biology b1
cells
eukaryotes - made from complex cells - eukaryotic cells
animal and plant cells
prokaryotic- smaller and simplier cells called prokaryotic cells
bacteria
animal cells
nucleus - contains DNA in chromosomes, that controls the cells
cytoplasm - gel - like substances where most chemical reactions happen
mitochondrial - site of cellular respiration and contain enzymes needed for rections
cell membrane - holds cell together, controls what goes in and out. contain receptor molecules, used in cell communication
plant cell
nucleus
cytoplasm
mitochondria
cell membrane
ridged cell wall - made of cellulose, gives support
chloroplast - photosynthesis happens, contain green substance chlorophyll
bacteria cell -
chromosomal DNA - controls cell activity, floats free in cytoplasm. long strand in middle
plasmids -small loops of extra dan for things like drug resistance
cell membrane - controlls what goes in and out
how are they studdied
microscope - uses lenses to make them look bigger.
electron microscope
allow to see things in more. detail like internal structures of mitrocondria. allows us to have a much greater understanding of sub-cellular structures
microscopes
light microscope
eyepiece lense - look through to see image
objective lense - magnifies image, usually there are 3
stage - supports slide
clip - hold slide in place
handle - to carry
lamp - shines light through slide
focusing nobs - move stage up and down.
prep
take.a thin slice using tweezers, take a clean slide, use pipette to put 1 drop of water in middle to keep specimen in place, put specimen on slide. add drop of stain. place cover slip at one end holding it an angle, carefully lower and press down gently so no air bubbles
view
clip down onto stage, select lowest objective lens, use adjustment knobs, look through eyepiece until in focu and clear image, produce a scientific drawing
total magnification = eyepiece lens magnification x objective lens magnification.
DNA
contains genetic material
DNA is a double helix, made up of nucleotides joined together in long chains = polymers
base - a (adenine), c (cytosine), G (guanine) and T (thymine)
nucelotides
each nucleotide has the same sugar and phosphate group. the base is attached to the sugar
polymer
large complex molecules molecules composed of long chains of monomers joined together.
Respiration
transferring energy from the breakdown of glucose, happens in all living organisms - Its a universal chemical process
used to make ATP- stress the energy needed for many cell proccesses.
controlled by enzymes
affected by temp and Ph.
exothermic reaction
2 types, aerobic and anarobic
aerobic - plenty of oxygen needed, most efficient way way to transfer energy for gluscose
aerobic - glucose + oxygen ----- carbon dioxide + water
anaerobic - not the best way to transfer energy, transfers less energy per glucose molecule
glucose only partly broken down and lactic acid is produced
glucose ------ latin acid
plants and fungi - under certain conditions this may happen eg waterlogged soil, glucose --------- ethanol + carbon dioxide
photosynthesis
using sun as a source to make glucose, used to make larger molecules that the plants and algae need to grow, these make up the organisms biomas. this then works it way up the food chain,
happens inside chloroplast, which contains chlorophyll that absorbs light
happens in 2 stages, energy transferred by light is used to split water into oxygen gas and hydrogen ions. Carbon dioxide gas then combines with the hydrogen ions to make glucose.