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110 Cards in this Set
- Front
- Back
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What do both animal and plant cells have?
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Cytoplasm Cell Membrane Mitochondria Ribosomes |
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What features do just plant cells contain?
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Chloroplasts Vacuole |
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What does a nucleus do?
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Controls the activities of the cell |
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What does a cytoplasm do? |
Where most of the chemical reactions take place |
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What does a cell membrane do? |
Controls the passage of substances in and out of the cell.
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What do mitochondria do? |
Where most energy is released in respiration. |
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What do the ribosomes do?
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Where protein synthesis occurs. |
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What does the cell wall do? |
Made of cellulose and strengthens the plant cells. |
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What do chloroplasts do? |
Absorb light energy to make food in plant cells. |
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What does the vacuole do? |
Filled with cell sap in plants. |
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What is yeast and what are the features?
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The cell has a nucleus, cytoplasm, cell membrane and a cell wall. |
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What is bacteria and what are the features? |
Bacterium is a single-celled organism. A bacterial cell consists of a cell wall, cell membrane, cytoplasm, ribosomes, DNA, plasmid and flagella. The genes (DNA) are not in a distinct nucleus. |
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What is diffusion? |
Diffusion is the spreading of the particles of a gas or any substance in solution. The particles would move from a region of high concentration to a region of low concentration. |
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How does oxygen relate to diffusion?
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Oxygen required for respiration passes through cell membranes by diffusion. |
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What does the digestive system consist of? |
The Stomach The Liver The Large Intestine The Small Intestine |
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What happens in the glands?
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Glands, such as the pancreas and salivary glands, produces digestive juices. |
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What happens in the stomach and small intestine? |
Where digestion occurs.
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What happens in the liver? |
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What happens in the small intestine?
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What happens in the large intestine? |
Where water is absorbed from the undigested food, producing faeces. |
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What are epidermal tissues? |
A type of plant tissue which covers the plant.
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What is mesophyll? |
It carries out photosynthesis. |
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What are xylem and phloem? |
They transport substances around the plant. |
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What is the meaning of Photosynthesis?
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Making glucose using light. |
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What happens during the process of photosynthesis? |
This energy is used by converting carbon dioxide (from the air) and water (from the soil) into sugar (glucose). Oxygen is released as a by-product. |
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What is the photosynthesis equation? |
carbon dioxide + water ---(light energy)---> glucose + oxygen |
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What three factors limit the rate of photosynthesis?
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2) Carbon Dioxide 3) Light Intensity |
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Where does photosynthesis happen?
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*Leaves are the main site of photosynthesis. *Photosynthesis mainly occurs in mesophyll cells. *These cells contain lots of chloroplasts. *Chloroplasts contain chlorophyll. |
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In what ways do plants and algae use glucose? (Name at least 3) |
*The glucose produced in photosynthesis may be converted into insoluble starch for storage. *Plant cells use some of the glucose produced for respiration. *To produce fat or oil for storage. *To produce cellulose, which strengthens the cell wall. *To produce proteins. |
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In farming, how do they control the limiting factors of photosynthesis?
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They grow plants in greenhouses or in polythene tunnels. They can control the temperature in greenhouses using heaters and ventilation. They can artificially increase the carbon dioxide levels. They can control the light using fluorescent lamps. |
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What are the physical factors that may affect organisms? |
*Availability of nutrients *Amount of light *Availability of water *Availability of oxygen *Availability of carbon dioxide |
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What are protein molecules made up of?
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These long chains are folded to produce a specific shape that enables other molecules to fit into the protein. |
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What do proteins act as?
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*Hormones *Antibodies *Catalysts |
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What are Enzymes?
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Enzymes are biological catalysts. Catalysts increase the rate of chemical reaction.
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What are enzymes made up of?
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Enzymes are protein molecules made up of long chains of amino acids. These long chains are folded to produce a special shape which enables other molecules to fit into the enzyme. |
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Why is the shape vital for the enzymes function?
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Normally only one type of molecule (the substrate) will fit into the enzyme. The active site is the part of the enzyme which the substrate fits into. |
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What is the effect of temperature on enzymes? |
The rate of enzyme-controlled reactions increases as the temperature increases. The enzyme and substrates move around faster so they collide more often. The temperature when the enzyme is working fastest is called the optimum. This is true up to approx. 40C, higher than this the structure of the enzyme changes. |
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What is the effect of pH on enzyme? |
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Where are digestive enzymes produced? |
The digestive enzymes are produced by specialised cells in glands and in the lining of the gut. |
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What do enzymes do during digestion? |
The enzymes pass out of the cells into the gut where they come into contact with food molecules. They catalyse the breakdown of large molecules into smaller molecules. |
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What is digestion? |
Digestion is the process where food is broken down into substances the body can absorb.
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What is nutrition?
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Nutrition is the process of taking in and using food. |
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What happens in the digestion in the mouth? |
Food is chewed to create a larger surface area for the action of enzymes. Saliva is released which contains amylase. Amylase digests starch into smaller sugars. Further chewing enables swallowing. The food enters the oesophagus. |
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What happens in the digestion in the stomach? |
*The walls of the stomach produce juice. *The juice contains a protease enzyme (pepsin) which digests proteins into amino acids, Hydrochloric acid which kills bacteria in the food and creates pH3 and Mucus which protects the wall of our stomach from acid and pepsin. *Food leaves our stomach to the small intestine. |
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What two main jobs does the small intestine have?
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To absorb the soluble products of digestion into the blood. |
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What three juices are released in the small intestine?
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1) Bile 2) Pancreatic Juice 3) Intestinal Juice |
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Where is Bile; produced, stored and released?
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Produced by the liver. Stored in the gall bladder. Released in the small intestine. |
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What are the two main things in bile?
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2) Bile salts which convert large fat droplets to small fat droplets. |
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What three main enzymes does the pancreatic and intestinal juice contain?
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2) Protease 3) Lipase |
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What do Amylase enzymes do? |
Complete the digestion of starch into sugars. |
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What do Protease enzymes do?
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Complete the digestion of proteins into amino acids. |
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What do Lipase enzymes do? |
Breaks down fats into fatty acids and glycerol.
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What is the main use of using enzymes in the home and what are the advantages?
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Using them for biological detergents. >More efficient at removing stains from clothes >Lower washing temperatures can be used which saves energy. |
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What are the disadvantages of using enzymes in the home?
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>Can lad to irritation, allergies and dermatitis. |
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What are the three main ways enzymes are used in the industry? |
>Proteases are used to pre-digest the protein in some baby foods. >Carbohydrases are used to convert starch into sugar syrup. >Isomerase is used to convert glucose syrup into fructose syrup. |
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Respiration in cells can take place .............. or ..............?
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Aerobically or Anaerobically
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What is the definition of respiration?
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The process of transferring energy from food molecules in every living cell. |
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Is oxygen used in Aerobic and Anaerobic respiration?
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Anaerobic - No |
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What happens in aerobic respiration? |
Glucose reacts with oxygen, producing carbon dioxide and water as waste products. This takes place continuously in animals and plants. |
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What is the word equation for aerobic respiration?
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Glucose + Oxygen ------> Carbon Dioxide + Water + Energy |
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How is mitochondria involved in respiration?
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The inner surface of the mitochondria is highly folded to increase the surface area for enzymes. |
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What are the changes involved during exercise with respiration?
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>The rate and depth of breathing increase. Which means more oxygen is taken into the blood and more carbon dioxide is removed from the blood. >The heart rate increases. This increases rate of blood flow to the muscles. |
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What do the changes involved during exercise do?
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All of the changes increase the blood flow to the muscles and so increase the supply of sugar and oxygen, plus, increase the rate of removal of carbon dioxide. |
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What is glycogen?
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Glucose is stored as glycogen in the muscles. During exercise, glycogen is broken down into glucose in the muscles. This increases the amount of glucose that can be respired. |
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What happens during anaerobic respiration? |
During exercise, if insufficient oxygen is reaching the muscles they use anaerobic respiration to obtain energy. |
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Anaerobic respiration is the incomplete breakdown of what and produces what?
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As the breakdown of glucose is incomplete, much less energy is released than during aerobic respiration. |
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What is the formula for anaerobic respiration?
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Glucose --------> Lactic Acid + Small amount of energy produced
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Why do we breathe in heavily during and after exercise?
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We breathe heavily to take in extra oxygen to oxidise the lactic acid which is poisonous to body; the reason why we can only tolerate small amounts or we begin to experience muscle fatigue. |
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What is the formula for when we breathe in during anaerobic respiration?
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Lactic Acid + Oxygen ------> Carbon Dioxide + Water |
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How many chromosomes are there in the typical human body cell?
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23 pairs of chromosomes (46 in total) |
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Where do we get our chromosomes from?
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We inherit one set of 23 chromosomes from each of our parents.
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What large molecule are chromosomes made up from?
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The large molecule is called DNA (Deoxyribose Nucleic Acid)
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Explain the DNA structure.
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DNA consists of two strands coiled into a double helix structure.
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What are the two main roles of DNA?
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2) Its code is used to synthesise proteins. |
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Explain a gene.
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A gene is a small section of DNA. Each gene codes for a particular combination of amino acids which make a specific protein. These proteins determine our characteristics. Some characteristics are controlled by a single gene. |
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When do new body cells produce?
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>To repair damaged tissues. >To replace worn out tissues. |
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What happens when mitosis occurs?
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When the body is producing new body cells, mitosis occurs when all the new cells chromosomes are replicated and the nucleus is divided into two. |
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What are the results of mitosis?
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The results of mitosis means that there are two genetically identical nuclei. Some cells undergo cell division again and again.
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What is asexual reproduction? |
The cells of the offspring produced by asexual reproduction are produced by mitosis from the parental cells. They contain the same genes as the parents. |
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What are stem cells? |
There is currently a lot of research involving the use of stem cells to treat various diseases and injuries. |
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Why do some people not believe in taking stem cells from human embryos? |
They feel that all embryos have got the potential to become a baby, and shouldn't be used in this way. |
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What are gametes? |
Gametes are sex cells (sperm and egg cells). |
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Where are the sperm and egg cells formed? |
Egg cells are formed in the ovaries. |
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What do these cells contain?
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They are cells containing a full set of chromosomes and then divides to form cells with half the number set of chromosomes. This is when meiosis occurs. |
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What happens when meiosis occurs?
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The nucleus divides twice to form 4 nuclei. Then the cells divides twice to form four gametes where each has a single set of chromosomes. |
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What happens during fertilisation?
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A new individual (a baby) then develops by this cell repeatedly dividing by mitosis. |
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Who was Mendel? |
Mendel worked out the main principles of inheritance in the 19th century. He studied inheritance in pea plants. |
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What happened during Mendel's study into pea plants?
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He noticed that certain characteristics that were shown by two pea plants were not always shown in their offspring. However, when he crossed these offspring together, the characteristics sometimes reappeared in the next generation. |
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What did Mendel propose? |
He proposed the idea of separately inherited factors. That each individual inherits a set of factors from each of their parents but, it is the combination of these characters that determines the characteristics of an individual.
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Why were Mendel's discoveries not recognised until after his death? |
>He published his work in an obscure journal. >DNA, Chromosomes and genes were not yet discovered. >People could not accept the link between plants and humans. |
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Where are alleles found and give an example of one. |
Each gene may have different forms called alleles. For example there is a gene for eye colour. Everyone has two copies of this gene. Alleles for eye colour may be blue, brown, green etc. Therefore each person may have two different alleles for eye colour. |
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What happens when we are conceived with the genes and alleles?
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When we are conceived, we receive one copy of each gene from each parent. Therefore we have two copies of every gene, but they may be two different alleles. Different combinations of alleles may lead to differences in the characteristic. |
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What is a dominant allele?
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An allele which controls the development of a characteristic when it is present on only one of the chromosomes. |
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What is a recessive allele?
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An allele which controls the development of characteristics only if the dominant allele is not present. |
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What is a Phenotype? |
Phenotype is a description of how a characteristic is expressed. This can be influenced by genetic or environmental factors. |
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What is a genotype? |
Genotype is a description of the alleles an individual possesses for a characteristic. |
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What does a homozygous genotype have? |
Two identical alleles for a gene. |
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What does a heterozygous genotype have? |
Two different alleles for a gene.
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What are embryo screenings?
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People in families that have certain genetic disorders can have a genetic test to see if they carry the allele for the disease. If they do carry the allele, their embryos can be screened to see if it is affected. |
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What are the sex chromosomes for a female? |
XX |
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What are the sex chromosomes for a male? |
XY |
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What are the possibilities of sex determination and what is involved during the presences of the Y chromosome?
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As a foetus, we all start off with the female characteristics. The presence of a Y chromosome causes male development, whereas, the absence of a Y chromosome causes female development. The sex of the baby is determined by the sex chromosome inherited from the father. |
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Does everybody have the same DNA?
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No, each person has unique DNA - apart from identical twins. |
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Where can samples of DNA be found?
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Blood, semen and saliva. |
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What does each individuals DNA produce and how can it be used?
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This can be used; to identify criminals, to decided whether someone is the biological father/mother of a child and also in security in technology. |
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What various events can make it difficult for animals to survive?
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>Changes to the environment over geological time. >New predators may arise. >New diseases may arise. >New, more successful, competitors may arise. >A single catastrophic event, e.g. massive volcanic eruptions or collisions with asteroids. |
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What happens when organisms either evolve or don't evolve?
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If they do evolve, they are likely to develop into new species. |
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(Name at least 3) |
>From parts of organisms that have not decayed because one or more of the conditions needed for decay are absent. >When parts of the organism are replaced by other materials as they decay. >As preserved traces of organisms. |
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How are species defined?
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A species is defined as a group of organisms that are capable of breeding together to produce fertile offspring. |
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What three ways do new species arise?
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2) Genetic Variation - each population has a wide range of alleles that control their characteristics. 3) Natural selection - in each population the alleles that control the characteristic which help the organism to survive are selected. |
