3.2.1 cellular biology Flashcards
what are cells?
the basic unit of structure and function in an organism
what is a eukaryotic cell?
have a true nucleus with a nuclear envelope surrounding the chromosomes and membrane bound organelle
what are examples of eukaryotic cells?
plant cells, animal cells, yeast and amoeba
what organelle are in a eukaryotic cell?
golgi apparatus, vesicles, rough endoplasmic reticulum, nucleus, nuclear envelope, nucleolus, nucleoplasm, cytoplasm, plasma membrane, mitochondria, ribosomes, smooth endoplasmic reticulum
what is the structure of the nucleus?
surrounded by a double membrane nuclear envelope, nuclear pores allow large molecules to pass through, nucleoplasm, nucleolus, chromosomes
what is the function of the nucleus?
controls the activity of the cell and stores DNA, the nucleolus produces RNA
what is the structure of ribosomes?
two sub units, one small, one large, contain ribosomal RNA and protein. 80S are only found in eukaryotes, 70S are found in prokaryotes, eukaryotes and chloroplasts
what is the function of ribosomes?
the site of protein synthesis
what is the structure of the mitochondria?
bound by a double membrane, outer membrane is the matrix, inner membrane is the cristae, has its own strand of DNA
what is the function of the mitochondria?
where aerobic respiration occurs, production of ATP
what is the structure of the cell membrane?
permeable to some substances but not to others
what is the function of the cell membrane?
controls the movement of substances in and out of the cell
what is the structure of the rough endoplasmic reticulum (RER)?
ribosomes present, connected to the outer nuclear membrane
what is the function of the RER?
protein synthesis, pathway for transport of materials out of the cell, motorway of the cell
what is the structure of the golgi apparatus?
stack of membranes, flattened sacs, contain small hollow structures called vesicles
what is the function of the golgi apparatus?
transport, modify and store proteins and lipids, transported by vesicles, produce lysosomes and secretory enzymes, the post office of the cell
what is the structure of the smooth endoplasmic reticulum (SER)?
no ribosomes
what is the function of the SER?
synthesise, store and transport lipids and carbohydrates
what is the structure of the cytoplasm?
a jelly like substance that contains dissolved nutrients and salts, organelle are suspended here
what is the function of the cytoplasm?
where most of the chemical reactions happen in the cell
what is the structure of the lysosome?
membrane containing up to 50 enzymes, vesicles produced by the golgi contain useful enzymes
what is the function of the lysosome?
garbage disposal, remove unwanted material, contain digestive enzymes to break down waste
what is the structure of a chloroplast?
outer membrane, inner membrane, thylakoid (stacks of grana), stroma (space)
what is the function of a chloroplast?
absorb the light energy required for photosynthesis,thylakoid stacks increase the surface area for light to hit, stroma allow gases to move freely for diffusion, double membrane reduces/controls diffusion
what is the structure of the permanent vacuole?
filled with cell sap
what is the function of the permanent vacuole?
helps keep the cell turgid
what is the structure of the cell wall?
made from cellulose fibres
what is the function of the cell wall?
strengthens the cell and supports the plant
what is a virus?
a microscopic intracellular parasitic organism that infects other organisms it is not a prokaryote or eukaryote
what is a parasite?
an organism that relies on a host for survival to the detriment of the host
what is the structure of a virus?
protein coat, nucleic acid, DNA/RNA, membrane envelope (some), tail (some), fibres, attachment proteins
what is nucleic acid? (virus)
RNA or DNA
what is a caspid? (virus)
protein coat that protects genetic material
what are attachment proteins? (virus)
attach to host
what is the membrane envelope? (virus)
an outer phospholipid membrane surrounding the caspid
what are the similarities between viruses and eukaryotes?
both have membrane envelopes made of phospholipid, both contain RNA or DNA
how will viruses hijack the hosts organelle?
enzymes for metabolic processes, mitochondria for energy/respiration, ribosomes for protein synthesis
why do viruses make you feel ill?
damage/cause cells to burst, take over organelle so the cell can’t work, attack the immune system
how do viruses attach to a cell?
The attachment proteins on the virus attach to the receptors, the proteins are complimentary to the receptors
How is the genetic material of viruses released into the cell?
The caspid fuses with the membrane and they release the genetic material into the host, all genetic material incorporates with cell genetic material
how does the virus multiply?
it used the hosts organelle and multiplies all genetic material (caspid, DNA/RNA and proteins)
what is exocytosis?
the virus bursts the cell and enters the blood to spread around the body
what is magnification?
the act of process of enlarging the physical appearance or image is something, not altering physical size
what is resolution?
the minimum distance apart two objects can be in order to appear as separate items, can distinguish between two neighbouring objects clearer, increased detail seen
what is the source of light microscopes?
light
what is the magnification of light microscopes?
up to 1500x
what is the resolution of light microscopes?
poor
how do you prepare a sample for light microscopes?
sample is washed, a simple chemical stain is added, covered with a coverslip
how does a light microscope work?
light passes through it
what is the resulting image of a light microscope?
2D image, black and white
what are the disadvantages of light microscopes?
cannot see small cells, organelle or viruses
what is an SEM?
scanning electron microscope
what is the source of SEM?
electrons
what is the magnification of SEM?
x30,000
what is the resolution of SEM?
just 20nm apart
how do you prepare a sample for an SEM?
coat surface of specimen with gold in vacuum
how does an SEM work?
scan a beam of electrons across the specimen, this knocks electrons off the specimen, which are gathered in a cathode ray tube to form an image
what is the resulting image in an SEM?
3D image, coloured
what are the disadvantages of an SEM?
expensive
what does TEM stand for?
transmission electron microscopes
what is the source for TEM?
electrons
what is the magnification for TEM?
up to 10,000,000x
what is the resolution in TEM?
0.1nm apart
what is the sample preparation for TEM?
stain with heavy metal, must be in a vacuum
what is the resulting image of a TEM?
2D, black and white, more detailed image
what are the disadvantages of TEM?
expensive, cannot look at living things, must cut section, must be in a vacuum, preparation may create artefacts
how do TEM work?
a beam of electrons is fired through the specimen
how do you calculate magnification?
image size= actual size x magnification
how do you convert from km to m?
x1000
how do you concert from m to cm?
x100
how do you convert from cm to mm?
x10
how do you convert from millimetres (mm) to micrometers (um)?
x1000
how do you convert from micrometers (um) to nanometers (nm)?
x1000
how do you do a scientific drawing?
good use of space, clear, strong lines, label lines are straight, clearly written labels, scale bar if appropriate, lines touch the labelled structure, no unnecessary shading or colouring
what is a disadvantage of using a stage micrometer?
you can’t use another slide at the same time
state the difference between prokaryotes and eukaryotes
eukaryote cells have a membrane bound nucleus prokaryotes do not, prokaryotes are much smaller and only contain 70S ribosomes, eukaryote DNA associated with proteins called histones, prokaryotes have plasmids
what is the role of the golgi apparatus?
store, modify and transport lipids and proteins
name the type of electron microscope that required the sample to be stained i. heavy metal and produces black and white images
transmission electron microscope
state the three stages of the cell cycles
G1, synthesis and G2
name the process by which substances move from an area of high concentration to low concentration down the concentration gradient using intrinsic proteins
facilitated diffusion
how does a TEM focus?
using magnets
how does a light/optical microscope focus?
using glass lenses
what do the specimens have to be for TEM?
dead, dehydrated and thinner
what is meant by uncertainty?
the experimenter’s best estimate at how far an experimental quantity might be from the true value
what effects uncertainty?
resolution, manufacturer’s tolerance, experimenter judgement, repeats, the size of increments
describe how to observe cells in a prepared slide using a light microscope
clip the slide onto the stage, select the lowest powered objective lens, use the course adjustment knob to bring the stage up to just below the objective lens, look down the eyepiece and use the course adjustment knob to move the stage down until the image is roughly in focus, adjust the focus with the fine adjustment knob until you get a clear image of what’s on the slide, if a greater magnification is required, refocus using a higher powered objective lens
what is the function of the matrix in mitochondria?
contains the enzymes needed for respiration
what is the function of the cristae?
Crista is a fold of the inner membrane to provide a spacious area for enzymatic reactions
