Cell structure and function Flashcards
what does a light microscope do?
It uses light passing through lenses to magnify an image
If the eyepiece lens is x10 and the objective lens is x40, what is the overall magnification
x400
do animals cells have a cell wall
no
do plant cells have a cell wall
yes
do animal cels have chloroplasts
no
do plant cels have chloroplasts
yes
describe the vacuoles in animal cells
temporary sell vacuoles present
describe the vacuoles in plants
large permanent vacuoles present
what do electron microscopes use instead of light
a beam of electrons
how are the electron beams focused onto specimens
using magnets
how much can an electron microscope multiply the specimens by
by more than 500,000 times
what do you call the structure of cells when using an electron microscope (2)
fine structure
ultra structure
what are all cell (plasma) membranes composed of
phospholipids and proteins
what are phospholipids
fat molecules with a phosphate attached to them
thickness of cell membranes
thin
how are the phospholipids in a cell membrane aligned
in a double layer, phospholipid bilayer
how are the proteins embedded in a cell membrane
completely or partially embedded and capable of movement
because of the continual changing of positions of the proteins, what is the model of the cell membrane called
the fluid - mosaic model
do phospholipids attract or repel water
they have water loving and water hating parts
outer surface of cell membrane
phosphate
inner part of cell membrane
lipid
3 functions of the cell membrane
shape and support
semi-permeable barrier
site for metabolic reactions
what is a semi-permeable membrane
a membrane that allows some things to pass through but not others
how are cell membranes sites for metabolic reactions
the proteins can act as enzymes
what are enzymes
biological catalysts that control chemical reactions in the cell
what is the cytoplasm
a watery gel in which organelles are suspended
5 organelles suspended in the cytoplasm
Nucleus Ribosomes Mitochondria Chloroplasts Vacuoles
Cytoplasm + organelles =
protoplasm
4 functions of the cytoplasm
supports the organelles
stores materials
chemical reactions can occur
stage one of respiration in cytosol
1 material stored in the cytoplasm
food
Largest cell organelle
the nucleus
what is the nucleus surrounded by
the nuclear membrane
what is in the nuclear membrane
pores
pores in the nuclear membrane
nuclear pores
function of nuclear pores
allow substances in and out of the nucleus
what is in the nucleus
chromatin
describe chromatin
thread like material
what is chromatin made up of
DNA and protein
1during cell division what happens to chromatin
it condenses to form chromosomes
function of the nuclear membrane
to enclose the nuclear contents and allow materials in and out through pores e.g. RNA
3 functions of the nucleus
controls all cell activities
contains DNA and genetic information
controls replication of DNA and nuclear division
what is the replication of DNA
the ability of DNA to make an exact copy of itself
What are ribosomes
very small organelle
what are ribosomes made of
RNA and protein
where are ribosomes found? 2
free in the cytoplasm and attached to membranes
function of ribosomes
to synthesise (make) proteins
singular of mitochondria
mitochondrion
shape of mitochondria
rod shape
what are mitochondria surrounded by
a double membrane
the double membrane sound mitochondria is similar to
the plasma membrane
outer membrane of mitochondria
smooth
inner membrane of mitochondria
folded
do mitochondria contain DNA
yes, a single loop of DNA
function of mitochondria
the site of respiration in the cell
respiration
the controlled release of energy from food in all living cells
3 structures found only in plant cells
Cell wall
Chloroplast
vacuole
what is the Cell wall made of
cellulose
how permeable is the Cell wall
fully permeable
describe the Cell wall
it is tough but flexible
what is the middle lamella
the region between adjacent plant cells
what cements the cells together that is found in the middle lamella
calcium pectate
3 functions of Cell wall
mechanical strength and support to cell (and plant)
gives the cell shape
prevents it from bursting due to the uptake of water
what are Chloroplasts surrounded by
a double membrane
what is inside Chloroplasts
a gel like stroma
function of storm inside chloroplasts
runs a system of membranes
how are membranes aligned in the Chloroplast
they are stacked in places to form the grana
what is present in the grana in a chloroplast
chlorophyll
starch
ribosomes
do Chloroplasts have DNA in them
yes, they have 1 loop of DNA
function of Chloroplast
photosynthesis
leucoplasts
colourless organelles similar to Chloroplasts and store food e.g.. starch in potatoes
what is the vacuole
a large sac filled with fluid called cell sap
what is the vacuole surrounded by?
a single membrane
function of vacuole
takes in water by osmosis
turgid cell
has its vacuole full of water
what are tugged cells important for
the support of the whole plant
osmosis
the diffusion of water through semi-permeable membrane
2 things that prokaryotic cells don’t have
no nuclear membrane
no membrane bound organelles (chloroplasts and mitochondria)
1 thing that prokaryotic cells have
ribosomes
example of prokaryotic cells
monera (bacteria)
3 things that eukaryotic cells have
a nuclear membrane
membrane bound organelles
ribosomes
which are bigger, prokaryotic or eukaryotic cells
eukaryotic cells
4 examples of eukaryotic cells
all fungi, protista, plant and animal cells
