B1 - Cell Level Systems Flashcards
Examples of prokaryotes:
- Escherichia coli = cause food poisoning
- Streptococcus bacteria = cause sore throats
- Streptomyces bacteria = kills disease-causing bacteria (in soil)
Cell stains:
- methylene blue = animal cell nuclei
- iodine solution = plant cell nuclei
- crystal violet = bacterial cell walls
Types of electron microscopes:
- TEM = most magnified image, beam of electrons passed through sample & focused
- SEM = 3D image of surface, sends beam of electrons across surface, reflected electrons collected
Mm —> um —> nm
x 1000, x 1000
How many chromosomes do humans have
46 in each cell
Magnification equation
M = I/A
I = image A = actual
Enzymes
= biological catalysts, proteins that speed up reactions in body without being used up themselves
Describe the point of saturation in increasing substrate concentration in an enzyme controlled reaction:
- at certain point, all enzymes bound to substrate molecule = point of saturation, maximum rate of reaction
no increase will make a change in rate of reaction
What is ATP (adenine triphosphate) used for:
- movement, contract muscle cells
- warmth, (exothermic, transfers energy by heating)
- synthesis large molecules from smaller ones, make new cell material
Cellular respiration:
An exothermic chemical reaction that produces ATP
Why do mitochondria have folded inner membranes?
- to increase surface area, where specific enzymes that control each chemical reaction in cellular respiration are found
What cells need lots of mitochondria(for energy)
- muscle cells (transfer energy to contract muscles for movement)
- liver cells (carry out many reactions)
Fermentation word and symbol equation:
Glucose —> ethanol + carbon dioxide
C6H12O6 —> 2C2H5OH + 2CO2
Why may fermentation take place in plants
- no oxygen is available
Eg. In roots of plants in waterlogged soils
Anaerobic respiration word equation:
Glucose —> lactic acid
Metabolic rate:
= Speed at which chemical reactions in your cells transfer energy from its chemical stores in food
State the polymer, enzyme that breaks it down and monomers for digestion of carbohydrates and starch:
Where does this happen?
Carbohydrate molecule -(carbohydrase enzyme)-> sugar molecules
Starch -(amylase enzyme)-> glucose monomers
= in mouth & small intestine
State polymer, enzyme and monomer for digestion of proteins:
Where does this happen?
Protein -(protease enzyme)-> amino acid molecules
= inside stomach & small intestine
State polymer, enzyme and monomers for digestion of lipid molecules
Where does this happen?
Lipid molecules -(lipase enzyme)-> fatty acid molecules & glycerol molecules
= inside small intestine
what happens once food molecules are fully digested?
= absorbed into bloodstream, travel to cells that need them
Explain how the reactants of photosynthesis enter the plants:
- water: enters roots though soil through root hair cells, diffuses by osmosis
- carbon dioxide: diffuses from air into plant through stomata in leaf
Two stages for series of photosynthesis reactions:
Stage 1 (light dependent): energy transferred from light splits water molecules into oxygen gas & hydrogen ions
Stage 2(light independent): carbon dioxide gas combines with hydrogen ions to make glucose
Instrument for measuring light intensity:
= photometer
What happens to the glucose produced in respiration, what are the other molecules converted into?
- some used immediately in respiration
- fats & oils: food store & growth
- sucrose: stored in fruit
- starch: food store
- cellulose: form cell walls
- nitrogen = proteins: growth & repair
