Studying cells Flashcards
eukaryotic definition
-nucleus
-membrane bound organelles
nucleus general structure and function
-contains DNA
-largest organelle
-double membrane called the nuclear membrane
-nuclear pores allow for the passage of molecules
-nucleolus where ribosomal RNA is made
-ribosome proteins are synthesised in the nucleus but assembled outside the nucleus
-contains chromatin made up of DNA coiled around histones
-chromatin super condensed to form chromosomes
mitochondrion
-site of ATP production by aerobic respiration
-double membrane
-inner membrane folded to form cristae SO high SA for attachment of ATP synthase enzymes
-matrix contains proteins,lipids,mitochondrial DNA and ribosomes
rough endoplasmic reticulum
-highly folded membranes
-80s ribosomes
-RER synthesises and. transports proteins throughout the cell
-membrane folded into flattened sacks called cisternae
-RER joined to nucleus
smooth endoplasmic reticulum
-recombines glycerol and fatty acids to make triglycerides.
-packages triglycerides into vesicles and transports them to the golgi apparatus
ribosomes
-site of protein synthesis
-two subunits of a ribosome are made of a combination of long strands of rRNA
-dotted with ribosomal proteins.
golgi apparatus
-sorts modifies and packages molecules
-golgi vesicles may be used to form lysosomes
-composed of flattened sacs of membranes
-sacs are fluid filled and pinch off smaller sacs (called vesicles) at their ends
lysosomes
-used to hydrolyse damages and worn out organelles
-single membrane
-contain a large number of hydrolytic enzymes which are lysozymes in an acid solution which must be kept separate from rest of cell contents to prevent them from digesting organelles.
cell surface membrane
-controls the passage of molecules in and out of the cell
-made up of phospholipids, specific transport proteins, and carbohydrates arranged into fluid mosaic model
microvilli
finger like projections of the cell membrane
increase the surface area
centrioles
-form a network of spindle fibres across the cell
-fibres pull apart chromosomes
structures in a plant cell
-cellulose cell wall
-chloroplasts present
-large central vacuole
-carbohydrates stored as starch
-has no centrioles
differences between plant vs animal
cell wall vs cellulose cell wall
chloroplasts present vs no chloroplasts
large central vacuole vs no large central vacuole
carbs stores as starch vs carbs stored as glycogen
has no centrioles vs has centrioles
chloroplasts structure
granum which has stacks of thylakoid
thylakoid membrane contains chlorophyll for photosynthesis
stroma where photosynthetic reactions occur
starch grains is the energy storage molecule in plants
DNA in plants
chloroplast DNA
ribosomes in plants
70s ribosomes to make enzymes needed for photosynthesis
function of chloroplasts
-absorbs light energy to converts it to chemical energy
-chemical energy is used to make carbohydrates from CO2 and H2O
cellulose cell wall
-very strong which limits the volume of water that can move into the cell and stops osmotic lysis
-wall is permeable to most molecules
-cell walls of adjacent cells separated by a thin layer called the middle lamella
-has plasmodesmata, these are gaps in the cell walls that connect cell cytoplasm together to allow the easy movement of water soluble molecules
bacterial cell characteristics
-do not have nuclei
-does not have membrane bound organelles
prokaryotic cell vs eukaryotic cell
-circular DNA vs linear DNA
-contains no membrane bound organelles vs membrane bound organelles
-no true nucleus DNA is free vs a nucleus DNA contained within nuclear membrane
-70s vs 80s ribosomes
-some have capsule vs do not have a capsule
-cell wall made of meurin vs made cellulose
viruses characteristics
-not cells as are not alive
-contains DNA or RNA
-protein coat called a capsid
-virus has attachment proteins
-lipid viral envelope
resolution definition
ability to distinguish 2 objects that are close together
relationship between wavelength and resolution
shorter the wavelength the better the resolution
how the student could have used an eyepiece graticule to determine the mean diameter of stomata
-measure each stomata using an eye piece graticule
-calibrate the eyepiece graticule against a stage micrometer
-take at least 5 measurements and calculate a mean (more measurements are more accurate)
TEM AO1
-pass through the specimen
-allows you to view organelles
-specimens fixed in resin and sliced extremely thin so must be dead
-specimens stained using heavy metals
-specimens must be in a vacuum so the specimen must be dead
SEM
-specimens are not sliced
-electrons are bounced off the surface off the specimen
-3D image
magnification equation
actual size= image size/magnification
cell fractionation and differential centrifuge steps
-tissue is homogenised in a blender
-ice cold to reduce the action of enzymes that would digest organelles
-isotonic so prevents osmosis of water so cell lysis does not occur
buffered-stop pH changes which could denature enzymes
-mixture is then filtered to remove any large pieces of tissues
-centrifuged at high speed
-large organelles removes into a pellet
-supernatant is removed and centrifuged a higher speed for a longer time
-process is repeated until desired can be observed via a microscope
