eukaryotic cells (cell structure) Flashcards
what is a eukaryotic cell (whats classed as a eukaryotic cell)
they are all living things: animals, plants, fungi, protoctists. (NOT VIRUSES) (these have no nucleus)
what do RBCs, phloem and xylem cells have in common
theyre all eukaryotic cells w no nucleus
why do RBCs, phloem, xylem cells have ni nucleus
as they matured their nucleus was lost, to make a greater volume available inside the cell to pack more Hb/sucrose/water.
what does MRSGREN stand for
MOVEMENT
RESPIRATION
SENSITIVITY
GROWTH
REPRODUCTION
EXCRETION
NUTRITION
WHY ARE VIRUSES NOT CONSIDERED TO BE ALIVE
they dont fulfil MRSGREN except reproduction (they invade the hosts cells and hijack that cells metabolic reactions to reproduce/clone). viruses do contain genetic info which can mutate and evolve
what is the cytoplasm for
this is where chemical reactions take place w enzymes involved (like anaerobic respiration)
what is the cell surface membrane/plasma membrane
its selectively permeable and allows some substances to pass through it but not all.
what is the nucleus
this is where the DNA is located. the cells activities are controlled from here b the genes. transcription occurs here.
what is the cellulose cell wall for
it keeps the cell shape and stops it from bursting
what is the large permanent vacuole for
its where cell sap is found. it maintains turgor pressure
what are ribosomes for
for protein synthesis
when looking at an animal cell down a light microscope what can you not see but you would be able to see if you looked down an electron microscope
ribosomes, rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, microtubule, nucleolus
when looking at a plant cell down a light microscope what can you not see but you would be able to see if you looked down an electron microscope
ribosomes, plasmodesmata, endoplasmic reticulum, chromatin, nucleolus
you need to be able to label an animal cell.
go on google and find an a animal cell to label
you need to be able to label a plant cell.
go on google and find an a animal cell to label
description and function of plasma membrane
this is the membrane found on the surface of animal cells. its mainly made of lipids +proteins. the lipids are phospholipids, they arrange into 2 layers - the phospholipid bilayer. proteins are embedded in the bilayer.
function - regulates the movement of substances into and out of the cell, which allows it to respond to chemicals like hormones
description and function of cell wall
a rigid structure that surrounds plant cells. mainly made of cellulose. the cellulose fibres are linear (unbranched) and are arranged in layers. there are lots of gaps between the fibres so its fully permeable
function - supports plant cells
description and function of nucleus
a large organelle surrounded by a nuclear envelope double membrane which contains many pores. the nucleus contains chromatin and often a nucleolus. in eukaryotic cells the DNA is wound around proteins called histones which stop the DNA becoming tangled.
function - controls the cells activities (by controlling the transcription of DNA). the pores allow substances to move between the nucleus and the cytoplasm.
description and function of ribosome
either floats free in cytoplasm or is attached to RER. made up of proteins and RNA. eukaryotic ribosomes are 80s in size.
FUNCTION - where proteins are made (protein synthesis)
description and function of rough endoplasmic reticulum
surface is covered w ribosomes.
function- folds +processes proteins that have been made at ribosomes.
what does the nucleolus do
it makes ribosomes
description and function of smooth endoplasmic reticulum
similar to RER, but w no ribosomes.
function - synthesises + processes lipids
description and function of vesicle
small fluid filled sac in cytoplasm surrounded by a membrane.
function - transports substances in and out of the cell and between organelles. some are formed by the golgi apparatus or the endoplasmic reticulum
description and function of Golgi apparatus
flattened sacs. vesicles are often seen at edges of the sacs.
function - processes +packages new lipids and proteins. also makes lysosomes.
description and function of lysosome
a round organelle surrounded by membrane, no clear internal structure.
function - contains digestive enzymes that break down bacteria. these are kept separate from cytoplasm by the surrounding membrane (compartmentalised) and can be used to digest invading cells or to break down worn out components of the cell
description and function of mitochondrion
has a double membrane (inner one folds to form cristae) inside is the matrix. which contains enzymes.
function - its the site of aerobic respiration. energy is released and ATP is made.
description and function of chloroplast
surrounded by a double membrane. has membranes inside called thylakoid membranes. these membranes stack up in some parts to form grana. grana are linked tg by lamellae.
function - where photosynthesis takes place.
description and function of centriole
small hollow cylinders, made of microtubules. found in animal cells, but only in some plant cells. part of the cytoskeleton.
function - involved w the separation of chromosomes during cell division.
description and function of cilia
small hair like structures found on surface membrane if some animal cells. they have an outer membrane and a ring of 9 pairs of protein microtubules inside, w a single pair of microtubules in the middle. part of the cytoskeleton.
function - the microtubules allow the cilia to move, this movement is used by the cell to move substances along the cell surface.
what is the folding of the inner membrane in the mitochondrion for
the folding increases the SA for the final part of aerobic respiration
description and function of flagellum
they’re like cilia but longer. are surrounded by plasma membrane. inside theyre like cilia too. 2 microtubules in the centre and 9 pairs around the edge.
function - the microtubules contract to make the flagellum move. used like motors to propel cells forward
what is lamellae
thin flat pieces of thylakoid membrane
what substances pass out of the pores in the nuclear envelope
ribosomes, mRNA
what substances pass into the nucleus via the pores in the nuclear envelope
steroid hormones.
