OCR Additional Science - Unit 3 - Biology

Question	Answer
What do Cells contain?	Cytoplasm Cell Membrane Nucleus Mitochondria Ribosome
What is the function of Cytoplasm?	Where chemical reactions take place.
What is the function of the Cell Membrane?	Controls what enters or what exits the cell.
What is the function of the Nucleus?	Contains the genetic information and controls what it does.
What is the function of the Mitochondria?	This is where respiration takes place, supplies cells with energy.
What is the function of the Ribosome?	The microsized cytoplasm where protein synthesis takes part.
What cells have high levels of Mitochrondia?	Sperm Cells Muscle Cells Liver Cells. These cells require high levels of energy, therefore they have more mitochondia.
Which order do the following go: Gene Nucleus Chromosome	Nucleus Chromosome Genes. Chromosomes are found in the nucleus, genes are a section of chromosomes.
What are genes?	Genes are a section of the chromosomes, that carries and controls a particular inherited characteristic.
What are Chromosomes?	Chromosomes are long coiled molecules of DNA. These are divided into sections (genes). These are made from a chemical called DNA.
How many PAIRS of chromosomes do humans have?	23 PAIRS, 46 individual chromosmes.
What does the DNA control?	Production of Protein.
What is a DNA molecule made of?	Two coiled strands around each other called a double helix.
What are the four bases in DNA?	A+T G+T
What are the four bases called?	Complementaring Base Pairing
Who formed the model of DNA?	Watson + Crick
Where is protein made?	In the cytoplasm, it creates a copy of the gene as the original gene cannot leave the nucleus.
How many bases represent 1 amino acid?	3 bases represent 1 amino acid.
What are proteins?	Long Chains of Amino Acids.
What are the functions of Protein?	Structural: Collagen, Horomes: Insulin, Carrier Molecules: Haemoglobins, Enzymes. (There are over 19'000 different proteins in a human.)
What do enzymes act as, and what is their function?	Enzymes act as Biological Catalysts. They speed up chemical reactions.
Are enzymes complex?	Enzymes are very complex, they are specific and each individual enzyme speeds up a particular reaction,
What can affect the rate of reaction of an enzyme?	Changes in temperature or PH.
Describe the structure of a enzyme.	Each enzyme has an active site, that only a specific reactants can only fit into.
What can prevent an enzyme from working?	High temperature and Exteme pH can damage an enzyme.
What can cause gene mutations?	They can be spontaneous, but environmental factors can contribute. E.g. exposure to radiation.
What can mutations lead to, protein wise?	Lead to production of different proteins.
What is Aerobic Respiration?	Respiration while, oxygen is present and energy is found in glucose.
In respiration, what does exercise to?	Increase the demand of energy, so the pulse rate increases which allows more blood to flow, therefore allows more glucose and oxygen, while more CO2 is removed.
Equation of Aerobic Respiration:	Glucose + Oxygen -> Carbon Dioxide + Water (+Energy Release)
What is Anaerobic Respiration?	This occurs when muscles are working hard, and the oxygen cannot be supplied at a satisfactory level to break down all glucose.
What is the product of Anaerobic Respiration?	Lactic Acid.
Equation for Anaerobic Respiration:	Glucose -> Lactic Acit (+Small amounts of energy release)
What does your body do after Anaerobic Respiration to prevent cell damage from the product (Lactic Acid)?	Deep Breathing - So oxygen is taken in and breaks down lactic acid - producing CO2 and H20. Heart Rate Stays High - Pumps blood through muscles to remove lactic acid, transports this to the liver where it is broken down.
LIst advantages of Multicelluar Organisms:	Allow organisms to be larger, Allow cells to differentiation, Alllow organisms to be complex.
Why do Multicelluar organisms require development of specialised organs systems?	Cell Communication, Supplying cells with nutrients, Controlling exchange with the environment.
What are diploid body cells, and which organisms have them?	Mammal cells normally have diploid body cells, these contain two matching sets of chromosomes.
What are haploid cells?	Cells containing only 1 set of of chromosomes.
Haploid / Diploid: What are gametes?	Specialised haploid cells.
Haploid / Diploid: What happens at fertilisation?	Gametes combine producing a diploid zygote. Genetic material from parents combined.
Describe what happens with the sperm cell during fertilisation, and what the effect to the egg is?	A sperm consists of a tail and the cell is very small, helping it be mobile. The cell contains a lot of mitochondrias supplementing it with lots of energy to swim. On contact with the ovum, the acrosome bursts, this is in the head section of the sperm. Once it bursts, this releases enzymes which digest the cell membrane of the egg and allow the sperms nucleus to be inserted. This contains one set of the chromosome. The eggs surface then changes texture preventing any other sperm from entering.
How many chromosomes does a gamete have?	23 Chromosomes - half come from each parent.
What is mitosis?	New cells for growth is mitosis. These cells are genetically identical.
What's meiosis?	Type of cell division which occurs in the testes and ovaries.
What does The Blood contain, and what is the function of these 4 components?	Platelets: Clump together when blood vessel becomes damaged, produces a clot. Plasma: transport substances around the body including: food like glucose, water, hormones, antibodies and waste products. White Blood Cells: Protect the body against pathogens. Red Blood Cells: Transports oxygen from lungs to tissue. These are small and flexible so they can pass through narrow blood vessels - they do not contain a nucleus allowing more space for haemoglobins.
Describe the shape and size of the red blood cell and the reason associated.	Small size and biconcave shape gives red blood cells a large surface area to volume ratio, for absorbing oxygen. Oxygen is diffused to the lungs through the lungs.
What is the equation for the creation of Oxyhaemoglobins.	Haemoglobin + Oxygen -> Oxyhaemoglobin.
What does the blood move through around the body?	Arteries, Veins, Capillaries.
Describe the function of: Arteries, Veins, Capillaries.	Arteries carry the away from the heart. Veins carry the blood to the heart. Capillaries allow material exchanges to occur.
What does the right hand side of the heart do?	Pumps low oxygen blood to the lung and back.
What does the left hand side of the heart do?	Pumps blood with oxygen around the body and back.
What is a Double Circulatory System and where is it found?	Found in mammals. Consists of two loops, advantage is that blood pumped around the body is under much more pressure than lungs. Provides a greater rate of flow to the body tissues.
What are the adaptations for: Arteries, Veins, Capillaries.	Arteries: Thick walls made of elastic muscle fibers - this is to cope with the pressure. Veins - Valves to prevent back flow of blood. Capillaries: Thin permeable (allows liquid and gases to pass through) walls, allow exchange of substances.
What do the ventricles do in the heart?	Contract to pump out blood out.
State the functions of right ventricle and left ventricle.	Right - Pump blood to the lungs (short). Left - Pumps blood around body. These are more muscular, blood under high pressure.
What does the Atria do?	Receives blood coming to the heart (from veins).
What are the names of the valves which prevent the blood flowing wrong direction?	Semilunar, tricuspid and bicuspid valves.
What do Plant & Animal Cells contain?	Nucleus Cell Membranes, Cytoplasm.
What do Plant Cells contain in addition?	Nucleus Cell Membrane Cytoplasm / In addition: Chloroplasts Cellulose Cell Wall, Vacole.
Found in Plant Cells, what is the function of: Cellulose Cell Wall	Strengthens & Supports the Cell
Found in Plant Cells, what is the function of: Cytoplasm	Chemical reactions occur here.
Found in Plant Cells, what is the function of: Permanent Vacuole	Filled with Cell Sap, Supports Cells.
Found in Plant Cells, what is the function of: Cell Membrane	Controls movement into and out cells.
Found in Plant Cells, what is the function of: Chloroplast	Contains chlorophyll, this is used for photosynthesis.
Found in Plant Cells, what is the function of: Nucleus	Controls function of cells and contains genetic information.
Found in Plant Cells, what is the function of: Ribosome	Protein Synthesis occurs here.
How do animals grow?	By increasing the amount of cells.
Difference in animals and plants growth.	Animals grow to a finite size, whereas plants can grow forever.
How do plants gain height?	Through Cell Enlargement.
How can Growth be measured?	Dry Mass (Best Way), Wet Mass, Height.
Where is cell division restricted to in plants?	Meristem (gorwing tips of roots and shoots).
Advantages and disadvantages of measuring growth by: Height	Advantage: Easy and quick measurement. Disadvantage: Increase of mass may occur without increase of height.
Advantages and disadvantages of measuring growth by: Wet Mass	Advantage: Not destructive, and easy to measure. Disadvantage: Water content in living tissues varies and could produce an overall distorted view.
Advantages and disadvantages of measuring growth by: Dry Mass	Advantage: Most accurate method. Disadvantage: Destructive, removing water from organisms kills.
What are Stem Cells?	Undifferentiated cells which can specialise and develop into cells, tissues and organs.
Where are stem cells obtained from?	The embryo.
Which stem cells are more useful, embryonic or adult?	Embryonic stem cells are more useful, these can develop into any sort of body cell, while adult stem cells are limited to differentiate into cell types of their tissue origin.
What is selective breeding?	Animals or plants with good characteristics are selected and deliberately cross-bred to produce offspring.
How can Selective Breeding improve agriculture yields in plants and animals? E.g. Cows.	Quantity of Milk - cows have been bred to produce high daily milk volumes. Quality of Milk - Jersey Cows have been bred to produce rich and creamy milk. Beef Production - Some cows have been bred for characteristics such as hardiness, early maturity and high offspring.
What is a disadvantage of selective breeding?	Intense selective breeding reduces gene pool and number of different alleles, this means less variation which leads to INBREEDING.
What is Genetic Engineering?	The alteration of the genetic make-up of an organism, e.g. introducing new genes from another organism.
What are the advantages of altering the genetic makeup.	Improve crop resistance: Soya plants are GM by placing a gene that makes them resistant to herbicide. Improve Quality of Food: People who have a diet consists of mainly rice can become deficient in vitamin A. A gene responsible for beta-caroteen can be transferred from a carrot to rice. Producing Required Substances: Gene which produces human insulin can be inserted into a bacteria cell, from which it can produce insulin to treat diabetes.
What is the advantages and disadvantages of Genetic Engineering?	Advantage: Allows organisms with new features to produce rapidly. Disadvantage: Inserted genes can have unexpected side effects.
What's Gene Theraphy?	Changing a person's genes in an attempt to a genetic disorder.
What is asexual reproduction?	When organisms produce identical copies. Plants can reproduce asexually.
What are the advantages of Cloning Plants?	Will be genetically be identical to parents, all characteristics are known. Becomes possible to mass produce plants which are hard to grow from seeds.
What are the disadvantages of Cloning Plants?	Plants which are susceptible to disease or environmental conditions will affect all plants. Reduces genetic variation which reduces potential to further selective breed.
How does Cloning by Tissue Culture work?	Select parent plant with desired characteristics. Scrape of small pieces of tissue into a beaker containing nutrients and hormones. This is to be done without the presences of bacteria (aseptically). Lots of genetically identical plantlets will grow.

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OCR Additional Science - Unit 3 - Biology

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