biology Flashcards
chemical symbol for glucose
C6H12O6
name three thing plants and animals need glucose for?
respiration, to make amino acid , to make fat
describe how you test for glucose
-place some of the food sample into.
a test tube, add water and mix
-add benedicts solution and mix
-put the tube in a water bath for a for
minute
-recordd the colour of the solution
what is the function of proteins in the human body?
growth + repair of body tissues, antibodies/white blood cells, enzymes, hormones
where in the human body is starch broken down?
small intestines, mouth
what is the function of an emulsifier?
mixes two liquids that are usually unmixable to form an emulsion
enzyme
proteins that act as biological catalysts by speeding up chemical reactions
active site
the part of an enzyme that a substrate binds to
product of the breakdown of carbohydrates:
smaller sugars (eg: glucose, maltose)
product of the breakdown of proteins?
amino acids
products of the breakdown of lipids
fatty acids & glycerol
structure of DNA:
-double helix
-nucleotides held together by hydrogen bonds between complimentary base pairs
what is a gene?
a small section of DNA on a chromosome
function of a gene
codes for a particular sequence of amino acids to make a specific protein
genome
the entire genetic material in an organism
what are chromosomes?
thin strands of DNA
how does DNA code for a protein?
(transcription)
transcription:
1. an enzyme called RNA polymerase attaches to the DNA (at a non
coding region)
2. the enzyme separates the DNA strands
3. the enzyme moves along the strand and adds rNA bases (same as DNA but uracil rather than thymine)
4. the nucleotides link together and form mRNA which leaves through the nucleus
5. the DNA strands join again
how does DNA code for a protein?
(translation)
mRNA arrives at the ribosome
2. the tRNA which has complementary anticodons lines up to make specific amino acid
3. the ribosomes move along and join the amino acids made from the tRNA together, a polypeptide chain is made
4. proteins are made from the polypeptide chains
some bacteria have an extra
layer on top of their cell walls, what if the name of that layer?
slime capsule
where does the genetic material of a prokaryotic cell exist?
loose in the cytoplasm (chromosomal)
what is the name of extra small DNA found in some prokaryotes?
plasmid
state a similarity between plant cells and bacteria cells
both have cell walle
diffusion
particles move from a high to low concentration
net movement
particles move in all directions but there is a net movement from high to low
three factors that affect the rate of diffusion
-temperature
-surface area
-concentration gradient
how does concentration difference affect the rate of diffusion?
a greater conc gradient quickens diffusion
how does a higher temperature result in faster diffusion?
energy of particles increase, movement get quicker
паmе a useful substance that diffuses into our cells:
glucose
three adaptions of exchange surfaces
large surface are, short diffusion distance, moist surfaces
osmosis
diffusion of water across a partially permeable membrane
what is an isotonic solution?
a solution with the same water concentration as inside the cell
what is a hypertonic solution?
a solution with higher concentration than in the cell, if cell is in a hypertone solution, water will leave the cell
what is a hypotonic solution?
a solution with lower concentration than in the cell, if cell is in hypotonic solution, water will enter the cell
what will happen to an animal cell if it is in a hypertonic solution?
it will shrivel and die
what will happen to an animal cell if it ir in a hypotonic solution?
the cell will swell and expand
what will happen to a plant sell of if it is in a hypertonic solution?
-the plant cell loses water + shrinks
-becomes flaccid
-membrane pulls away from cell walls
-plasmolysis occurs
what happens to a plant cell in an isotonic solution?
nothing, plant cell will be stable
what will happen to a plant cell if it is in a hypotonic solution?
the cell swells + becomes turgid (cell walls stop plant cell from burning)
what does plasmolysed mean?
plant cell shrinks
define active transport.
mover molecules against a concentration gradient (requires energy)
state one adaptation cells may have if they need to carry out active transport?
large surface area
