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92 Cards in this Set
- Front
- Back
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What are the five parts found in animal cells? |
1) Nucleus - contains genetic material 2)Cytoplasm - gel-like substance where most chemical reactions take place, contains enzymes that control these reactions. 3)Cell membrane - holds cell together, controls what goes in and out of the cell 4) Mitochondria- respiration takes place, respiration releases energy needed for the cell to work. 5)Ribosome's- where proteins are made in the cell. |
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What three parts are found in a plant cell but not in an animal cell? |
1) Rigid Cell Wall - Made of cellulose, it supports the cell and strengthens it. 2) Permanent Vacuole - contains cell sap, a weak solution of sugar and salts 3) Chloroplasts - these are where photosynthesis occurs, which makes food for the plant. they contain a green substance called chlorophyll |
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One example of a single-celled organism which is used allot on exams. |
Yeast which is a micro-organism, has a nucleus, cytoplasm, a cell membrane and a cell wall |
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What is different about a bacterial cell? |
It has no nucleus, the genetic information just floats in the cytoplasm. |
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What is the definition of Diffusion? |
Diffusion is the spreading out of particles from an area of High concentration to an area of Low concentration. |
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What can move in and out of the cells by diffusion? |
Dissolved substance and small molecules such as Oxygen, Glucose, Amino acids and Water. |
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Why cant substance such as Starch and Proteins go through the membrane by diffusion? |
Because the molecules are too big so they can fit through. |
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What are the four main specialised cells? |
1) palisade leaf cells 2) Guard cells 3) Red blood cells 4) sperm and egg cells |
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What are Palisade leaf cells specialised for and how? |
For photosynthesis by: 1) Being packed with chloroplasts for photosynthesis. More of them are crammed at the top of the cell so they are nearer the light 2) Tall shape means a lot of surface area exposed down he side for absorbing CO2 from the air in the leaf |
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What are guard cells adapted for and how? |
To open and close Pores by: 1) special kidney shape which open and closes the stomata in a leaf 2) Thin outer walls and thickened inner walls make the opening and closing work. 3) They're also sensitive to light and close at night to save water without losing out on photosynthesis. |
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What are Red blood cells adapted for and how? |
To carry oxygen 1) Concave shape gives a big surface area for absorbing oxygen, it also helps them pass smoothly through capillaries to reach body cells. 2) They're packed with haemoglobin - the pigment hat absorbs the oxygen. 3) They have no nucleus, to leave even more room for haemoglobin. Red blood cells are an important part of the blood. |
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What are egg cells specialised for and how? |
1) main egg cell function to carry the female DNA. The egg cell contains huge food reserves to feed the embryo. 2) When a sperm fuses with the egg, the eggs membrane changes its structure to stop any more sperm getting in. this makes sure the offspring gets the right amount of DNA. |
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What are sperm cells specialised for and how?
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1) function is to get the male DNA to the female DNA. it has a long tail and a streamline head to help it swim to the egg. There are a lot of mitochondria in the cell to help provide the energy needed. 2) Sperm also carry enzymes in their heads to digest through the egg cell membrane. |
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What does muscular tissue do? |
It contracts to move whatever its attached to. |
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What does Glandular Tissue do? |
it makes chemicals like enzymes and hormones |
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What does Epithelial tissue do? |
It covers some parts of the body, e.g he inside of the gut |
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What three tissues is the stomach made up of and what do they do? |
1) Muscular tissue, which moves the stomach wall to churn up the food. 2) Glandular tissue, which makes digestive juices to digest food. 3) Epithelial tissue, which covers the outside and inside of the stomach. |
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Which organs make up the digestive system? (5) |
1) Glands the salivary glands and the pancreas which produce digestive juices 2) The stomach and small intestine which digest food 3) The liver which produces bile 4) The small intestine, which absorbs soluble food molecules 5) The large intestine which absorbs water from undigested food. |
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What tissues are in plants? (3) |
1) Mesophyll tissue - this is where most of the photosynthesis in a plant occurs 2) xylem and phloem - xylem transports Water and minerals and Phloem transports food and nutrients such as sugar and amino acids 3) Epidermal tissue - covers the whole plant |
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How is glucose produced in plants? |
By photosynthesis using the chloroplasts which contain chlorophyll, it absorbs sunlight and uses its energy to convert carbon dioxide and water into glucose and oxygen. |
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What are the four limiting factors of photosynthesis? |
The intensity of light. The volume of carbon dioxide The temperature The level of water |
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How is the Temperature a limiting factor? |
The enzymes needed for photosynthesis work more slowly at low temperatures. At around 45 degrees or higher the enzymes will get damaged/ denatured and wont be able to work. |
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How can the ideal conditions for photosynthesis be artificially created? And how? |
Most common way is by using a Green house They trap the suns heat and use ventilation to stop it being to hot they use artificial light so photosynthesis can carry on through the night The level of carbon dioxide can be controlled by a Paraffin heater. |
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What are the five ways plants use glucose? |
1) For Respiration 2) Making cell walls 3) Making Proteins 4) Stored in seeds 5) Stored as starch |
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Two methods of studying distribution |
quadrants and transect lines |
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What environmental factors affect distribution of organisms? |
1) Temperature 2) Availability of water 3) Availability of oxygen and carbon dioxide 4) Availability of nutrients 5) Amount of light |
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What is the definition of a catalyst |
A substance which increases the speed of a reaction, without being changed or used up in the reaction. |
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What conditions do enzymes need? |
The right temperature and PH |
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What are the three enzymes found in the digestive system? |
1) Amylase 2) Protease 3) Lipase |
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What does the enzyme Amylase do? |
It converts the starch into sugars |
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What does the enzyme Protease do?
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It converts proteins into amino acids |
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What does the enzyme Lipase do?
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It converts Lipids into Glycerol and Fatty acids |
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What is the purpose of Bile? |
It neutralises the stomach Acid and Emulsifies Fats. The hydrochloric acid in the stomach makes the PH too acidic for enzymes in the small intestine to work properly. Bile is alkaline is neutralises the acid. it emulsifies fats- It breaks the fat into tiny droplets. This gives a much bigger surface area of fat for the enzyme lipase to work on making the digestion quicker |
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Where in the body is Amylase, Lipase and Protease made? |
Amylase - The salivary gland, the pancreas, the small intestine. Lipase - The pancreas and the small intestine Protease - The stomach, the pancreas and the small intestine. |
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where is bile produced and stored? |
Produced in the Liver and stored in the Gall bladder. |
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Definition of Respiration |
Respiration is the process of Releasing Energy from Glucose which goes on in every cell |
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Where does Aerobic respiration take place? |
Inside the mitochondria |
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aerobic respiration word equation |
Glucose + oxygen = carbon dioxide + water + Energy |
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Four examples of what the energy released by aerobic respiration is used for. |
1) To build up Larger molecules from smaller ones (like proteins from amino acids) 2) In animals, to allow the muscles to contract. 3) In mammals and birds the energy is used to keep their body temperature steady. 4) In plants, to build sugars, nitrates and other nutrients into amino acids which are then built up into proteins. |
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How is glycogen used during exercise? |
muscles use glucose rapidly, so some of the stored glycogen is converted back to glucose to provide more energy. |
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what is anaerobic respiration? |
Its when there isn't enough oxygen available so its an incomplete breakdown of glucose which produces lactic acid. |
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Why is anaerobic respiration not the best way to convert glucose into energy? |
Because Lactic acid builds up in the muscles, which gets painful. it also causes muscle fatigue where the muscles get tired and don't contract efficiently. Also it does not release nearly as much energy as aerobic respiration. |
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What is an advantage of anaerobic respiration? |
That at least you can keep on using your muscles for a while longer? |
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Why does your body go into oxygen debt after Anaerobic respiration? |
Because you have to repay the oxygen that didn't get to your muscles in time, because your lungs, heart and blood couldn't keep up with the demand earlier on. |
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What does oxygen debt do? |
This means you have to keep breathing hard for a while after you stop exercising, to get more oxygen into your blood. Blood flows through your muscles to remove the lactic acid by oxidising it to harmless co2 and water. |
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Why are enzymes used in biological detergents? |
They mainly use protease and lipase as they are ideal for removing stains like food or blood. |
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What is one: a) Advantage of using enzymes in biological detergents b) Disadvantage of using enzymes in biological detergents |
a) They are more effective at working at low temperatures than other types of detergents b) They can cause skin irritation as the enzymes can remain in the fibres of clothing and break down the top layer of skin in places like the inside of elbows causing irritation. |
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Why are enzymes used to change foods? |
The proteins in some baby foods are 'pre-digested' using protein- digesting enzymes (protease) so they are easier for the baby to digest. |
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Advantages of using enzymes in industry: |
1) using lower temperatures and pressures means a lower cost as it saves energy 2) Enzymes work for a long time, so after the initial cost of buying them, you can continually use them. 3) They are biodegradable and therefore cause less environmental pollution. |
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Disadvantages of using enzymes in industry: |
1) Some people can develop allergies to the enzymes (e.g in biological washing powders) 2) Enzymes can be denatured by even a small increase in temperature. This means the conditions must be tightly controlled. 3) Enzymes can be expensive to produce. |
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What does DNA stand for? |
Deoxyribonucleic acid |
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What is DNA? |
It contains genetic information which tells how the organism is put together and how to make it work. Its found in the nucleus of animal and plant cells, in really long molecules called chromosomes. |
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What is a gene? |
A gene is a section of DNA which contains the instructions to make a specific protein. The gene tells the cells what order to put the amino acids together. |
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How do cells make proteins? |
Cells make proteins by stringing amino acids together in a particular order. |
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How many amino acids are used? |
Only 20 but they make up thousands of different proteins. |
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What is DNA fingerprinting used in? |
1) Forensic science - DNA taken from a crime scene can be used to compare to suspects in order to find out who did it. 2) Paternity testing - To see if a man is the father of a particular child |
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Arguments against the possibility of a national genetic database. |
Some people think it would be a big invasion of privacy, they also worry about how safe the data would be and what else it might be used for. There are also scientific problems - false positives can occur if errors are made in the procedure or if the data is misinterpreted. |
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What is Mitosis? |
Mitosis is when a cell reproduces itself by splitting to form two identical offspring. |
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When is mitosis used? |
Its used when plants and animals want to grow or to replace cells that have been damaged. |
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How does Mitosis take place? |
If the cell gets a signal to divide, it needs to duplicate its DNA - so there's one copy for each new cell. The DNA is copied and forms x-shaped chromosomes. The chromosomes then line up at the centre of the cell and cell fibres pull them apart. Membranes form around each of the sets of chromosomes becoming the nuclei f the two new cells. Lastly the cytoplasm divides. |
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What is one way that Asexual reproduction takes place. |
By using mitosis, an example of this is strawberry plants use this to form runners which become new plants. The offspring have exactly the same genes as the parent - so there is no variation. |
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What is the Definition of Meiosis |
Meiosis produces cells which have half the normal number of chromosomes. |
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What is the difference between gametes and other cells? |
Gametes have half the usual number of chromosomes. |
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How does Meiosis take place |
Before the cell starts to divide it duplicates its DNA. Then they line up the centre of the cell and cell fibres pull them apart into two cells. Then a second division takes place where again the chromosomes line up in the middle of the two cells and the fibres pull them apart from two cells to four cells which only contain 1 set of chromosomes, half the usual amount. |
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What is differentiation? |
The process by which a cell changes to become specialised for its job. |
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What is the difference between differentiation in animal cells and plant cells? |
In most animal cells the ability to differentiation is lost at an early stage, but lots of plant cells don't ever lose this ability. |
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What are stem cells? |
Cells which are undifferentiated which can develop into different types of cells depending on what instructions they're given. |
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What are the two main places Stem cells can be found in humans and what is the difference between the Stem cells. |
In early human embryos. - the cells have the potential to turn into any kind of cell. In adults bone marrow - these aren't as versatile as embryonic stem cells, they can't turn into any cell type only certain ones. |
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How are Stem cells used in medical treatment? |
To cure diseases. The stem cells can be grown to replace faulty ones that are making people sick. Such as making beating heart muscle cells for people with heart disease. insulin producing cells for diabetes. Nerve cells for people paralysed by spinal injuries. |
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Why are some people against stem cell research? |
1) because some people feel that human embryos shouldn't be used for experiments since each one is potential life. 2) In some countries stem cell research is banned but it's allowed in the UK as long as it follows strict guidelines. |
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Why are some arguments for stem cell research? |
1) some think that curing patients who already exists and are suffering is more important than the rights of embryos. 2) The embryos usually used in the research are usually unwanted ones from fertility clinics which if were not used for research would probably be destroyed. |
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What do the X and Y chromosomes decide? |
What gender you are. |
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Who was Gregor Mendel and what did he do? |
Gregor Mendel was an Austrian monk who on his garden plot at the monastery noted how characteristics in plants were passed on from one generation to the next. |
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What year was Gregor Mendel's research published? |
1866 |
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What where Mendels's three important conclusions? |
1) Characteristics in plants are determined by hereditary units 2) Hereditary units are passed on from both parents, one unit from each parent. 3) Hereditary units can be dominant or recessive - if an individual has both the dominant and the recessive unit for a characteristic, the dominant characteristic will be expressed. |
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What are hereditary units known as now? |
genes. |
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What are Alleles? |
Different versions of the same gene. |
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What is homozygous |
If an organism has two alleles the same for a particular gene. |
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What is hetrozygous? |
if an organism has two different alleles for a particular gene. |
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What is Cystic Fibrosis caused by? |
A recessive Allele |
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What is cystic Fibrosis and what does it cause? |
It is a genetic disorder of the cell membranes. It causes the body to produce a lot of thick sticky mucus in the air passages and in the pancreas. |
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In order for a child to have cystic fibrosis ... |
...Both parents must be either carriers of suffers of the disease. |
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What is Polydactyly caused by? |
A dominant Allele |
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What is Polydactyly and what does is cause? |
It is a genetic disorder where a baby is born with extra fingers or toes, it is not life threatening. |
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When can embryos be scanned for genetic diseases? |
During In Vitro Fertilisation (IVF) |
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Arguments against Embryonic screening. |
1) may become a point where people want to screen their embryos to pick the most desirable. 2) It implies that people with genetic engineering are undesirable - could increase prejudice. 3) screening is expensive 4) The rejected embryos are destroyed, these are potential lives which may be seen as murder to some religions. |
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Arguments for Embryonic screening. |
1) it will help to stop people suffering 2) There are laws to stop it going to far - such as parents cannot even select the sex of their baby unless its for health reasons 3) During IVF most embryos are destroyed anyway, screening just allows the selected one to be healthy 4) Treating disorders costs the government and taxpayers allot of money |
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What are fossils? |
Fossils are the remains of plants and animals which are found in rocks. |
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Fossils can form in rock by three ways: |
1) From gradual replacement by minerals 2) From Casts and impressions 3) From Preservation in places where no decay happens |
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What are the six ways extinction can happen? |
1) The environment changes too quickly for them to adapt. 2) A new predator kills them all. 3) A new disease kills them all 4) They can't compete with other species for food. 5)A catastrophic event happens that kills them all. 6) A new species develops |
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What is Specification? |
The development of a new species |
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What two things lead to Specification? |
Isolation and Natural selection |
