|With reference to carbohydrates explain the difference between a CONDENSATION reaction and HYDROLYSIS
|Condensation - when two monosaccharides join to form a disaccharide with the elimination of water and the formation of a glycosidic bond Hydrolysis - the addition of water to a disaccharide resulting in the formation of two monosaccharides
|State whether these carbohydrates are mono-, di- or polysaccharides and give each their role in living organisms. State whether each occurs in plants, animals or both: lactose, cellulose, glucose, glycogen
|Lactose - di - plants - animals - energy Cellulose - poly - plants - structure Glucose - mono - plants - animals - energy Glycogen - poly - animals - energy store
|What is are ISOMERS?
|Compounds that have the same chemical formula but which differ in the arrangement of the atoms
|What does POLAR mean?
|Molecules that have two ends or poles that interact differently with water and fat. A hydrophilic head is attracted to water but not to fat, whereas a hydrophobic tail mixes readily with fat but is repelled by water
|Name the products formed and the type of bond that is broken when a triglyceride is broken down
|Broken down to form one molecule of glycerol and three molecules of fatty acid with the elimination of water and the breaking of an ester bond
|Suggest why parts of organisms that move, such as seeds, use lipids as an energy store rather than crabohydrates
|When oxidised, lipids provide more than twice as much energy as carbohydrates. If fat is stored, the same amount of energy can be provided for less than half the mass. It is therefore a lighter storage product
|What is meant by metabolic water?
|Water produced from the oxidation of food is called metabolic water. When water is scarce a camel can metabolise fats
|What is HYDROPHOBIC?
|What is HYDROPHILIC?
|State two differences between a triglyceride and a phospholipid
|A triglyceride has three fatty acids, no phosphate group and is non-polar. A phospholipid has two fatty acids, one phosphate group and a hydrophilic head and a hydrophobic tail
|Which end of the phospholipid molecule lies to the outside of the membrane?
|The hydrophilic head
|State through which part of the membrane each of the following passes in order to enter or leave a cell 1) Sodium ion 2) A lipid soluble molecule
|1) Intrinsic protein 2) Phospholipid
|List the four bonds present in the tertiary structure of a protein
|Peptide Hydrogen Disulphide Ionic
|Classify the following proteins as fibrous or globular: insulin, collagen, keratin, lysozyme (enzyme)
|Insulin - globular Collagen -fibrous Keratin - fibrous Lysozyme - globular
|Why is water described as a polar molecule?
|A polar molecule carries an unequal distribution of electrical charge. The oxygen end has a slightly negative charge and the hydrogen end of the molecule has a slightly positive charge
|State the properties of water which allow the following: How are insects able to walk on water? How are fish able to live in a frozen pond? Why does sweating keep us cool?
|Pondskater - high surface tension Water has a max density at 4*c so ice floats forming an insulating layer for animals below Sweating - high latent heat
|Why are the following properties of water important to living organisms? 1) It is a universal solvent 2) It is transparent
|1) To allow chemical reactions to take place in solution 2) To allow light to pass through for photosynthesis
|What are the two major components of a virus?
|Core of nucleic acid protein coat
|What does EXOCYTOSIS mean?
|When a substance leaves a cell after being transported through the cytoplasm in a vesicle
|What does PHAGOCYTOSIS mean?
|The process by which the cell obtains solid materials that are too large to be taken i by diffusion
|The following are functions of different organelles. Name the organelle in each case: 1) Protein synthesis 2) Producing glycoproteins 3) Producing ATP 4) Produces ribosomes
|1) Ribosome 2) Golgi body 3) Mitochondrion 4) Nucleolus
|Name the organelle in each case that possesses the following structures: 1) Cristae 2) Thylakoids 3) Cisternae
|1) Mitochondrion 2) Chloroplast 3) Endoplasmic Reticulum
|What is a CENTRIOLE?
|Structure in cell division from which spindle fibres develop
|What is PLASMODESMATA?
|Strands of cytoplasm linking cells together
|List three features present in a plant cell, not found in an animal cell
|Chloroplasts Cell wall Large permanent vacuole
|State which of the following is a cell, tissue or organ Kidney, Epithelium, Muscle, Sperm
|Kidney - organ Epithelium - tissue Muscle - tissue Sperm - cell
|What does BIMOLECULAR mean?
|Phospholipid molecules stretched out to form two layers
|What is the difference between extrinsic and intrinsic proteins found in the cell membrane?
|Extrinsic proteins occur on the surface of the bilayer or partly embedded in it Intrinsic proteins extend across both layers
|Glucose is water soluble and vitamin A is fat soluble. They both enter a cell by passing across the membrane. Explain how the properties of the molecules and the structure of the membrane determine the way in which these two substances pass across
|Vitamin A is fat soluble and freely passes through the lipid bilayer. Large molecules such as glucose are insoluble in lipids and cannot pass through the non-polar centre of the phospholipid bilayer. Intrinsic proteins assist glucose to pass in and out of the cell by facilitated diffusion
|State two features of the membrane that increase the rate of diffusion
|Large surface area Thin
|Explain how an increase in temperature affects the rate of diffusion
|Increase in kinetic energy of molecules results in an increase in rate
|How does facilitated diffusion differ from diffusion
|Carrier proteins are involved in facilitated diffusion
|State one similarity and one difference between facilitated diffusion and active transport
|Both use carrier proteins; active transport requires energy/ATP; occurs against a concentration gradient
|Name two processes that involve active transport
|Muscle contraction Nerve impulse transmission Protein synthesis Uptake of minerals by roots