves.
4 factors required for germination and reasons
Water - to activate enzymes
Oxygen - for aerobic respiration
Warmth - to provide the optimum temperature for enzymes
Light - to activate plant growth regulators
Phrase better: placenta allows for carbon dioxide and urea to pass from foetal to maternal blood
The placenta allows for carbon dioxide and urea to be removed from foetal blood, as it diffuses into maternal blood
What passes from maternal to foetal blood
Oxygen
Glucose
Amino acids
Vitamins
Minerals
Antibodies
Improve: results are reliable if the experiment has been repeated many times …
AND THE RESULTS ARE SIMILAR
Why count heart rate over 15s, not a minute?
There is less chance of losing count
It is quicker to collect results
The results of [whatever you are testing] may wear off quickly
When comparing results (3 marks)
Compare overall - e.g. both increase/decrease
Compare more specifically - e.g. smaller/greater increase/decrease
Bring in data - useful to state the (approximate) multiple that the final value is of the first in one date set, then compare this multiple with the multiple for the other data set
In disease terms, what does a vector do
Transfers the pathogen from organism to organism
If there is a lack of circulation to a particular area (it may go blue), what does this mean in terms of blood vessels
VASOCONSTRICTON occurs: the narrowing of blood vessels. This means less blood, and therefore less oxygen, reaches that area
How does less transpiration affect a plant
MINERAL IONS are not transported to the requiring parts of the plant. The plant will have less nitrates, to produce amino acids, for proteins, for growth; less phosphates, which are needed for the production of ATP and nucleotides for DNA; less magnesium for chlorophyll (and less potassium to regulate osmosis)
Benedict’s reagent in a low concentration of glucose
Orange / yellow-green
Correct this: different amino acids in a protein lead to the formation of a different protein
Different amino acids in a protein lead to the formation of a protein with A DIFFERENT SHAPE
Why is meat that is low in fat healthy
There is less chance of coronary heart disease, as there is less chance of arteries being blocked by plaque, containing cholesterol.
If it is low in fat, it’s probably high in protein - this means that when it is digested, the body has more amino acids for growth and repair.
Mineral ions for bones
Calcium, PHOSPHATES
What is meant by the term “selective breeding”
When HUMANS breed organisms that have desired characteristics together
Menstrual hormone graph
LH and FSH have similar shapes, but LH is taller. Progesterone is high towards the end of the cycle, and oestrogen has the first major rise.
How do abnormal sperm affect the chances of fertilisation
Abnormal sperm may not be able to swim to the egg, to fertilise it, which would reduce chances of fertilisation.
Respiration experiment with locusts - control variables
Same age, sex, species of locusts
Same mass (more cells = more respiration)
Temperature
Size of flask (space to move)
Time
Volume and concentration of KOH
Why are fruits healthy
They contain vitamin C to prevent scurvy, and fibre to aid peristalsis
Word better: a better supply of oxygen means that the oxygen debt is repaid quicker
A better supply of oxygen means that there is better removal of lactic acid (so a person can run for longer)
Why does the aorta have a thicker wall than the capillary
Aorta wall contains muscle and elastic tissue
As it carries high pressure blood from the LEFT VENTRICLE
Aorta needs to expand to carry this blood
Needs to transport more blood than the capillary
Two structures in bacteria that contain DNA
Plasmid and CHROMOSOME
To test a leaf for starch
Place the leaf in boiling water for 30 seconds, to kill and preserve it, then place in boiling ethanol, to remove the chlorophyll - use a water bath for this, as it is unsafe to heat using a Bunsen burner as ethanol is highly flammable. Rinse the leaf with water to soften and rehydrate it, pat dry, then test it using iodine solution - if the iodine changes colour from orange-brown to blue black, starch is present.
How to measure the area of the green part of a variegated leaf
Trace around the leaf, then trace around the green part, using tracing paper. Put the tracing paper onto squared paper and count the number of squares. Do this for both sides of the leaf.
Why is the mean maximum lung volume for males and females similar at age 7, but different at age 25
At age 25, the males’ mean maximum lung value is greater than the females, as males grow more than females. There is a greater difference from puberty, as males continue to grow between the ages of 16-25.
Advantages of using artificial insemination in selective breeding (in cows, for example)
Quicker and cheaper to transport semen than bulls
Can impregnate the cows after the bull has died
Can impregnate many cows
Safer for cows
Can you say that osmosis requires a concentration gradient
YES!!
How do viruses differ from living organisms
They are only able to reproduce inside living cells
They have a protein coat
They contain only one type of nucleic acid
They are smaller than all living organisms
They have no organelles (e.g. mitochondria)
They have no cytoplasm
They do not move
They do not respire
They have no sensitivity
They do not grow
They do not excrete
Why would the population of mice be higher in one year compared to others
More food
Due to warmer weather
Fewer predators
Less disease
Higher birth rate
Why would an owl population be fairly constant for a number of years
The birth rate was roughly equal to the death rate
Owls have no predators
They produce few offspring
There is not enough food to maintain a higher population of owls
Why might e-cigarettes be less harmful than normal cigarettes
There is less tar in e-cigarettes so there is less paralysis of cilia - this can cause chronic bronchitis
There are fewer carcinogens
There is less carbon monoxide in e-cigarettes
There is less risk of heart disease
It is easier to control nicotine levels
Apart from being addictive, why is nicotine a problem
It can increase risk of blood clots (and high blood pressure)
How could a scientist distinguish between conditions caused by polygenic or monohybrid inheritance in rats
If the condition shows continuous variation, it is polygenic
If it shows discontinuous variation, it is monohybrid
If it is monohybrid the offspring will show a simple pattern - you can see this by looking at pedigree diagrams
Why would you wait until a bull is 4 years old to start collecting its semen
So that it has undergone puberty, and will be producing sperm
Uses of water in plants
Reactant of photosynthesis
Keeps plant cells turgid
Transports mineral ions
Water is needed for cooling
Correct this: impossible
IMPROBABLE
Hepatic portal vein
Transports blood containing digested food (glucose, amino acids, and fatty acids and glycerol) from the small intestine to the liver
Factors that increase the risk of coronary heart disease
Diet containing too much saturated fat
Obesity (carrying extra weight puts a strain on the heart)
Lack of exercise
Genetics
Smoking
High blood pressure (damages arteries because the force of blood against artery walls increases)
What are the effects of smoking on the lungs
Tar paralyses cilia
This leads to a build-up of mucus in the trachea
Which can lead to a bacterial infection
Which can lead to inflammation of the airways
WHICH CAN LEAD TO COPD OR BRONCHITIS
Chemicals in tar also cause emphysema
Carcinogens in smoke cause lung cancer
Advantages of biological control
No need to reapply
Specific to the pest species
No risk of resistance
No bioaccumulation
Lasts longer than pesticides
Correct this: measure the mass of plants
Weigh plants (using a mass balance)
How does having genetic variation in a population help it combat disease?
Mutations in DNA lead to different alleles forming. Some of these alleles give the organisms resistance to pathogens, which means that they will survive if the pathogen infects the population.
Respiring seeds experiment: why is cotton wool used at the mouth of the flask
To allow carbon dioxide to exit the flask, and oxygen to enter
Function of the digestive enzymes in the head of the sperm
Penetrates the membrane of the egg
Function of the nucleus of the sperm
Contains DNA - 23 chromosomes, to fuse with the nucleus of the egg to form a diploid nucleus
Imagine a calorimetry experiment with glucose. There is a waste tube for the products (going through the water in the calorimeter). Why is it coiled?
To increase the surface area, so that there is better transfer of heat to the water
For sewage etc dumped into a river, when talking about bacteria: not only do they decompose the sewage, using oxygen for aerobic respiration, but…
…the population of bacteria grows, so there are more bacteria, so they carry out more decomposition, and use up more oxygen for aerobic respiration.
All the ways in which the net can protect fish in a fish farm
Protects them from predators in the sea, from predatory birds, it keeps out other fish which could cause competition and spread disease
Causes of emphysema
Smoking, dust, fumes, genetics, bronchitis
Describe how fungi decompose organic material
Fungi are saprotrophs: they secrete enzymes that carry out extracellular digestion, from their hyphae, onto the organic material, and absorb the products of the digestion. These may include small, useful molecules such as water and carbon dioxide.
ALL the effects of increased carbon dioxide in the atmosphere
Enhanced greenhouse effect
Melting of ice caps
Destruction of habitats
Migration of species, including pests, and disease-carrying organisms
Extinction of species, leading to disruption of food chains and webs
Extreme weather events
Abiotic factor for plant growth - not light intensity, but:
SUNLIGHT
Biomass
The total mass of living organisms, measured in a specific area over a set time period
Why does an increased rate of photosynthesis not necessarily result in an increase of the same rate in biomass produced
Not all of the glucose produced in photosynthesis is stored in the plant (as starch or sucrose) which increases biomass, or used for growth. Some is used in respiration, to release energy for metabolic processes such as active transport.
Why might we want plants (not just to look pretty)
As a source of food, to release oxygen, and to absorb carbon dioxide
Method for observing pollen grains
Use a microscope. Place the pollen grains on a microscope slide, stain them with a dye, and place a coverslip over the slide (to prevent the samples from drying out).
Importance of cell differentiation
This allows stem cells to become specialised cells, so that they can form tissues and organs (e.g. the heart)
Reaction of roots to light
They show negative phototropism - they grow away from the light
Size difference between RBCs and WBCs
RBCs are smaller
Factor relating to the particles themselves (that cannot be changed) that affects rate of diffusion
Size - smaller particles will diffuse faster
What can diffusion do that active transport cannot
Diffusion can take place in non-living systems
Why might a strawberry field need more fungicide than a cereal field
Fruits are more prone to saprotrophic decay
Why are antibodies in milk useful for babies
They prevent infection by specific pathogens and provide immunity.
The uses of lipid
Insulation or protection around organs
Used in respiration as a source of energy
Used as a store of energy
Causes of variation in offspring (5)
Meiosis
Mutations in DNA
Environmental factors
Random mating
Random fertilisation
How do you use a variegated leaf to show chlorophyll is needed for photosynthesis - first step
Draw the pattern of chlorophyll (the green parts of the leaf)
Why do very high temperatures reduce growth of plants
More transpiration, so more water loss
Which leads to wilting, and the stomata close to prevent further loss
Which means that there is less uptake of carbon dioxide in the plant
So less photosynthesis
The enzymes are denatured which also means less photosynthesis
Consequences of a diet too high in fat
Obesity
Blockage of arteries (as there is a build-up of plaque in the walls of arteries)
Leading to coronary heart disease
High blood pressure
Diabetes
Joint damage
Gall stones
Improve: heat is radiated
Heat loss by radiation
Why does grass in a food web contain energy
Photosynthesis converts light energy into chemical energy, in the form of glucose
Why might the average height for some males be higher than females
Genes on the Y chromosome are different to on the X
Difference in diet
Different metabolic rates
Hormones
How can you tell if a disease is hereditary or not
Look at family history
Was the patient born with the condition
Carry out a DNA test
Why can plants not absorb all light energy that reaches them from the sun
Some of the light is reflected, and some light falls on flowers
Why is the composition of air in the alveoli different from exhaled air
Exhaled air is a mixture of inhaled air and alveolar air
No gas exchange occurs in trachea
As it only occurs at the alveoli
Osmoregulation definition
The control of the water and salt balance in the body
What is a partially permeable membrane
A membrane that allows water to pass through, but does not allow charged particles to pass through
Biodiversity definition
A measure of the variation shown by organisms in an ecosystem, based on the number and abundance of different species
Two reasons why many eggs are needed for cloning to be successful
Not all embryos implant in the uterus of the surrogate mother, not all eggs survive
Apart from sterilises-kills other bacteria-reduces competition, why is steam used to clean an industrial fermenter
It reduces contamination, and steam leaves no residue, only water
Why can stem cells repair a damaged heart
They can differentiate into any type of specialised cell, then can divide by mitosis to form tissues
Why is protein in urine an indicator of high blood pressure and kidney damage
Proteins normally do not pass through the basement membrane into the Bowman’s capsule, as they are too large. High blood pressure will force the protein molecules out, which results in damage to the glomerulus.
How does the temperature recorder do its thing in a fermenter
The temperature recorder detects changes in the temperature of the solution in the fermenter, and controls the water in the cooling jacket to maintain the optimum temperature for enzymes. If the temperature is too low, there is no water in the cooling jacket; if it is too high, cold water is released into the cooling jacket, to lower the temperature to prevent enzymes from denaturing.
Function of vitamin C
Forming skin and connective tissues
Impacts of excess energy/carbohydrate in the diet
Obesity and diabetes
Negatives of cloning animals
Genetically identical so reduced genetic variation in population, meaning it is more vulnerable to disease. Shorter lifespan
Why might producers have lower biomass than primary consumers
Producers are being continually consumed
Note 
Flashcard (24)