2.1 Eukaryotic + Prokaryotic cell structure + function Flashcards
give three key properties of a light microscope
portable
cheap
x1500 magnification
give 5 key properties of an electron microscope
not portable expensive dead specimen only vacuum inside high magnification + resolution than a light microscope
define magnification
how many times bigger an object appears
define resolution
ability to distinguish between 2 points in an image.
a higher resolution results in a clearer image
what is the difference in membranes between eukaryotic cells and prokaryotic cells
eukaryotic cells have membrane-bound nuclei whereas prokaryotic cells do not
what are akaryotic cells
non-living organisms that are not cells e.g viruses
define what a tissue is and give four examples
specialised cells that carry out a particular function in the body
e.g epithelial, connective, muscle, nervous
define an organ and give three examples
a structure made up of several different types of tissues grouped together to carry out a particular function in the body
e.g liver, stomach and leaf
define an organ system and give two examples
a group of organs working together to carry out a particular function in the body
e.g digestive and nervous systems
give three functions of a biological membrane
compartmentalisation-keeps everything together
transport-selective barriers to allow entry and exit of substances
cell adhesion/recognition
describe the structure of a phospholipid bilayer
a bilayer of phospholipids with hydrophilic heads facing outwards and hydrophobic tails facing inwards. there are integral proteins, glycoproteins, and glycolipids embedded into the bilayer
give the function of an integral protein
main transport system, forming permanent pores or carrier proteins
give the function of peripheral proteins
may be enzymes, involved in regulating transport
e.g cell signalling
give the function of glycoproteins
often act as antigens, important for cell recognition or hormone receptors
function of Golgi apparatus
modifies proteins
packages proteins
mucus and lysosome production
function of vesicles
takes molecules made by the Golgi apparatus and sends them out of the cell
function of ribosome
translation in polypeptide synthesis
function of lysosome
contains hydrolytic enzymes - involved in cell death and immunity
function of nucleolus
contains protein and RNA
function of chromatin (DNA)
template for protein synthesis
function of nuclear pore
mRNA leaves via pore after transcription
function of rough endoplasmic reticulum
production and transport of polypeptide/proteins
function of centrioles
involved in cell division (mitosis and meiosis)
function of mitochondria
aerobic respiration to produce ATP
function of smooth endoplasmic reticulum
synthesises steroids and lipids
what are the key features and functions of the mitochondrion
contains:
outer membrane
inner membrane
inter membrane space
matrix (viscous fluid with enzymes)
crista-increases surface area + is the site of ATP production
ribosomes - involved in protein synthesis
loop of DNA - polypeptide synthesis and self-replication
why are mitochondria different shapes and sizes
because they are cut at different angles
describe the production and transport of protein in cells
- DNA is transcribed to produce a strand of mRNA
- mRNA travels via nuclear pore to rough E.R
- mRNA is translated at ribosome to produce a polypeptide that folds into secondary and tertiary structure
- vesicle ‘pinches’ off rough E.R containing protein
- vesicle travels to the Golgi apparatus and fuses with it
- Golgi apparatus modifies and packages the protein into a vesicle
- vesicle travels to cell membrane, fuses and releases contents via exocytosis
give two properties of the centrioles
comes in pairs
each centriole is a bundle of tubes
what is the cytoskeleton made up of
microfilaments and microtubules, which are made up of proteins
give three functions of the cytoskeleton
3D web
cell organisation
cell transport and movement
describe the key features of the chloroplast
contains: inner and outer membrane ribosomes granum/grana/thylakoid intergranal lamella loop of DNA stoma (liquid)
function of thylakoid disc
large surface area to absorb sunlight for photosynthesis
intergranal lamellae
connect the grana
loop of DNA
polypeptide synthesis and self-replication
what is the first layer of the plant cell to form
the middle lamella
give two features of the middle lamella
largely made of pectin (polysaccharide)
found between plant cells
give the equation for the formation of calcium pectate
pectin + calcium ions ——–> calcium pectate
-COOH + Ca 2+ ———> calcium pectate which strengthens cell wall
what is the primary cell wall made of and give an advantage of this
insoluble cellulose microfibrils
permeable to substances dissolved in water
give two substances that can be embedded in the cell wall to make it impermeable
suberin and lignin
what kind of ribosomes do bacterial cells contain
70S ribosomes
give four features of eukaryotic cells
contains membrane-bound nucleus
contains membrane-bound organelles
80S ribosomes
no plasmids or slime capsule
give four features of prokaryotic cells
no membrane-bound nucleus
no membrane-bound organelles
70S ribosomes
has plasmids and slime capsule
give three features of a bacterial cell wall
contents are hypertonic to solution surrounding them
prevents swelling + bursting -maintains shape
consists of a layer of peptidoglycan
what are pili and flagellae and how do they support bacteria cells
pili are protein projections used for attachment and sexual reproduction
flagellae are many stranded helices of flagellin protein which helps cell to move around
features of cell surface membranes
contains respiratory enzymes as they have no mitochondria
contain mesosomes- infoldings of cell membranes
features of plasmids
rings of DNA that are transferred via pili
codes for part of the bacterial phenotype
reproduces asexually
feature of the nucleoid
genetic material that is not membrane-bound
feature of 70S ribosomes
smaller than 80S ribosomes
subunits of 50S and 30S
involved in protein synthesis
what do all bacterial cell walls contain
peptidoglycan
what is the main difference between gram-positive and gram-negative cell walls
gram-positive
contains large layer of peptidoglycan containing teichoic acid followed by plasma membrane layer
gram-negative
has outer-membrane layer followed by a layer of peptidoglycan and then another layer of plasma membrane
describe a positive test for Gram-positive bacteria
-add crystal violet/iodine complex
it becomes trapped in thick peptidoglycan layer
-add alcohol
resists decolouring with alcohol
-add red safranin stain
does not pick up red colour and remains purple/blue colour
describe a positive test for Gram-negative bacteria
-add crystal/violet iodine complex
sits on lipopolysaccharide layer but is not trapped
-add alcohol
lipopolysaccharide layer dissolves so peptidoglycan layer is exposed-crystal violet washes off
-add red safranin stain
peptidoglycan takes up red stain and remains red colour
what are the two types of antibiotics and what do they do
bacteriocidal-kill bacteria
bacteriostatic-inhibit growth of bacteria
what are the sites of action that are different in prokaryotic cells to eukaryotic cells, that antibiotics usually target
cell membranes + cell walls
genetic material
enzymes
ribosomes
what are the four main bacteria shapes
cocci-spherical
bacilli- rod-shaped
spirilla- twisted or spiral shape
vibrios-comma shaped
what are obligate aerobes
organisms that need oxygen for respiration
what are facultative anaerobes
organisms that use oxygen if available but can respire without
what are obligate anaerobes
organisms that only respire in absence of oxygen and are killed by oxygen
