1.2 cells Flashcards
what is a cell?
-basic unit of life
-small membrane bound structure containing several small structures called organelles.
what’s a eukaryotic cell?
any cell that has a nucleus
many membranous structures inside their cells. (organelles)
what cells don’t have a nucleus?
red blood cells/ phloem sieve tube cells
what is a nucleus?
largest organelle found inside animal cells and the second largest found in plant cells (after the vacuole)
function of nucleus
-contains DNA
-controls the activities of the cell
what are the 2 membranes that bound nucleus
nuclear envelope
nucleoplasms
nuclear envelope…..
why do they have pores/
outer membrance
- with pores to allow transport of mRNA and nucleotide
- outer membrane is continuous with E.R
function of the nuclear envelope
separates the contents of the nucleus from the cytoplasm
what does the nucleoplasm contain?
contains chromatin
what is chromatin
coils of DNA, bound to protein
function of chromatin
condenses into chromosomes during cell division
what does nucleolus do?
produces rRNA, tRNA and ribosomes
always stains darker
where is mitochondria found?
found in both animal and plant cell
function of mitochondria
site of ATP production during aerobic respiration
how is the golgi body formed?
formed from rough ER being pinched off at the end to form small vesicles. some join together to form the Golgi body
what do the vesicles that are pinched off the other end of the golgi body do
these secrete their contents via exocytosis when they fuse with the cell membrane
function of the golgi body?
what does it produce
-modifies/packages proteins to leave from the cell
-produces lysosomes (DE) and glycoproteins
-produced enzymes,
-transports and stores lipids
when are lysosomes produced?
produced when portions of the Golgi body pinch off
function of lysosomes
what do phagocytes use lysosomes for
-destroy worn out organelles in the cell
-digest material that has been taken into the cell
what are these digestive enzymes used for?
to destroy worn out organelles and to destroy foreign material
where are centrioles found?
what cells
found in animal cells and most protocists
describe the vacuole in an animal cell
small, temporary vesicles and may occur in large numbers
describe the vacuole in a plant cell
large and permanent fluid-filled sac bounded by a single membrane
what does a vacuole contain?
what is it surrounded by?
-sell sap
- surrounded by the tonoplast membrane
what does cellulose cell wall consist of?
is it permeable or non permeable?
cellulose microfibrils embedded in a polysaccharide matrix.
it is permeable
function of cellulose cell wall?
-provides strength/support
- transport of solutes
-cell to cell communication via the plasmodesmata
structure of a ribosome?
(made of?
found where)
1 large/1 small sub unit
made of ribosomal RNA and protein
found free or attached to the roughER
function of ribosome?
protein synthesis
What are ribosomes in eukaryotes?
80s
what does nuclear pores allow?
allow the transport of mRNA and ribosomes out of the nucleus.
structure of the endoplasmic recticulum?
2 types, rough ER: (covered with ribosomes and linked to the nuclear membrane )
smooth ER (no ribosomes)
both flattened into sacks cisternae
what is cisternae?
fluid-filled spaces between the membranes
function of the rough endoplasmic reticulum?
- transports proteins made by the ribosomes
function of the smooth ER
synthesise/transports lipids
what is the cell theory?
states that new cells are formed from other existing cells (mitosis) and that the cell is a fundamental in all living organisms
explain viruses……
-extremely small
- non cell (no cytoplasm/no chromosomes/no organelles)
- exist as an inert ‘viron’ when outside a cell
how do viruses work when in the body?
take over a cell’s metabolism & multiply within the host cell
what are viruses that attack bacteria ?
bacteriophagus
what does each virus particle have?
a core of nucleic acid surrounded by a protein coat called the capsid
what are the 3 types of muscle tissue?
-skeletal
-smooth
-cardiac
properties of skeletal muscle….
attached to the skeleton, capable of contracting and relaxing, voluntary control.
properties of cardiac muscle….
walls of the heart, appear striated (striped) and are under involuntary control
properties of smooth muscle …
l organs, except the heart,
spindle-shaped,
under involuntary control
properties of epithelial tissue
types of epithelial tissues
- nerve endings/ no blood vessels
-simple squarmous/simple cuboidal/ simple columnar ciliated
explain simple squarmous….
- single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm
-basement membrane
function of the simple squarmous…
allows passages of materials where protection isn’t important
location (squarmous)
line the Bowman’s capsule of the kidney
function of simple cuboidal
secretion and absorption
location of simple cuboidal
found in the kidney nephron and ducts of the secretory glands
simple cuboidal…..
single layer of cubelike cells with large, spherical central nuclei (on a basement membrane)
simple colimnar…….
-single layer of tall cells with round to oval nuclei
-cells have cillia if lining a tube which substrates move through
-known as ciliated columnar epithelial cells
location of simple colimnar
found lining the (cilia move mucus)
and the ovaries (cilia move the egg)
what is adipose tissue
fatty acid
properties of connective tissue
consists of…
in a …
consists of cells, elastic and collagen fibres in an extracellular matrix
function of connective tissues
tendons hold bone to bone
binds/supports tissues
what does adipose tissue equal
fatty acids
definition of an organ
a group of several different tissues working together to carry out a particular function for the whole organism
example of an organ
heart
definition of organ system
a group of organs working together with a particular role
example of organ system
digestive system
explain the structure of chloroplasts
double membrane
thylakoids, stroma and granum
what is stroma
the fluid found between the double membrane with ribosomrs/ lipids/ circular DNA and possible starch
what is thylakoids?
where photosynthesis takes place
often form coin-like stacks (grana) linked by lamelle
what is granum?
stack of thylakoids
why are thy thylakoids in stacks?
they mean bigger surface are for trapping light energy
function of chloroplast
contain photosynthesis pigments which trap light for photosynthesis
structure of plasmodesmata
microscopic channels whcih cross the cell walls of plant cells
explain the function of plasmodesmata
allows transport of materials and water
how do you get from mm to microns
x100
micros to mm
divide by 100
how do you work out the magnification of an image
image size/actual size
work out actual size
image size/magnification
similarities of mitochondria and chloroplasts
-double membrane
- 70s ribosomes for protein synthesis
- circular DNA
- highly folded inner membranes
- Fluid-filled
- both produce ATP
differences between mitochondria and chloroplasts
mitochondria- aerobic respiration, inner matrix, cristae
chloroplasts- photosynthesis, stroma, thylakoid membranes, thylakoids with chlorophyll to absorb light energy
what is cristae?
folds of inner membrane
what is a prokaryote cell
an organism that contains no membrane bound organelles
(nucleus)
what are the 2 types of prokaryote cells
bacteria
archaea
differences between prokaryote and eukaryote cells
(7 thing)
p- small cells, no membrane bound organelles, dna is free in the cytoplasms, no nucleus membranes or ER, smaller ribosomes, cell wall contains nurein
e- larger found in plant/animal/fungi/protoctists, membrane bound organelles, DNA on chromosomes, membrane bound nucleus, larger ribosomes, cell wall in plants made of cellulose
structure of the nucleus
dna is found here
contains the nucleolus(has ribosomes and rRNA
large round organelle surrounded by a double membrane.
(nuclear envelope)
contains nucleoplasm
what do nuclear pores do
allow the exchange of mayerials
what does mRNA contain
makes protein
structure of mitochondria
oval, double membrane (outer/inner)
inter membrane space
explain the inner membrane of the mitochondrial
highly folded into cristae which increases surface area for ATP synthesis
matrix is a viscous liquid which contains enzymes (inner membrane)
structure of the plasma membrane
2 layers of phospholipids embedded with proteins
function of the plasma membrane
regulates the movement of substances in and out of the cell
structure of the golgi body
flattened sacks (cisternae) with smaller vesicles around it. they punch off the end of the golgi body&can fuse with the plasma membrane
structure of lysosome
when does it form?
a sac containing digestive enzymes which can digest materials taken in by phagocytosis
form when small portions of the golgi body pinch off
why do the enzymes have to be kept away from the rest of the cell
they would destroy it
where are centrioles located
located outside the nucleus in the centrosome
function of the centrioles
makes the spindle fibres
structure of the cytoskeleton
fibrous network formed from/by different proteins of long chains of amino acids
function of cytoskeleton
major role in the movement of the cell and some cell organelles in the cytoplasm
where do plant cells gain their energy from
sunlight, cells in their leaves contain many chloroplasts
why are thylakoids green?
contain chlorophyll in the thylakoid membrane
structure of the cell wall
rigid layer that surrounds the cell membrane, made of cellulose (B glucose)
what are the pores in the cell wall called
plasmodesmata
function of the cell wall
provides support by keeping it rigid
stops the cell bursting
fully permeable, enabling water and other substances to pass through it
what does the plasmodesmata allow
the cytoplasm of neighbouring cells to connect
structure of the vacuole
large sac in the cytoplasm surrounded by a single membrane
consists cell dap
what’s the membrane around the vacuole
tonoplast
function of the vacuole
maintaining the cell in a turgid state which provides support to the plant
prokaryote structures are….
smaller less complicated
cell wall in prokaryote
made of peptidoglycon
not cellulose
plasma membrane in prokaryote
cell membrane that has an unfolding called the mesosome
not mitochondria, site of respiration in prokaryotes
ribosomes in prokaryotes
70s
DNA in prokaryote
no nucleus
DNA floats free in the cytoplasm, contain loops of DNA (plasmids)
Flagella in the prokaryote
aid with movement
function
capsule in prokaryote
stop the cell drying out or preventing phagocytosis by white blood cells
structure of the nucleus
large, round organelle with a double membrane
contains the nucleolus, which produces ribosomes and rRNA.
contains nucleoplasm ( DNA in the form of chromatin)
nuclear envelope contain nuclear pores
structure of the mitochondria
oval and have a double membrane
outer/ inter membrane space/ inner membrane (folded into cristae)
structure of the Golgi apparatus
a stack of flattened membrane bound sacks known as cisternae with smaller vesicles around it
