a2.2- organelles Flashcards
cell wall function [2]
- maintains shape
- prevents bursting
prokaryotes
organisms that do not have a true nucleus
- dna not protected by the nucleus
plasma membrane
semi-permeable and selective barrier surrounding the cell
cytoplasm
internal fluid component of the cell
bound ribosomes
synthesises protein used outside the cells
free ribosomes
synthesises protein used inside the cell
rough er
starts folding of polypeptide
smooth er
synthesises the phospholipid
- used in cell membrane + cholesterol
cells with ERs
undertake secretory activities
mitochondria function
aerobic respiration
- requires higher concentration of oxygen and glucose
mitochondria structure
- double membrane
- inner membrane higher folded into internal cristae
golgi apparatus
- modifies polypeptides into their functional state
- sorts, concentrates and packs proteins into vesicles
- exocytosis
lysosome structure
membranous sacs filled with hydrolytic enzymes
lysosome function
- breakdown/hydrolysis of macromolecules
- contains lysozymes (digestive enzyme)
plasmids
autonomous circular DNA molecules that may be transferred between bacteria (horizontal gene transfer)
pili
hair like extensions that
1. enable adherence to surfaces (attachment pili)
2. mediate bacterial conjugation (sex pili)
slime capsule
thick polysaccharide layer used for protection against desiccation (drying out) and phagocytosis
vesicles
move substances in + out of cell
either to
1. within the cell (lysosomes)
2. plasma membrane out of cell
3. secretion to the outside of the cell (exostosis)
compartmentalised because [3]
- control concentration of chemicals needed
- avoid enzymes
- mRNA can be modified after transcription before it leaves the nucleus
typical cells contains [2 + reason]
- DNA as genetic material
- cytoplasm
- dissolve substances
- carry out metabolic reactions
prokaryote dna is..
naked + in a loop
eukaryote plasma membrane
enclosing a compartmentalised cytoplasm with 80S ribosomes
nucleus [5]
- with chromosomes made of DNA
- store genetic material as chromatin
- bound to histones
- contained in a double membrane with pores
- inner region called nucleolus: site of ribosome assembly
eukaryotes has cytoskeleton of…
microtubules and microfilaments
advantages of compartmentalisation in the cytoplasm
- concentration of metabolites and enzymes and the separation of incompatible biochemical processes
eg. lysosomes and phagocycotic vacuoles
plasma membrane composed of
lipids
structure of cytoskeleton
filamentous scaffolding within the cytoplasm
cytoskeleton function [2]
- provides internal structure
- mediates intracellular transport
less developed in prokaryotes
peroxisome function
catalyses breakdown of toxic substances and other metabolites
peroxisome structure
membranous sac containing a variety of catabolic enzymes
centrioles function
- microtubule organising centre
- arrangement of the mitotic spindle during cell division
- serve as anchor points for microtubules in the cytoplasm, cilia and flagella
centriole structure
- paired cylindrical
-shaped organelles composed of nine groups of three microtubules organised symmetry - fibrous protein inside the cells
chloroplast structure [2]
- double membrane
- internal stacks of membranous discs (thylakoids)
chloroplast function
site of photosynthesis- manufactured organic molecules are stored in various plastids
cell wall structure
- external outer covering made of cellulose
- not an organelle
cell wall function [2]
- provides support and mechanical strength
- prevents excess water uptake
plastids present in
plants
cell wall present in
plants + fungi
how do plants and fungi differ [3]
- no chloroplasts
- diff cell wall material
- decomposers
centrioles present in
animals
cilia present in
animal + plant
flagella present in
animal + plant
vesicle’s journey
- formed in the rough ER
- received by Golgi apparatus
- Golgi apparatus forms vesicles that transport substances to membrane
y is cell wall not an organelle
dont have a specific metabolic function
