biology unit 1

Created by

QuietImpala58095

Cards (87)

describe the structure of a water molecule
1 oxygen atom covalently bonded to 2 hydrogen atoms.
oxygen is more electronegative than hydrogen which leads to polar bonds and an uneven charge distribution.
what is a hydrogen bond?
a type of strong intermolecular force
hydrogen atoms which are directly covalently bonded to a highly electronegative atom are attracted to highly electronegative atoms in other molecules
what is a solvent?
any substance which solutes can dissolve in to form a solution
state 6 important properties of water
acts as a solvent
acts as a metabolite
high surface tension
high specific heat capacity
high latent heat of vaporisation
strong cohesion and adhesion forces
why is cohosion useful in biological systems?
cohosion is the main force supporting columns of water as they are pulled up the xylem in plants. the water molecules stick together as a constant column.
why is adhesion useful in biological systems?
it allows water to move against the pull of gravity up the xylem.
what are carbohydrates?
molecules that consists of carbon, hydrogen and oxygen only.
what are monosaccharides? 
1 individual monomeric sugar unit
what is a disaccharide?
2 monosaccharides covalently linked by a glycosidic bond
what is a polysaccharide?
a polymer made up of many monosaccharides covalently linked by glycosidic bonds
what is a glycosidic bond?
a type of bond which joins a monosaccharide to another molecule
what type of reaction forms a glycosidic bond?
a condensation reaction
describe what happens in a condensation reaction
2 molecules are joined together and water is removed
what type of reaction breaks a glycosidic bond?
a hydrolysis reaction
describe what happens in a hydrolysis reaction
a molecule is broken apart using water
describe the structure of a glycogen
made up of many alpha glucose molecules joined by either alpha 1-4 or alpha 1-6 bonds
highly branched
compact
why is glycogen useful as a storage molecule in animals
it is highly compact
it is highly branched so it can be broken down by enzymes easily for respiration
it is insoluble
describe the structure of starch
made of amylase(joined by alpha 1-4 bonds) and amylopectin( joined by alpha 1-4 and 1-6 bonds)
coiled and branched
what is the difference between saturated fatty acids and unsaturated fatty acids?
saturated fatty acids have c-c single bonds while unsaturated fatty acids have c-c double bonds
what is an ester bond?
a type of covalent bond which is found in triglycerides and phospholipids. ester bonds join the fatty acid tails to the glycerol molecule
what 3 elements are triglycerides made up of
carbon, hydrogen and oxygen
describe the structure of a triglyceride
1 molecule of glycerol attached to 3 fatty acid chains by ester bonds. fatty acids may or may not contain double bonds.
why do large multicellular organisms need transport systems?
they have a small surface area to volume ratio and high metabolic rate, therefore the rate of diffusion alone would not be fast enough to transport substances to where they are needed
give 4 examples of substances transported within organisms
oxygen is transported in for respiration
CO2 is transported out from respiration
dissolved food molecules from digestion
waste products such as urea in humans
what is mass transport?
the bulk transport of substances to all parts of an organism using mass flow
give features of a mass transport system
vessels
transport medium
a mechanism for maintaining a flow
what is the difference in function between veins, arteries and capillaries?
arteries carry blood away from the heart
veins carry blood towards the heart
capillaries flow close to tissues for exchange
describe the structure of arteries
they have thick walls made of muscle and elastic tissue and a small lumen to transport blood under high pressure
describe the structure of capillaries
they have thin walls about 1 cell thick to allow for easy exchange of substances at the tissues
describe the structure of veins
they have less muscle and elastic tissue than arteries and they have a larger lumen as the blood is at lower pressure. also have valves to prevent backflow.
human heart diagram
.
what is the name of the main artery which takes oxygenated blood out of the heart for transport around the body
the aorta
what is the name of the main vein which carries deoxygenated blood from the body into the heart
the vena cava
what is the name of the main artery which supplies the heart tissues with oxygenated blood
the coronary artery
what is the name of the artery which transports deoxygenated blood from the heart to the lungs
pulmonary artery
what is the name of the vein which transports oxygenated blood from the lungs back to the heart?
the pulmonary vein
what is the cardiac cycle?
the sequence of events involved in 1 cycle of contraction and relaxation of the heart. it involves 3 stages: atrial systole, ventricular systole and diastole.
describe what happens during atrial systole
the atria contract, pushing any remaining blood into the ventricles
describe what happens during ventricular systole 
the ventricles contract. the tressure increases, closing the atrioventricular valves to prevent backflow, and opening the semilunar valves. blood flows into the arteries.
describe what happens during cardiac diastole
the heart is relaxed. blood enters the atria, increasing the pressure and pushing open he atrioventricular valves. this allows blood to flow into the ventricles. pressure in the heart is lower than in the arteries so semilunar valves remain closed