unit 1.2 - cell structure and organisation Flashcards
(34 cards)
what is a eukaryotic cell?
refers to cells that have a nucleus and membrane bound organelles
example of a eukaryotic cell?
plant and animal cells
Nucleus?
contains DNA which codes for or controls protein synthesis
Nucleus Pores
Allow the transport of mRNA and ribosomes out of the nucleus.
Nucelolus
synthesis rNA tRNA and ribosomes
Nuclear envelope
Separates the contents of the nucleus form the cytoplasm.
Chromatin
condenses before cell division to form chromsomes
Rough
Endoplasmic
Reticulum
Packaging and storing proteins. Producing transport vesicles
which merge to form the Golgi body.
Endoplasmic reticulum
ribosomes attached to it
Golgi body
Packaging proteins for secretion from the cell. Modification
of proteins
lysosomes
contains powerful digestive enzymes to break down worn out organelles or cells
centrioles
form the spindle during cell division. not present in higher plant cells
mitochondria
ATP synthesis by aerobic respiration
chloroplasts
Contain photosynthetic pigments which trap light energy for
photosynthesis.
Vacuole
Contains cell sap and stores solutes such as glucose. Swells
due to osmosis for turgidity.
Ribosomes
Protein synthesis. Primary protein structure is formed at the
ribosome.
Plasmodesmata
connects cells via cytoplasm filled canals which pass through cell walls.
cell surface membrane
absorption of amino acids
cell wall
protects the cell and keeps it upright
what are the similarities between mitochondria and chloroplasts?
Both have double membrane
Both have highly folded inner membranes
Both have a circle of DNA for self-replication
Both have ribosomes
Both produce ATP
what are the differences between mitochondria and chloroplasts?
Mitochondria have cristae, but chloroplasts have thylakoid membranes.
Chloroplasts contain photosynthetic pigments to absorb light energy, mitochondria
do not.
Mitochondria have an inner matrix, but chloroplasts have a stroma.
Prokaryotic cells?
don’t have membrane bound organelles in their cells - no nucleus, rough endoplasmic reticulum,golgi body,mitochondria or chloroplasts
compare eukaryotic and prokaryotic cells
prokaryotic cells =
small 1 -10 nanometres
ribosomes are smaller and free in cytoplasm
no membrane bound organelles
DNA = free in cytoplasm
no nuclear envelope
eukaryotic cells =
big 1 -100 nanometres
ribosomes = larger and bound to the rough endoplasmic reticulum
membrane bound organelles = present
DNA contained with the nucleus
nucleus has double membrane
why don’t viruses fit the cell theory?
they have no cell membrane, no cytoplasm, no
organelles and no chromosomes. and can only reproduce with the help of a host cell.