b1 cell biology Flashcards
differences between prokaryotes and eukaryotes
1) prokaryotes have a single loop of DNA called plasmids, whereas eukaryotes have a nucleus
2) prokaryotes are much smaller in size
3) prokaryotes have a bacterial cell wall, made from peptidogyclan
4) prokaryotes dont have chloroplasts or mitochondria
what do animal cells contain?
nucleus
mitochondria
ribosomes
cytopasm
cell membrane
what do plant cells contain?
nucleus
rigid cell wall
cell membrane
mitochondria
ribosomes
cytoplasm
vacuole
chloroplasts
function of nucleus?
controls genetic material and controls the activities of the cell
function of mitochondria?
where most of the reactions for aerobic respiration take place and providing energy for the rest of the cell
function of ribosomes?
where protein synthesis takes place, making proteins
function of the cell membrane?
hold the cell together and controls what goes in and out of the cell
function of the cytoplasm?
gel-like substance where most of the chemical reactions take place. also contains enzymes that control these chemical reactions
function of cell wall?
made of cellulose and supports the cell and strengthens it
function of vacuole?
contains cell sap, a weak solution of sugar and salts
function of chloroplasts?
where photosynthesis takes place, making food for the plant. also contains chlorophyll which absorb light energy
orders of magnitude?
10x bigger= 10^1
100x bigger= 10^2
1000x bigger= 10^3
10x smaller= 10^-1
how to estimate the area of a sub-cellular structure?
treat it as as a regular object and use the equation:
area= length x width
what is a tissue?
a layer of cells with a similar function
what is an organ?
a group of tissues working together to perform a similar function
what is an organ system?
a group of organs working together to perform a vital function
how are sperm cells adapted for its function?
1) long tail so the sperm can move to the ovum.
2) the acrosome is packed with digestive enzymes to eat through the top layer of the ovum
3) full of mitochondria to provide energy for the sperm cell to swim longer distances
how are nerve cells adapted for function?
1) long axons, enabling impulses to be carried through long distances
2) a lot of dendrites to branch connections and form other nerve cells
3) a lot of mitochondrian to supply energy to make neurotransmitters
4) myelin sheath to prevent electrical current from exiting the axon and to maximise electrical current transmission
how are muscle cells adapted for function?
1) proteins called myosin and actin which slide over one another so the muscles can contract
2) a lot of mitochondria for re respiration and contraction
3) contains glycogen for respiration
how are root hair cells adapted for its function?
1) large surface area, due to roots, for more osmosis
2) mitochondria to provide energy for active transport of minerals
how are xylem cells adapted for its function?
1) the lignin which causes the cell to die, they become hollow and are joined end-to-end to form a long tube that the mineral ions can flow through.
2) the lignin is deposited in spirals so the cells can withstand the water pressure
how are phloem cells adapted for its function?
1) cell walls form sieve plates when they break down, allowing movement of substances from cell-to-cell
what happens as an organism develops?
cells in the body differentiate to become different cells and to complete different functions
when do animal cells usually differentiate?
at an early stage
when do plant cells usually differentiate?
at any stage of their life