Differentiate between compounds, elements, atoms and molecules.
1. Atom: smallest particle of an element.
2. Element: substance made of one kind of atom.
3. Molecule: two or more atoms covalently bonded, smallest par tile of element or compound.
4. Compound: substance formed by two or more elements chemically combined.
What are the four fundamental types of chemical compounds found in living cells?
4. Nucleic Acid.
Define a carbohydrate. What is its function in the human body?
A Carbohydrate is a compound containing carbon, hydrogen, and oxygen in a ration of 1:2:1,
e.g. glucose, fructose, starch, cellulose, and glycogen. Function: Human body's main energy source.
Define a lipid. What is its function in the human body?
A lipid is a compound containing carbon, hydrogen, and oxygen.
Composed of two basic compounds: glycerol and fatty acids,
e.g. fats, oils, waxes. Function: Energy storage cushioning and insulation.
Define protein. What is its function in the human body?
Protein, is an organic compound made of one or more polypeptide chains of amino acids.
e.g. enzymes, gelatine, collagen and haemoglobin.
Function: structural components of cells, organic catalysts, antibodies and hormones.
Define nucleic acid. What is its function in the human body?
Organic compound made of nucleotides, e.g. DNA, RNA. Function: codes instructions for protein synthesis.
What is DNA?
Deoxyribonucleic acid; Nucleic acid that is he hereditary material of more living things; composes the genes.
What is an Enzyme?
An enzyme (or part protein) catalysts that speed up the rates of chemical reactions and allow them to occur at temperatures compatible with life.
What are the three factors affecting enzyme function?
1. Ph level. 2. temperature. 3. Relative amounts of enzyme and substrate.
What is hydrolysis?
Catabolic reaction that splits apart molecules and consumes water.
What is dehydration Synthesis?
The process where small molecules are bonded o make a larger molecule and water is released. For example, two glucose (a monosaccharide) molecules are linked to form maltose (a disaccharide)
What is an amino acid?
An amino Acid is a building block of protein. Examples are lysine, valine, arginine, alanine, glycine, serene.
What is a polypeptide?
A chain of amino acids from which a protein molecule is composed.
What is saturate fat?
Saturated fat is am acid carbon chain composed of single bonds. There are about twice as many hydrogen atoms as carbon atoms; usually solid at room temperature e.g. Lard, butter.
What is unsaturated fat:
It is a fairy acid chain that contain some double covalent bonds and fewer than twice as many hydrogen atoms as carbon; usually liquid at rom temperate, oil.
What is a nucleotide?
It is the building blocks of nucleic acid, and composed of 3 parts: 1. one nitrogenous base. 2. One five- carbon sugar (either ribose or deoxyribose. 3. One phosphate group.
Contrast riobse and deoxyribosed.
The sugar portion of a nucleotide. Ribose is present in RNA and deoxyribose is in DNA. Ribose contains one more oxygen atom than dioxyribose.
What is a purine?
A purine is a nitrogenous base wit ha double ring structure, e.g. adenine, guanine.
What is a pyrimidine?
A nitrogenous base with a single ring structure. e.g. cytosine, thymine, uracil.
Which nitrogenous bases pair in DNA? in RNA?
DNA: Adenine and thymine Cytosine and guanine. RNA: Adenine and uracil. Cytosine and guanine.
What is a coenzyme?
A non-protein substance (often a vitamin) that assists an enzyme in its functions.
What is a substrate?
The substance on which an enzyme acts.
What is a mineral?
A naturally occurring element that is important for the body to maintain health, e.g. sodium, potassium, chlorine and calcium.
What is a trace element?
An element required by the body in tiny amounts. E.g. magnesium, copper, zinc.
What is ATP?
Adenosine Triphosphate: A molecule that is the energy currency of cell metabolism in all living things. Composed of adenine, ribose and three phosphates.
Compare aerobic respiration and fermentation (anaerobic respiration). What is the net ATP production? What are the products of reaction?
Aerobic: 36 ATP are produced; carbon dioxide and water are released. Anaerobic: Two ATP's are produced; carbon dioxide and alcohol are released in alcoholic fermentation; lactic acid released in lactic acid fermentation.
What are the three phases of cellular respiration?
1. Glycolysis. 2. Krebs cycle 3. Electron transport chain.
What is Glycolysis?
The breakdown of glucose; forms pyruvic acid and ATP; occurs in cytoplasm.
What is Fermentation?
Release of stored chemical energy without the use of oxygen. Takes place in yeast and some bacteria.
What is Aerobic Respiration?
Release of stored chemical energy and the use of oxygen.
Describe the Krebs cycle (also known as the citric acid cycle, tricarboxylic acid cycle.)
A circular series of enzyme reactions during cellular respiration that consumes pyretic acid and releases energy and carbon dioxide. Occurs in the mitochondrial matrix.
What is the electron transport chain?
A series of enzymes that pick up and transfer hydrogen to its final acceptor, oxygen, producing water. Leads to synthesis of ATP. The third step of cellular respiration.
What is an Autotroph?
An organism that can make its own food from inorganic raw materials. Examples: green plants, some protists.
Define photosynthesis reaction. What are the reactants and products?
Conversion of light energy into chemical energy; food making process of autotrophs. Reactants; water, carbon dioxide. Products; glucose, oxygen and water.
What is a Heterotroph?
An organism that must feed on other plants or animals in order to obtain energy and nutrients, e.g. mammals, birds, fungi, many protists.
What is the general chemical equation that summarises photosynthesis?
6 H20 + 6 CO2 --> C6H6O6 + 6O2
In the presence of light, chlorophyll, and enzymes.
What are light reactions?
First stage of photosynthesis; light energy is absorbed, water is split to produce oxygen gas and ATP and NADPH are produced.
What is the Calvin-Benson Cycle
During photosynthesis, the series of enzyme reactions in which carbon dioxide is "fixed" (incorporated) into sugars. Sometimes called "dark reactions".
What are four factors that influence the rate of photosynthesis?
1. Light intensity.
3. Carbon dioxide concentration.
4. Oxygen concentration.