cell structure and organisation Flashcards
1
Q
mitochondria structure
A
- 5um long
- 2 membranes
- fluid filled intermembrane space, folded inwards = cristae
- circle of DNA
- matrix contains lipids, proteins, enzymes
- 70s ribosomes
- large SA:V
2
Q
mitochondria function
A
- ribosomes for protein synthesis
- DNA allows replication
- produces ATP for aerobic respiration
- enzymes for respiration
3
Q
ribosomes strucutre
A
- 70s = prokaryote, 80s = eukaryote
- 1 large, 1 small subunit
- assembled in nucleolus from rRNA and protein
- pass out into cytoplasm
4
Q
ribosomes function
A
- site of protein synthesis
- read mRNA sequence
- translate genetic code into amino acids which fold into proteins
5
Q
golgi body strucutre
A
- fluid filled, flattened sacs
- surrounded by vesicles
6
Q
features of mitochondria and their significance
A
- looped DNA = codes for essential proteins in respiration
- 70s ribosomes = translate DNA to produce proteins
- cristae (infoldings) = increase SA of inner membrane
7
Q
golgi body function
A
- modify, process, package proteins
- transport and store lipids
- produce secretory enzymes, e.g. lysosome
- secrete carbohydrase for plant cell walls
8
Q
lysosome structure
A
- small, temporary vesicles
- single membrane
- contain digestive enzymes
- pinch off golgi body
9
Q
lysosome function
A
- digestive enzymes breakdown / recycle cellular waste and unwanted material
10
Q
nucleolus structure
A
- spherical structure
11
Q
nucleolus function
A
- produces and assembles ribosomes
12
Q
nucleus structure
A
- double membrane form nuclear envelope
- pores allow large molecules to leave (mRNA, ribosomes)
- contains DNA
- contains nucleoplasm
- contains nucleolus
13
Q
what is nucleoplasm?
A
- granular material in the nucleus
- contains chromatin (coils of DNA)
14
Q
nucleus function
A
- controls and regulates activities of the cell
- contains cells genetic material
15
Q
chromatin structure
A
- chain of nucleosomes
- coils of DNA that condense into chromosomes
16
Q
chromatin function
A
- package DNA into the tight/small space of the nucleus
- condense into chromosomes during cell division
17
Q
plasmodesmata structure
A
- fine strands of cytoplasm
- extend through pores in plant cell walls
18
Q
plasmodesmata function
A
- facilitate movement of molecules between cells
- allow communication between cells
19
Q
endoplasmic reticulum strucutre
A
- double membrane
- flattened sacs with fluid filled spaces (the cristernae)
20
Q
rough er structure
A
- series of flattened sacs enclosed by a membrane
- ribosomes on the surface
21
Q
rough er function
A
- folds and processes proteins
22
Q
smooth er structure
A
- system of membrane bound sacs that lack ribosomes
23
Q
smooth er function
A
- synthesis and transport of lipids
24
Q
centrioles strucutre
A
- hollow cylinders
- rings of microtubules
- in animals and plant cells (absent in higher plants)
25
Q
centrioles function
A
- organise microtubules that make spindle fibres in cell division
26
Q
chloroplasts structure
A
- 2 membranes form chloroplast envelope
- fluid filled stroma contains photosynthesis products
- 70s ribosomes
- circular DNA
- chlorophyll found on flattened sacs, thylakoids
- stacks of thylakoids = grana
27
Q
chloroplast function
A
- can make proteins and self replicate
- contains photosynthetic pigment to capture sunlight and convert into energy
28
Q
vacuole structure
A
- large, permanent fluid filled sac
- bound by single membrane = tonoplast
- sap stores nutrients, water, chemicals
29
Q
vacuole function
A
- maintains pressure in plant cells
- supports plant cell walls
- prevents wilting