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106 Cards in this Set
- Front
- Back
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Name the 5 parts of an animal cell |
Nucleus Cytoplasm Cell Membrane Mitochondria Ribosomes |
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What is the function of the nucleus? (2) |
Controls the activities of the cell Contains genetic information |
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What is the function of the cytoplasm? |
It is where most of the chemical reactions take place
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What is the function of the mitochondria? |
This is where most of the energy is released in respiration |
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What is the function of the ribosomes? |
It is where protein synthesis occurs |
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Name the three parts that plants have but animals don't have |
Cell Wall Chloroplasts Vacuole |
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What is the function of the cell wall? |
Strengthens the cell |
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What is the function of the chloroplasts |
Absorbs light energy to make food |
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What are the three parts of a bacterial cell? What does it not have? |
Cytoplasm, cell membrane and cell wall No nucleus |
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What is diffusion? |
Spreading of particles of a gas or any substance in a solution, resulting in a net movement from a region where they are of a higher concentration to a region with a lower concentration. The greater the difference in concentration, the faster the rate of diffusion. |
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What is diffusion used for in the body? |
Oxygen required for respiration passes through cell membranes through diffusion |
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What is tissue? (with examples (3)) |
A group of cells with similar structure and function. Eg. muscular, glandular and epithelial |
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What is the function of muscular tissue? |
Contracts to bring about movement |
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What is the function of glandular tissue? |
Produces substances like enzymes and hormones |
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What is the function of epithelial tissue? |
Covers some parts of the body |
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What is an organ? Give an example |
Organs are made of several tissues like the stomach |
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Give three types of tissue used in the stomach (and why) |
Muscular tissue: churns the contents Glandular tissue: produce digestive juices Epithelial tissue: Covers the outside and the inside of the stomach |
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What is an organ system? |
A group of organs that perform a particular function. eg. Digestive system |
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Give the 7 organs and the 5 functions they perform in the digestive system |
pancreas and salivary glands: produce digestive juices
stomach and small intestine: where digestion occurs liver: produces bile small intestine: absorption of soluble food large intestine: water is absorbed from the undigested food, producing faeces |
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Give the 4 tissues of a plant (leaf) and give their functions |
Epidermal Tissues: covers the plant Mesophyll: carries out photosynthesis xylem and phloem: transports substances around the plant |
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What is the equation for photosynthesis |
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What is the role of chloroplasts in photosynthesis? |
Absorbs sunlight |
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What factors affect photosynthesis? |
Shortage of light Low temperature Shortage of Carbon Dioxide |
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How do greenhouses help increase the rate of photosynthesis? |
Artificial light Heating Supply of CO2 |
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What are 5 uses of glucose in plants? |
Produce fat or oil for storage Produce cellulose which strengthens cell wall Produces proteins Used for respiration Stored as insoluble starch |
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What mineral is required to make proteins for the plant? |
nitrate ions from the soil |
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Factors affecting an organism (5) |
Temperature
Availability of Nutrients Amount of Light Availability of Water Availability of oxygen and carbon dioxide |
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Give two ways in which the distribution of organisms can be measured |
Random sampling wit quadrats Sampling along a transect |
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What are proteins made of? |
Long chains of amino acids. These long chains are folded to produce a specific shape that enables other molecules to fit into the protein |
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Give 4 types of proteins |
Structural components of tissues such as muscles Hormones Antibodies Catalysts (speed up reactions) |
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How can high temperatures affect an enzyme? |
High temperatures change the shape of the enzyme, and the shape of an enzyme is vital for the enzyme's function |
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Amylase catalyses what into what? |
starch into sugars |
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Protease catalyses what into what? |
proteins into amino acids |
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Lipase catalyses what into what? |
lipids (fats and oils) into fatty acids and glycerol |
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Where is amylase produced? |
Salivary glands, pancreas and small intestine |
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Where is protease produced? |
Stomach, pancreas and small intestine |
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Where is lipase produced? |
Pancreas and small intestine |
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Where does amylase work? |
Mouth and small intestine |
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Where does protease work? |
Stomach and small intestine |
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Where does lipase work? |
Small intestine |
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How does the stomach form the right conditions for enzymes in the stomach to work? |
Using hydrochloric acid to lower the pH |
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What does bile do? |
Provides alkaline conditions for enzymes in the small intestine to work by neutralizing the acid added to the stomach enzymes |
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How are enzymes produced in a factory? |
Using microorganisms that produce enzymes that pass out of the cells |
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What are the advantages of biological detergent? |
It is effective at low temperatures, meaning less energy is used |
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What enzymes are used in biological detergent? |
Fat and protein digesting enzymes |
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What enzymes are used in baby foods? |
Proteases, to pre-digest the protein |
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What enzyme converts starch to sugar syrup? |
Carbohydrase |
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What is isomerase used for? |
Convert glucose syrup into fructose syrup |
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Why is isomerase better than other sweeteners? |
It is much sweeter, so can be used in less quantities in slimming foods |
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What is the disadvantage of using enzymes in industry? (2) |
Enzymes denature at high temperatures Enzymes are costly to produce |
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What are chemical reactions inside cells controlled by? |
Enzymes |
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What is aerobic respiration? |
Respiration that uses oxygen |
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What is the equation of aerobic respiration? |
glucose + oxygen ➞ carbon dioxide + water (+ energy) |
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Where does aerobic respiration take place in the cell? |
In the mitochondria |
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What is energy released by respiration used for in animals? (2) |
Build larger molecules from smaller ones Enable muscles to contract |
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What is energy released by respiration used for in mammals/birds? (3) |
Build larger molecules from smaller ones Enable muscles to contract Maintain a steady body temperature |
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What is energy released by respiration used for in plants? (2) |
To build larger molecules from smaller ones To build up sugars, nitrates and other nutrients into amino acids which are built into proteins |
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What increases during excercise? (2) |
Heart rate Breathing rate and depth |
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Why does heart and breathing rate increase during exercise? |
Increase blood flow to muscles Increase supply of sugar and oxygen Increase rate of removal of CO2 |
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What is stored glucose and why do muscles store glucose? |
Glycogen Can be converted back to glucose during exercise |
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What is anaerobic respiration? |
Incomplete breakdown of glucose and produces lactic acid |
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Why do organisms anaerobically respire? |
There is insufficient oxygen reaching the muscles |
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What is oxygen debt |
Oxygen that needs to be repaid in order to oxidise the lactic acid into CO2 and water |
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Why do muscles become fatigued during vigorous exercise? |
Build up of lactic acid in the muscles stops them from contracting efficiently |
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What is lactic acid removed by from the muscles? |
Blood flowing through the muscles |
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How do body cells divide? |
By mitosis |
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What does a chromosome contain? |
Genetic information |
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What happens during mitosis? (2) |
Copies of the genetic material are made Cell divides once to form 2 genetically identical body cells |
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Why is mitosis important? (2) |
Growth Produce replacement cells |
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What is a gamete |
Sex cell |
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How many sets of chromosomes do body cells and gametes have? |
Body cells = 2 set Sex cells = 1 set |
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What is meiosis? |
The type of cell division in which a cell divides to form gametes |
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Where does meiosis occur in the body? |
In the testes and ovaries (reproductive organs) |
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What happens during meiosis? (2) |
Copies of the genetic information are made Cell divides twice to form 4 gametes, each with a single set of chromosomes |
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What is fertilization? |
When gametes fuse to form body cells with new pairs of chromosomes |
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How does a fertilized egg become a new individual? |
The fertilized cell divides rapidly by mitosis |
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When do animal cells differentiate? |
At an early stage |
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When do plants differentiate? |
Throughout their lives |
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What are stem cells? |
Cells from human embryos and adult bone marrow |
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What is the special ability of human stem cells? |
They can differentiate into any kind of human cell |
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What are stem cells used for? |
Treatment of conditions like paralysis |
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How do organisms asexually reproduce? Meiosis or mitosis? |
Mitosis They contain the same alleles as the parents |
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Which type of reproduction gives variation? |
Sexual reproduction |
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What are the male sex chromosomes? |
XY |
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What are the female sex chromosomes? |
XX |
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What is an allele |
Different forms of a gene |
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What is a dominant allele? |
An allele that controls the development of a characteristic when it is present on only on of the chromosomes |
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What is a recessive allele? |
An allele that controls the development of a characteristic only if the dominant allele is not present |
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What are chromosomes made of? |
DNA |
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What odes DNA stand for? |
Deoxyribo nucleic acid |
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WHat structure does a DNA molecue have? |
double helix |
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What is a gene? |
A small section of DNA |
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What does each gene code for? |
A particular combination of amino acids to make a specific protein |
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Is polydactly caused by a dominant or recessive allele? |
Dominant |
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Cystic fibrosis is caused by a dominant or recessive allele? |
Recessive |
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What is embryo screening useful for? |
To identify alleles that cause genetic disorders |
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Where does the evidence for the existence of early life forms come from? |
Fossils |
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What are fossils? |
Fossils are the remains of organisms from many years ago, found in rocks |
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When are fossils able to be formed and how? (4) |
From the hard parts of animals that do no decay easily From parts of organisms that have not decayed because one or more of the conditions needed for decay are absent When parts of the organisms are replaced by other materials as they decay As preserved traces of organsisms (eg. footprints) |
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Why do soft-bodied early life-forms have few traces? |
Traces have been destroyed by geological activity |
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What are the causes of extinction? (6) |
Changes to environment New predator New disease New, more successful competitors Single catastrophic event (eg. Meteor) Through speciation |
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Names the stages of new species forming (4) |
Isolation Genetic Variation Natural Selection Speciation |
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What is isolation? |
Two populations of species become seperated |
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What is genetic variation? |
Each population has a wide range of alleles that control their characteristics |
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What is natural selection? |
In each population, alleles that help the organism to survive are selected |
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What is speciation? |
The populations become so different that interbreeding is no longer possible |
