OCR A-level Biology- cell structure

what is the definition for magnification

how much larger an image is than it’s actual size

what is the definiton of resolution

the ability to distinguish two adjacent points as separate from one another

what is an artefact

a visible structural detail cause by the processing of the specimen

what is an example of an artefact

an air bubble under the cover slip

what is the maximum magnification of a light microscope

x1500

what is the maximum resolution of a light microscope

200nm

what is the maximum magnification of a laser scanning confocal microscope

x2000

what is the maximum resolution of a laser scanning confocal microscope

similar to a light microscope

what is the maximum magnification of a transmission electron microscope

x5000000

what is the maximum resolution of a transmission electron microscope

0.1nm

what is the maximum magnification of a scanning electron microscope

x500000

what is the maximum resolution of a scanning electron microscope

1nm

what is an eyepiece graticule

a measuring device placed in the eyepiece of a microscope that acts as a ruler

what is a stage micrometer

a microscope slide with an accurate scale used to calibrate the value of eyepiece divisions at different magnifications

what is the equation for magnification

magnification = image size/actual size

what is the function of the golgi apparatus

to modify and package proteins and lipids into vesicles

what is the function of the nucleus

to store genetic information

what is the function of the nucleolus

to synthesise ribosomes

what is the function of the nuclear envelope

to protect the nucleus from the cytoplasm

what are the functions of the pores in the nuclear envelope

to allow the movement of substances into and out of the nucleus

what is the function of the smooth ER

to synthesise and store lipids

what is the function of the ribosomes

to be the site of protein synthesis

what is the cytoplasm composed of

the cytosol and organelles

what the function of the mitochondria

to be the site of aerobic/cellular respiration

what is the function of the rough ER

to synthesise and transport proteins

what does the rER contain

ribosomes

what are the centrioles composed of

microtubules and spindle fibres

what is the structure and function of lysosomes

they’re enzyme bound sacs containing hydrolytic enzymes

what is the structure of the smooth ER

flattened fluid filled membranes

what are the folds in the mitochondria called

cristae

what are the three components of the cytoskeleton

microfilaments, microtubules and intermediate filaments

what is the function of microfilaments

resist tension/maintain cell shape/aid the movement of organelles

what is the function of intermediate filaments

to anchor organelles

what is the function of microtubules

aids the movement of vesicles/forms spindle fibres

what is the cell wall of prokaryotes made of

peptidoglycan

what shape is prokaryotic DNA

circular

what ribosomes are present in prokaryotic cells

70s ribosomes

what ribosomes are present in eukaryotic cells

80s ribosomes

what is the cell wall in fungal cells made of

chitin

what is the cell wall in plants made up of

cellulose

what does endosymbiotic theory suggest

that eukaryotes evolved from prokaryotes by endosymbiosis

what is the role of the phospholipid bilayer

to control exchange of substances between the cell and it’s environment

what is the function of chloroplasts

they contain chlorophyll allowing photosynthesis to occur

what are the three main functions of the cytoskeleton

mechanical strength, aiding transport and enabling cell movement

how do prokaryotes reproduce

asexually by binary fission

why do we use stains in microscopy

to increase the contrast and distinguish between organelles

what does acetic orcein stain and what colour

stains chromosomes red

what does Eosin stain and what colour

stains the cytoplasm red

what does iodine stain and what colour

stains starch blue/black

what does iodine in potassium iodide stain and what colour

stains cellulose yellow

what does Haematoxylin stain and what colour

stains RNA/DNA purple/blue

what does methylene blue stain and what colour

stains DNA blue

what is differential staining

when each stain binds to a different cell structure