Cell structure

the function of the nuclear envelope

double membrane with nuclear pores to allow movment of mRNA

what is the nucleoplasm full of

chromatin

what occurs in the nuclolus

ribsome production

whats the function of the nucleus

controls the cells activities by controling transcription of DNA

structure of a smooth endoplasmic reticulum?

-tubular structure with spaces

function of the smooth endoplasmic reticulum

-involved in lipid synthesis

-processes carbohydrates and lipids

-stores carbohydrates

why are smooth endoplasmic reticulums smooth

because it doesnt contain ribosomes

whats the structure of the rough endoplasmic reticulum

-series of interconnected flattened sacs

what are the dark blobs on the rough endoplasmic reticulum

attached ribsomes

function of the rough endoplasmic reticulum

its involved in the folding and processing of protein

golgi apparatus function

takes protein and lipids to process and package them- this includes lysosomes

a feature of mitocondria

double membrane

function of mitocondria

produces ATP during aerobic respiration

what are the folds in mitocondria called

cristae

what is found in cristae

respiration enzymes

what happens to processed molecules

they bud off in vesicles

function of ribsomes

site of protein synthesis + translates mRNA into proteins

function of centrioles

ensure accurate seperation of chromosones during cell division and create spindle fibers

what are Lysosomes

spherical sacs containing digestive enzymes

what is the function of lysosomes

involved in the breakdown invading cells/foreign material or worn down parts of cells

function of cell wall

offers support and strenght

whats the cell wall made of

—cellouse in plants

-chitin in fungi

functions of permanent vacule

-stores cell sap

-helps mentain cell pressure and structure

what are chloroplasts made of

-double membrane

-thylakoids

-grana

-intergranal lamellae

-storma

-DNA and ribsomes

what is the function of a double membrane in chloroplasts

controls movment of substances into and out of the organelle

what are thylakoids

fluid filled sac like membranes that contain chlorophill, electrons transport chains and ATP synthase

what are thylakoids the site of

light dependent reactions

what is grana

stacks of up to 100 thylakoids

what does stacking thylakoids do

increases surface area for light absorbtion and efficient electron transport

what is the intergranal Lamellae

tubular membrane extensions that connect seperate grana together

what is the stroma

it is the fluid filled matrix surrounding the grana which is the site of the light independent reaction

what does the stroma contain

enzymes, starch grains and lipid droplets

function of DNA and ribosomes

allows chroloplasts to quickly synthesise the specific protein and emzymes needed for photosynthesis

how much DNA and ribsosomes are found in chloroplasts

70s ribosomes and a circular strand of DNA

function of the cell wall

provides strenght and support

whats the cell wall made out of in plants

cellulose

what does the vacule store

cell sap

function of the permanent vacule

helps mentain cell pressure and structure

function of the capsule

prevents dessication and protects the cell from antibiotics and viruses

what are the ribosomes in prokaryotic cells like compared to the ones in eukaryotic cells

smaller (70s not 80s)

what do prokaryotic cells have instead of a nucleus

single strand DNA

what are plasmids

small loops of DNA which can be shared between cells

whats prokaryotic cell wall made out of

murein

whats the flagellum used for

locomotion

whats the function of a membrane infold

increases surface area for respiration or photosynthesis to take place

how are prokaryotes used in the food and argiculture industry

-fermented foods

-probiotics

-pesticides

how are prokaryotes used in the industrial and pharmaceuitical industry

-chemical manufacturing

-enzyme and protein production

-antibiotics

-steroid vaccine and insulin production

how are prokaryotes used for scientific research

-genetic engeneering

-biotechnology

what are the organelles in a eukaryotic cell like

membrane bound

what are the organelles in a prokaryotic cell like

not membrane bound

are virus cells prokaryotic or eurkaryotic

neither

features of virus

-are acellular (lacks cellular structure) non living particles- no organelles or cytoplasm

-1000 x smmaller than bacteria (20-300nm)

what do virus contain of

-RNA that is coated by a protein coat (capsid)

-may be enclosed in a lipid envelope

-capsid/lipid envelope has attachment antigens to help recognise a host

enviormrntal factors for virus:

-alcohol e.g wipes, hand gel

-detergents

-heat e.g. body temp

-enzymes e.g. enzymes

primary function of the capsid

-protect viral genome from damage by nucleases+ other enviormental factors within the host

capsids role in attachment

• contains attachment proteins that bind to specific receptors on surface of host cells - initiates infection process

the capsids role in entry

-aids in the entry of the virus into the host cell

the capsids role in genome delivery

facillitates the release of viral genetic material into the host cell

the capsids role in packaging

-responsible for packaging newly formed viral particles, this ensures they are infectious for future cycles

primary function of the envelope

attachment-

interacts with specific receptors on host cell,

innitiating the attachment progress

the envelopes role in the entry process

-it facilitates fusion of virus with host cells plasma membrane -allows the viral contents to enter the cell

the envelopes role in protection

• acts as a protective layer as it travels between host cells

the envelopes role in release

-viruses use cellular machinery to bud from host cell membrane - this aquires envelope during the release process

role of the envelope in host range and atigenicity

-specific viral protein determine which host species virus can infect +

how hosts system recognizes and respond to virus

what is the envelope fragille when exposed to

-heat, detergents + other agents that disturb lipids

-these make enveloped viruses less resistant to enviormental conditions

what types of nucleic acids can virus have

-DNA

-RNA

-never both

what do DNA viruses include

-double stranded and single stranded

what do RNA viruses include

single stranded and double stranded

what is double stranded genetic material

-like human DNA

-consists of two complimentary strands

what is single stranded genetic material

single strand of nucleotides

what is a linear shape of genetic material

a contineous chain of nucleotides

what is a circular shape of genetic material

the ends of the nucleic acid strand are joined

steps of how a virus invades a cell:

1- virus enters cell

2.substance in cell beggins to strip virus outer coat of protein

3.nucleic acid in center of virus is released

4.nucleic acid gets into cells chemical manifacturing system

5.cell makes new viruses instead of producing own chemical needs

6.cell sometimes destroyed in process which leads to many of new viruses being released and infecting other cells

how do attachment proteins work

act like “keys” to find coresponding “locks” (specific receptor proteins on the surface of a host cell)

what does the specific binding of attachment proteins ensure

that a virus can only infect certain cell types

what does the binding of attachment proteins trigger

changes that allow virus to penetrate cells membrane - leads to the release of its genetic material

how do we increase magnification

using a higher powered objective lense

what is magnification

how many times bigger a image appears

what is resolution

ability to determine between two separate points

total magnification formula

eyepiece lense magnificationn x objective lense magnification

magnification formula

image size/actual size

advantages of light microscope

-cheap

-can magnify living cells and small organisms

-easy to use

cons of light microscopes

-for specimens to be seen they must be thin

-can only magnify to 1500 and the resolution is 0.2 um (low)

electron microscope cons

--large

-very expensive

-cannot use live specimens

electron microscope pros

-shows us details of the insides of organelles

-have a higher magnification( to 2×10^6) and resolution (0.1nm)

what are the two types of electron microscope

transmission electron microscope

scanning electron microscope

how do transmition electron microscopes work

-very thin slices made and then stained with heavy metal

-electrons dont pass through heavily stained parts because electrons =absorbed

-those that do pass =focused by elecromagnets on a flourecent screen

advantages of transmission electron microscope

-lets us look in very high resolution at a thin section of a sample

-fast process

-particulary good for learning about how componets inside a cell are structured internally

how do scanning electron microscopes work

• specimens= coated with thin layer of metal e.g gold, platimum - improves conuctivity and contrast

• uses high focused beam of high energy electrons which reflect of the surface of structures

features of scanning electron microscopes

-gives 3d image- smples do not need to be thin

-specimin needs to be dead- it requires a vaccum as air particles would interfere with the beam of electrons

what is cell fragmentation

process where cells are broken up and different organelles they contain are seperated based on size/mass using gravity

3 stages of fermentation

-homogenisation

-filtration

-ultracentrifugation

what happens before cell fractionation begins

tissue is places in a cold ,isotonic buffer solution

why is the tissue placed in a cold solution

to reduce enzyme activity - bc it may break down organelles

why is the tissue placed in a isotonic buffer solution

prevent organelles bursting or shrinking due to osmosis

what does the first step of cell fractination homogenising include

-breaks up tissue to break open cell membranes + release organelles

what does the first step of cell fractination filtration include

homogenate is filtered to remove large debries - bc these are too heavy and sink at bottom of test tube

what does the first step of cell fractination ultracentrifugation include

• faster spinning = greater force

• at slower speeds = larger fragments collect at bottom - forms a pellet and smaller ones remain near the top suspended in a liquid called the supernatant

• each time supernatant is respun at a higher speed = some of smaller organelles collect at the bottom forming a new pellet

• method is repeated smaller organelles that will be recovered