key concepts in biology

biology - topic one

what are all living things made of?

cells

eukaryotic

organisms whose cells have a nucleus and organelles e.g plants and animals

prokaryotic

organisms without a nucleus e.g bacteria

nucleus

contains genetic material (arranged in chromosomes) and controls the cell

cytoplasm

gel-like substance where chemical reactions occur

cell membrane

controls what enters and leaves the cell

mitochondria

where respiration occurs

ribosomes

proteinsynthesis

cell wall

supports and protects the cell

chloroplasts

traps light for photosynthesis

plasmid dna

small loops of extra dna

subcellular structures in a bacterial cell

cell membrane, ribososmes, plasmid dna, flagellum

flagellum

long hair-like structure that rotates for movement

subcellular structures in a plant cell

nucleus, cytoplasm, ribosomes, mitochondria, cell wall, cell membrane, chloropast, vacuole

subcelular structures in an animal cell

nucleus, cytoplasm, mitochondria, ribosomes, cell membrane

light/ mirror

reflects light up to see specimen clearly

stage

where you place your slide

nosepiece

rotate to select objective lens

objective lens

lens you change for different magnifications

eyepiece lens

lens you look through

light microspcope

uses light to see large subcellular structures in colour, lower magnification and resolution

electron microscope

uses beams of electrons to see small subcellular structures in monochrome, higher magnification and resolution

sperm cell adaptations

haploid nucleus, acrosome/enzymes to burrow through egg cell, long tail to swim fast, mitochondria for energy

egg cell adaptations

haploid nucleus, nutrients in cytoplasm to have energy for growth and division, jelly layer around cell membrane to protect cell in oviduct, cell membrane hardens after fertilisation to prevent a second sperm cell

ciliated epithelial cell

lines oviduct to move egg cell from ovaries to uterus, hair-like extensions to sweep things from side to side across the surface

ciliated epithelial cell with microvilli

lines small intestine so food is absorbed into your body, finger-like extensions to increase surface area

enzymes

biological catalysts that break down large, insoluble molecules into smaller, soluble molecules

amylase

breaks down starch into sugars

protease

breaks down proteins into amino acids

lipase

lipids into fatty acids and glycerol

iodine for starch

turns blue/ black if present

biuret for proteins

turns purple if present

benedict’s for reducing sugars

turns green if present

ethanol and water for fats

get milky later if present

optimum

conditions where an enzyme works best

denatured

active site changes shape because temperature is too high or pH is wrong

osmosis

net movement of water molecules from a high concentration to slow concentration across a semi permeable membrane

active transport

the net movement of particles across the concentration gradient across a partially permeable membrane using energy

diffusion

movement of particles from a high concentration to a low concentration

calorimetry

clamp boiling onto stand, fill tube 20cm³ of water and record the temperature, weigh one of the foods and record the mass, use tongs to hold the tube after lighting it, when food has burnt rerecord waters temperature, repeat step with different foods