| what are cells? | the basic building blocks of all living things |
| what are the two types of cells? | prokaryotes and eukaryotes |
| features of a eukaryotic cell | nucleus
nucleolus
ribosomes
rough endoplasmic reticulum (rER)
smooth endoplasmic reticulum (sER)
mitochondria
centrioles
lysosomes
Golgi apparatus
cytoplasm |
| nucleus | enclosed by two membranes with pores
contains chromosomes and a nucleolus
controls the synthesis of proteins |
| nucleolus | where ribosomes are made |
| function of ribosomes | site of protein synthesis
can be free floating or attached to the endoplasmic reticulum |
| rough endoplasmic reticulum | membrane bound flattened sacs with ribosomes attached to the outer surface
modifies extracellular proteins |
| smooth endoplasmic reticulum | like rER but no ribosomes attached
makes lipids and steroids |
| mitochondria | site of aerobic respiration
contains its own DNA and inner membrane called cristae |
| centrioles | found in animal cells only
involved in the formation of spindle fibres during nuclear division
hollow cylinders made of microtubules arranged at 90° of each other |
| lysosomes | involved in the breakdown of waste materials
single membrane bound organelle full of digestive enzymes |
| Golgi apparatus | membrane bound flattened curved sacs
involved in the modification and packaging of extracellular proteins transported from the rER
also produces lysosomes |
| features of a prokaryotic cell | cell wall
capsule
plasmid
flagellum
pili
ribosomes
mesosomes
nucleoid
cytoplasm |
| cell wall in prokaryotes | made of peptidoglycan
provides support and strength to the cell |
| capsule | protective slime layer
retains moisture and adheres to surfaces |
| flagellum | tail-like structure that rotates to move the cell |
| pili | hair-like structures that attach to other bacterial cells to allow exchange of plasmids |
| mesosomes | infoldings of the inner membrane
may contain enzymes needed for respiration |
| nucleoid | contains circular DNA
controls the cellular activities and reproduction |
| cytoplasm | supports and suspends organelles
cellular respiration can also occur in the cytoplasm |
| differences between eukaryotes and prokaryotes | no nucleus in prokaryotes
larger ribosomes in eukaryotes
no pili/no plasmid/no mesosomes/no nucleoid in eukaryotes
no membrane bound organelles in prokaryotes
eukaryotes are larger |
