cell structure 3.2.1 Flashcards
function of the nucleus (3)
acts as the control centre through protein synthesis
retains genetic material
manufactures ribosomal RNA and ribosomes
what is the nuclear envelope
double membrane with ribosomes on surface that surrounds nucleus
function of the nuclear envelope (2)
controls entry and exit of materials
contains reactions
function of nuclear pores
allow passage of large molecules out of the nucleus
what is the nucleoplasm
granular jelly like material
what are chromosomes
consist of protein bound linear DNA
what is the nucleolus
small spherical region within the nucleoplasm
what is the function of the nucleolus
manufactures ribosomal RNA and assembles ribosomes
what is the function of the mitochondria (2)
site of aerobic respiration
produces ATP
function of the mitochondria double membrane
controls entry and exit of material
what are mitochondria cristae
extensions of the inner membrane
function of the mitochondria cristae
provide a large surface area for the attachment of enzymes
what is the mitochondria matrix
contains proteins, lipids, ribosomes, and DNA
what is the function of the mitochondria matrix
allows mitochondria to control the production of some of its own proteins
what are 3 adaptations of the chloroplasts
1 granal membranes - large surface area for attachment (of chlorophyll etc)
2 stroma fluid contains enzymes for making sugars
3 contains DNA and ribosomes to manufacture proteins quickly
what is the function of chloroplasts
to carry out photosynthesis
what is the chloroplast envelope
a double plasma membrane that surrounds the chloroplast
function of the chloroplast envelope
highly selective in what its allows to enter and leave
what are the grana (in chloroplasts)
stacks of thylakoids where light absorption takes place
what are thylakoids (in chloroplasts)
disc structures containing chlorophyll
what is the stroma (in chloroplasts)
fluid filled matrix containing starch grains
what is the function of the stroma (in chloroplasts)
where the synthesis of sugars takes place
what is the endoplasmic reticulum
3 dimensional system of membranes that is continuous with the outer nucleus membrane
encloses a network of tubules and cisternae
what does the rough ER have
ribosomes on outer surfaces of membranes
function of the rough ER (2)
1 provides a large surface area for the synthesis of proteins and glycoproteins
2 provides a pathway for the transport of materials, especially proteins, throughout the cell
how does the smooth ER differ from the rough ER
lacks ribosomes and is more tubular in appearance
function of the smooth ER (2)
1 synthesises stores and transports lipids
2 synthesises stores and transports carbohydrates
what is the Golgi apparatus
consists of cisternae and Golgi vesicles
how does the Golgi apparatus work
- modifies proteins
- sorts proteins and transports them to correct destinations
- proteins transported in Golgi vesicles
- vesicles may move to the cell surface where they fuse with the membrane and release contents to the outside
what are the functions of the Golgi apparatus (5)
1 add carbohydrate to proteins to form glycoproteins
2 produce secretory enzymes
3 secrete carbohydrates
4 transports, modifies and stores lipids
5 forms lysosomes
what are lysosomes
formed when Golgi vesicles contain enzymes and they contain lysozymes
what are lysozymes
enzymes that hydrolyse the cell wall of certain bacteria
what are the functions of lysosomes (4)
1 hydrolyse material ingested by phagocytic cells
2 release enzymes via exocytosis
3 digest worn out organelles
4 completely breakdown dead cells
what are ribosomes
small cytoplasmic granules made of two subunits (one big one small)
function of ribosomes (2)
contain ribosomal RNA and protein
site of protein synthesis
what kind of ribosomes in eukaryotic cells
80s
what kind of ribosomes in prokaryotic cells and mitochondria
70s (slightly smaller than 80s)
what is the cell wall
consists of a number of polysaccharides eg cellulose
what is the fungi cell wall made of
chitin
what is the algae cell wall made of
cellulose/glycoproteins
function of the cell wall (3)
1 provides mechanical strength to prevent cell bursting from osmotic pressure
2 mechanical strength provided to plant as a whole
3 allows water to pass along it
what is a vacuole
fluid filled sac bounded by a single membrane called a tonoplast
contains a solution of mineral salts, sugars, amino acids
function of vacuole (3)
- supports plants by making cells turgid
- sugars and amino acids act as a temporary food store
- pigments colour petals to attract pollinators
how do prokaryotic cells differ from eukaryotic cells
they are smaller and have no nucleus or nuclear envelope
what are the general parts of a prokaryotic cell (10)
cell wall
cell membrane
capsule
cytoplasm
meosome
pilli
nucleoid
plasmid
ribosomes (70s)
flagella
general parts of a virus
glycoproteins
lipid membrane
RNA
capsid
matrix
reverse transcriptase
capsule structure and function
outer layer
protects bacterium from other cells
nucleoid (circular DNA) structure and function
long strand
processes genetic information for replication of bacterial cells
plasmid structure and function
loop of DNA
carry genes for replication (involved in antibiotic resistance)
what are prokaryotic cell walls made of
murein
