Cells Flashcards
What is cell theory
Unifying (universally accepted concept in biology)
Organelles found in eukaryotic cells
Cell surface membrane
Nucleus
Endoplasmic recticulum
Golgi apparatus and vesicles
Lysosomes
Mitochondria
Ribosomes
Plant only :
Vacuole
Chloroplasts
Cell wall
Cell surface mem struc
Constantly in motion (fluid mosaic)
W phospholipids, intrinsic and extrinsic protiens, glycolipids and glycoproteins and cholesterol embedded
Cell surface mem function
Regulates movement of substances In and out of cell
Has receptors which allow it to respond to chemicals like hormones
Nucleus struc
Has nuclear envelope (forms double mem)
Nuclear pores within mem
Has little circ protiens - chromatin
- dna combines with histones
One or more of structures = nucleolus
Nucleolus function
RNA production
Nucleus function
Contains chromosomes
Controls cells activities via controlling transcription
Has instructions to make protiens
Nuclear Pores function
Allow sub like mrna to move her nucleus and cytoplasm
Types Endoplasmic recticulum
RER / rough
SER / smooth
What is RER struc
System of folded membranes w ribosomes studded in cisternae
What is cisternae
Flattened sacs
RER function
Protien synthesis - folds and processes protiens that have been made at ribosomes
Describe how RER involved in production of enzymes (2)
Has ribosomes
To make protiens - enzymes are protiens
Describe how phospholipids are arranged in plasma mem
Bilayer
Hydrophobic fatty acid tails face in side
Polar hydrophilic head / phosphate group to outside
SER struc
System of folded membranes No
Ribosomes
SER function
Synthesis and processing lipids
golgi app
stack of flattended cisternae
folded mem makes cis
golgi app func
processes and packages new lipids and proteins
makes lysosomes
examples of golgi func
add carb and pro = glycoprotien
package things w a destination
golgi ves
they carry prod
stores lipids and proteins made by golgi app and transports them out of cell via cell surface mem
what are lysosomes prod by
golgi
lysosomes struc
round organelle
surronded by mem
lysosomes func
has digestive enzymes lysozymes that digest and hydrolyse pathogens
they undergo exocytosis
what is exocytosis
rel of lysozymes to the outside of cell to destroy material and digest organelles to re use
mitochondria structure
double mem
oval shaped
inner mem folded to form cristae
inside is matrix which has enzymes involved in respiration
ribosomes struc
small organelle floating free in cytoplasm or attached to RER
either 80s or 70s
no mem
made up of protiens and rna
rib func
site of pro syn
where are 80s and 70s rib found
80s - eukaryotic cells
70s - pro
vacuole struc
single mem called tonoplast
filled w fluid cell sap
found in cytoplasm
what is cell sap
weak sol of salt and sugar
vacuole function
maintain pressure inside cell
cell rigidity
stops plant wilting
chloropasts struc
flattend struc
double mem - one folded mem and one additional stack = thylackoid mem
these thylakoid mem can stack to form grana
grana are linked by lamellae
has stroma
what are lamellae
thin flat pieces of thylakoid mem
what is stroma
thick fluid - some photosynthesis occurs here
chloropast function
site of photosyn
some happens in stroma and some in grana
cell wall struc
rigid struc
cellulose - animals and plants
in fungi - made of chitin
bacteria - murein
cell wall func
supports cell prev it from changing shape
how to eukaryotic cells become specialised and process eg cell –> ….
via differentiation
cells -> tissue -> organs -> organ systems -> organisms
organelles in prokaryotic
no mem bound organelles
smaller 80s rib
flagellum
circ dna
plasmids
some have slime capsule
plasma mem
cell wall
plasma mem made up of …
func…
proteins and lipids
controls mov of sub in and out of cell
cell wall func …
made up of ….
gives cell strength and support
prev from changing shape
made of polymer murein
what is murein
glycoprotien
pro w carb attached
slime capsule
protects bac from immune system
plasmids
loops of dna not apart of main circ dna
contain genes for antibiotic res
not always present, some have lots
circ dna
no nuc
circ dna flows freely in cyto
not attached histone protein
flagellum
locomotion
not all pro have them
structures in virus
capsid
genetic mat (rna/dna)
attachment pro
capsid
protein coat
some viruses have lipid envelope w glycoproteins
attachment proteins
allow viruses to enter cell by attaching receptor to host cell
and inject genetic mat for replication
viruses are acellular and dont undergo cell division bc
after injecting nucleic acid
infected host cell replicates virus particles
1st step of protein trafficking
protien syn on ribosomes on RER
2nd step of protein trafficking
proteins into rer for transport
3rd step of pro trafficking
golgi buds into vescicles containing pro
4th step of pro trafficking
golgi collects modifes and transports pro to cell surface/vac
5th pro trafficking
pro travel other parts of cell in vesicles or vesicles fuse w cell mem to deposit its stuff outside of cell (exocytosis)
prokaryotic cells rep via …..
binary fission
1st step of binary fiss
circ dna and plasmids replicate
main dna loop on rep …
once
plasmids can be replaicted…
loads of times
2nd bin fiss
cell bigger
dna loops move to opposite poles of cell
3rd bin fiss
cytoplasm begins divide
new cell walls begin to form
4th bin fissio
cytoplasm splits
2 new daughter cells
each daughter cell has one copy of DNA but variable number of plasmids
how do viruses use host cells to replicate themsleves
their attachment pro bind to comp receptor on surface of host cell
why can viruses only infect one type of cell
diff viruses have different attachment protiens and thus req diff receptor pro on host cells
magnification
how much bigger an image is compared to real life
resolution
ability to distinguish bet 2 points
3 types of mic
optical mic
transmission electron mic
scanning e microscope
how does optical microscope work
light beam condensed via condenser lens
light passes through specimen where wavelengths are filtered
what does wavelength of light pass through to prod visible image
obj lens
then eye piece
max mag of optical
x1500
max res of optical
0.2 micrometres (um)
adv of light mic
can see live specimens
observe live processes eg mitosis
images in colur
Name two structures in a eukaryotic cell that cannot be identified using an optical
microscope.
Mitochondrion / ribosome / endoplasmic reticulum / lysosome / cell-surface
membrane.
what limits resolving power of optical mic
shortest wavelength of light visible
electron mic max mag and res
0.1nm
x 1,500,000
electron mic advamtage
higher mag and res
higher res bc
shorter wavlength of e-
how do TEM mic work
electromagnets to focus beam of e- transmitted through specimen
denser parts of specimen absorb more e- makes them look darker
e- have short wave length so give higher res
tem adv
high res
high mag
so can see internal struc
tem disad
only used thinly sliced specimens so e- can pass through
artefcts present
Complex staining method / complex / long preparation time; Image not in 3D / only 2D images produce
what are artefacts
made during cell prep
thing that arent acctually apart of the specimen
eg dust, air bubbles, fingerprints
how do scanning e microscopes work
prod 3d image bc e- work in a differnt way
e- bounce off specimen and are detected by multiple detectors
mag and res of sem
100 000 x
0.1nm
how do you convert bet units
metre
milmeter
micrometer
nanometer
picometer
as you go down x 1000
as you go up divide by 1000
steps of eukaryotic cell becoming specialised
cell, tissuse, organs, organ sys, organism
sub cellular struc in prokaryote
plasmid
sime capsule
pilus
flagella
plasma mem
ribosome
cytoplasm
plasmid
smaller seq dna struc
small circ struc
slime capsule
prevent dessication and chem attack
protect bacteria from drying out and from attack by cells of the immune system of the host organism
pilus
for attachment to other cells or surfaces
transfer of material betwen bacteria
plasma mem
exhange of substances w environment
ribosomes
protein synthesis
cytoplasm
site of chemical reactions
how do viruses work
are acellular
dont undergo cell div
following injection its nucleic acids the infected host cell replicates its virus particles
to calc image length
mesasure from longet point
convert units to whatever the scale bar is
Whatever you get multiply that length of scale bar given to find actual size
Round mag to 3sf
SEM VS TEM
explain how hiv affects production of antibodies when aids devlops in a person
- Less/no antibody produced;
- (Because HIV) destroys helper T cells;
- (So) few/no B cells activated / stimulated
OR
(So) few/no B cells undergo
mitosis/differentiate/form plasma cells;
outline role of organelles in production, transport and release of proteins from eukaryotic cells
- DNA in nucleus is code (for protein);
- Ribosomes/rough endoplasmic reticulum
produce (protein); - Mitochondria produce ATP (for protein
synthesis);
4 Golgi apparatus package/modify;
OR
Carbohydrate added/glycoprotein produced by
Golgi apparatus;
5 Vesicles transport
OR
Rough endoplasmic reticulum transports; - (Vesicles) fuse with cell(-surface) membrane;
describe and explain role of antibodies in stimulating phagcytosis
not including process of phagcytosis
- Bind to antigen
OR
Are markers; - (Antibodies) cause
clumping/agglutination
OR
Attract phagocytes;
the movement of substances across cell membranes is affected by membrane structure describe how
- Phospholipid (bilayer) allows
movement/diffusion of nonpolar/lipid-soluble substances; - Phospholipid (bilayer) prevents
movement/diffusion of polar/
charged/lipid-insoluble substances
OR
(Membrane) proteins allow
polar/charged substances to cross
the membrane/bilayer; - Carrier proteins allow active
transport; - Channel/carrier proteins allow
facilitated diffusion/co-transport; - Shape/charge of channel / carrier
determines which substances
move; - Number of channels/carriers
determines how much movement; - Membrane surface area
determines how much
diffusion/movement; - Cholesterol affects
fluidity/rigidity/permeability;
