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82 Cards in this Set
- Front
- Back
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Nucleus
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Carries genetic information and controls the activities of the cell.
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Cytoplasm
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Where chemical reactions take place controlled by enzymes.
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Cell membrane
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Controls the passage of substances in and out of the cell.
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Mitochondria
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Where energy is released in respiration.
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Ribosomes
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Where protein synthesis occurs.
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Human and animal cell features
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Cytoplasm
Cell membrane Mitochondria Nucleus Ribosomes |
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Cell wall function and material
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Made of cellulose, it strengthens and supports the cell.
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Chloroplast
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Contains chlorophyll which absorbs light energy to make food (photosynthesis).
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Vacuole - time frame and function
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Permanent in plant cells it contains cell sap to support the plant.
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Plant cell features
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Nucleus
Cytoplasm Cell membrane Mitochondria Ribosomes Cell wall Chloroplasts Vacuole |
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Algal cells
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Also have a cell wall; they are simple and similar to plant cells.
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Bacteria cell
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Cytoplasm
Cell membrane Cell wall Genes not in a true nucleus |
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Yeast cell
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Single-celled fungus
Nucleus Cytoplasm Cell membrane Cell wall |
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Diffusion
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Particles of any solution spreading out resulting in a net movement from a region where they are of higher concentration to a region where they are of lower concentration.
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Factors which affect diffusion (3)
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Concentration gradient
Temperature Distance |
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Aggregation of similar cells
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C
Tissue O S |
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Aggregation of similar tissues
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C
T Organ - particular function S |
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Aggregation of organs
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C
T O System - works together |
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Plant organs (4)
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Stem
Root Leaf Flower |
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Epidermis - situation and function
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Covers the plant in a top layer of tissue to protect against pathogens and stop the plant losing too much water.
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Mesophyll
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Cells in a plant where photosynthesis takes place.
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Xylem tubes
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Carries the water in a plant from the roots to the leaves.
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Phloem tube function
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Carries sugar around the plant.
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Stomata - situation and function
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Holes on the lower surface of the plant which allow gases to diffuse in and out of the plant.
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Limiting factors for photosynthesis (3)
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Carbon Dioxide
Temperature Light intesity |
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Glucose usage in plants (6)
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Respiration
Starch (insoluble for storage) Cellulose (for cell walls) Chlorophyll Fats and Oils (for storage) Turning sugars and nitrates into amino acids (protein). |
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Factors affecting living organisms (8)
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Temperature
Nutrients Light Water Oxygen Carbon dioxide Competition Pollution |
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Liver
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Produces bile
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Salivary glands
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Produces amylase
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Stomach - main function, enzyme(s) produced and tissue's functions
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Is where digestion occurs: has muscular tissue to chum the contents; glandular tissue to produce protease and hydrochloric acid, and epithelial tissue to cover the inside and the outside lining to protect it from being damaged by the acid.
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Small intestine function and enzyme(s) produced
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Is where digestion occurs: produces amylase, protease and lipase to absorb the soluble food.
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Large intestine
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Is where water is absorbed from undigested food to produce faeces.
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Gallbladder function
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Stores bile before the bile being released into the small intestine. Bile neutralises the acid that was added to the food in the stomach. This produces the optimum conditions for the small intestines (alkaline).
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Amylase - function and where used
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An enzyme which turns starch into sugar.
Small intestine, salivary glands and the pancreas |
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Protease - function and where used?
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An enzyme which turns proteins into amino acids.
Stomach, small intestine and pancreas |
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Lipase - function and where used
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An enzyme which turns lipids into fatty acids and glycerol.
Small intestine and pancreas |
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Aerobic respiration equation
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Glucose+oxygen->carbon dioxide+water(+energy)
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Photosynthesis equation
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Carbon dioxide+water+light energy->glucose+oxygen
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Humans can use energy released during respiration for: (4)
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Building larger molecules out of smaller ones
Muscles contracting Maintaining a steady body temperature Making amino acids out of nitrate ions and sugar |
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During exercise the heart rate and depth of breathing.... Why?
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Increases so that more blood supplying oxygen and energy can be transported to the cells - increasing the rate of the removal of carbon dioxide.
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Anaerobic respiration equation
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Glucose->lactic acid (+ a little energy)
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Oxygen debt meaning and situation
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The build up of lactic acid during anaerobic respiration which demands oxidising the lactic acid afterwards to make up for it.
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Oxygen debt equation
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Lactic acid+oxygen->water+carbon dioxide
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Genotype
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The combination of alleles
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Phenotype
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A characteristic; the effect from the alleles
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Heterozygous
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Two different alleles
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Homozygous
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Two identical alleles
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Amino acids
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Building blocks of proteins
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Examples of proteins
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Antibodies
Biological catalysts - enzymes Hormones Muscle |
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Enzyme
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Increase the rate of chemical reactions
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Enzymes at home
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Biological detergents (washing powder) - protease and lipase to break down protein (blood) and fat (grease) out of our clothes
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Advantages of enzymes
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Work at lower temperature (35 degrees) - less energy used making it cheaper and more environmentally friendly.
Can be reused |
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Enzymes in industry (3)
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Baby food add protease to break down the long proteins - becomes predigested which is easier for babies to eat.
Starch can be turned into sugar syrup (food additive) by using carbohydrase. Glucose syrup can be turned into fructose syrup using isomerase which is sweeter and can therefore be added in smaller amounts - useful for slimming products |
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Disadvantages of enzymes (2)
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Cost a lot to produce (through fermentation)
Can easily denature if temperatures go too high |
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Multicellular organisms
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Become adapted for specific functions and develop systems for exchanging materials.
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Shape of an enzyme
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Fits a specific substrate using the "lock and key" method.
Becomes denatured under high temperatures meaning that the enzyme cannot fit the substrate anymore. |
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Muscle stores...
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Glycogen which can be converted back into glucose for use during exercise
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Long periods of vigorous activity result in...
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Muscles become fatigued i.e. stop contracting due to the build up of lactic acid. Blood which brings oxygen removes it.
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Mendel's experiment and what this meant
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He bred two purebred peas with different colours/heights which resulted in the offspring having dominant phenotypes. By then breeding two of these heterozygous peas he created a variety of phenotypes - proving that genes did not blend and that two pieces of DNA are taken to account.
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Why was Mendel's work not appreciated until many years after his death?
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His work preceded the discovery of chromosones
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Stem cells - what are they, how can they be found and what are its capabilities?
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Unspecialised and undifferentiated bunch of cells which form about 5 days after fertilisation from human embryos which have the potential to become any cell. They can be also be taken from adult bone marrow
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Advantages of stem cells
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Could potentially help Parkinson's and paralysis.
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Sexual reproduction - what actually happens?
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Each gamete contains 23 pairs of chromosones which when fused gives rise to variation.
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XX
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Female
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XY
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Male
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Chromosones
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Large molecules of DNA which have a double helix structure
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Polydactyly
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Having extra fingers or toes which is caused by a dominant allele
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Cystic fibrosis
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Disorder of cell membranes which is caused by a recessive allele
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Embryo screening
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A way of checking embryos to see if they carry the alleles for particular diseases
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Against stem cells
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Essentially killing a person.
Not our right. |
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Advantages of embryo screening (2)
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Could eradicate diseases and so the person would have a better quality of life
It would save costs on future drugs |
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Against embryo screening (2)
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Could lead to choosing a specific gender and carriers could be discarded (killed).
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Fossil
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Evidence for early forms of life
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How are fossils formed? (4)
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From hard parts such as teeth which do not decay easily
When one or more of the conditions needed for decay is absent When parts of the organism are replaced by other materials as they decay Preserved traces such as footprints, burrows and rootlets. |
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Problems faced by fossils
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Many early life forms were soft bodied and so did not leave any traces behind
Traces can be destroyed by geological activity |
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What can we learn from fossils?
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How much or little organisms have developed and changed over time
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How may extinction occur? (6)
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Changes to the environment which the animal is not adapted for
New predators New diseases More successful competition Catastrophic event i.e volcanoe Cyclical nature of speciation |
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Speciation
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When populations become so different that interbreeding is no longer possible
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Isolation
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Two populations of a species become separated
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Genetic variation
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Wide range of alleles that control their characteristics
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Natural selection
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The specific alleles which control characteristics to help them survive are selected and so can be passed on
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New species arise by (4)
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1.Isolation
2.Genetic variation 3.Natural selection 4.Speciation |
