eukaryotic cells Flashcards
what is a eukaryotic cell?
a cell which contains a nucleus and other membrane bound organelles
- makes up multicellular organisms
describe the structure of the nucleus
- nuclear pores allow movement of molecules eg mRNA
- double membrane called nuclear envelope
describe the function of the nucleus
- contains genetic info (DNA) which directs protein synthesis
- DNA associates with histone proteins to form chromatin which prevents the DNA getting tangled
- controls metabolic processes
describe the nucleolus
- within nucleus
- produces ribosomes
- made of proteins and RNA
describe the structure of mitochondria
- double membrane
- inner membrane folded to form cristae
- fluid interior = matrix
- contains mitochondrial DNA
describe the function of mitochondria
- respiration occurs
- energy is stored in bonds of organic molecules
- cristae has an increased surface area for respiration
- contains enzymes
- produces ATP
describe the structure and function of vesicles
- membranous sacs for storage and transport made of phospholipid bilayer
- contains fluid
describe the structure and function of lysosomes
- specialised vesicles
- contains hydrolytic enzymes
- breaks down waste and pathogens
- important in immune system
state the 3 parts of the cytoskeleton
microfilaments
microtubules
intermediate fibres
describe the structure and function of the cytoskeleton (microfilaments)
- contractile fibres
- formed from actin protein
- movement and contraction during cytokinesis
describe the structure and function of the cytoskeleton (microtubules)
- globular tublin proteins
- polymerise to form tubes
- acts like scaffold structure
- holds shape and allows movement
- composes spindle fibres
describe the structure and function of the cytoskeleton (intermediate fibres)
- mechanical strength
- maintains integrity
summarise the function of the cytoskeleton
- mechanical strength
- allows movement of organelles
- holds shape
- important in composition of spindle fibres and cytokinesis
describe the structure of the endoplasmic reticulum
- network of membranes
- flattened sacs called cisternae
- connected to nucleus
describe the function of smooth endoplasmic reticulum
lipid and carbohydrate synthesis and storage