2. cells P1 Flashcards
describe the structure of the nucleus
surrounded by a nuclear envelope
nuclear pores allow substances to enter/exit
dense nucleolus made of proteins and RNA
describe the function of the nucleus
contains genetic code for each cell
site of transcription, mitosis
describe the structure and function of the cell membrane
‘fluid mosaic’ phospholipid bilayer with intrinsic and extrinsic proteins embedded
isolates cytoplasm from extracellular enviromment
selectively permeable to regulate transport of substances
describe the structure and function of the rough endoplasmic reticulum
sheets of folded membranes forming flattened sacs called cisternae
covered in many ribosomes for protein synthesis
describe the structure and function of the smooth ER
sheets of folded membranes forming flattened sacs called cisternae
lipid synthesis
describe the structure of the golgi apparatus
a group of fluid filled, membrane bound sacs called cisternae
vesicles made by it are seen at the edges
describe the function of the golgi apparatus
processes and packages proteins and lipids
modifies them ready for release
synthesises glycoproteins
describe the function of the golgi vesicles
stores lipids and proteins, transports them out of cell via cell membrane
describe the structure and function of a lysosome
small, round membrane bound organelle.
contains hydrolytic enzymes (lysozyme) which digests the contents of phagosome
describe the structure and function of a ribosome
very small organism
either floats free in cytoplasm or is attached to RER
made of proteins and RNA
not surrounded by a membrane
PROTEIN SYNTHESIS
describe the structure of a mitochondrion
surrounded by a double membrane, inner membrane folded to form cristae (site of ETC/ oxidative phosphorylation)
fluid matrix - contains mitochondrial DNA, respiratory enzymes, lipids, proteins
describe the function of the mitochondria
site of aerobic respiration and ATP synthesis
describe the structure of a chloroplast
thylakoids - flattened discs stack to form grana which contain photosystems with chlorophyll
lamellae - tubes attract thylakoids in adjacent grana.
stroma - fluid filled matrix
what’s the function of a chloroplast ?
site of photosynthesis
what’s the function of a chloroplast ?
site of photosynthesis
describe the structure of the cell wall
bacteria: made of polysaccharide murein
plants: made of cellulose microfibrils
fungi: chitin
describe the functions of the cell wall
mechanical strength and support
physical barrier against pathogens
describe the functions of the cell wall
mechanical strength and support
physical barrier against pathogens
describe the structure and function of the cell vacuole in plants
surrounded by a single membrane
tonoplast contains cell sap (mineral ions, water, enzymes etc)
absorbs and hydrolyses potentially harmful substances to detoxify cytoplasm
makes cell turgid and therefore provides support (prevents plants wilting)
contrast the structure of animal cells (A) and bacterial cells (B)
A has a nucleus, whereas B has free DNA
A has mitochondria, whereas B doesn’t
A has no cell wall, whereas B has a murein cell wall
A has larger ribosomes
A has no capsule whereas B has a capsule
A has DNA bound to histones, whereas B has DNA not associated with histones
name the 2 key differences between fungal and plant cells
fungal cell walls are made up of chitin rather than murein
fungal cells don’t have chloroplasts
name the 2 key differences between fungal and plant cells
fungal cell walls are made up of chitin rather than murein
fungal cells don’t have chloroplasts
explain some common cell adaptations
folded membrane or microvilli increase surface area e.g. for diffusion
many mitochondria- large amounts of ATP for active transport
walls one cell thick to reduce diffusion pathway
state the role of plasmids in prokaryotes
small ring of DNA that carries non-essential genes
can be exchanged between bacterial cells via conjugation
(not always present)