2.1 cell structure Flashcards
list all the structures in an animal cell
- surface cell membrane
- mitochondria
- ribosomes 80s
- smooth ER
- rough ER
- centrioles
- cytoskeleton
- cytoplasm
- golgi appratus
- lysosome
- nucleolus
- nucelar pore
- nuclear envelope
- (flagella)
list all the structures in a plant cell
- surface cell membrane
- mitochondria
- ribosomes 80s
- smooth ER
- rough ER
- centrioles
- cytoskeleton
- cytoplasm
- golgi appratus
- lysosome
- nucleolus
- nucelar pore
- nuclear envelope
- cell wall
- vacuole
- chloroplast
list all the sturctures in a bascteria cell
- cell sruface membrane
- cell wall
- cytoplasm
- slimy capsule
- circular DNA
- ribosome 70s
- plasmids
- flagella
- pili
- infolding cell membrane
describe function/properties of cell wall
- rigid dturtcure that surroudn the cell
- in plants made of cellulose
- in bacteria made of murein/peptidoglycan
describe function/properties of cell membrane
- found on surface of animal cells, just inside plant and bacteria cells
- phospholipid bilayer
- regulates movement of subtances into and out of cell
- have receptor molecules which allow ot repond to chemicals
describe function/properties of mitochnodria
- usually oval-shaped
- have a double membrane - inner one folds to form cristae which increases sruafec area to increase rate of reactions
- inside is matrix which containes enzymes involved in respiration
- site of aerobic respiration where ATP is produced
- found in large numbers in cells that are very active ad require a lot fo energy eg. sperm
describe function/properties of ribosomes
- very small organells
- 80s in plant and animal
- 70s in bacteria cells
- eitehr float in cytoplasm or attached to rough ER
- made up of protiens and RNA
- not surrounded by membrane
- site of proteinsynthesis
describe function/properties of smooth ER
- system of membranes enclosing a fluid-filled space
- synthesise and process lipids and carbohydrates
describe function/properties of rough ER
- system of membranes enclosing a fluid-filled space
- covered in ribosomes
- synthesise and process proteins to the secondary, tertiary and quaternary structures that have been made at the ribosomes
describe function/properties of nucleolus
- most concentrated part of chromatin in the nucleus
describe function/properties of nuclear envelope
- double membrane surrounding the chromatin and nucleolus
describe function/properties of nuclear popres
- holes in the nuclear envelope which allow for mRNA to leave the nucleus to the ribosomes
describe function/properties of golgi appratus
- a group of fluid-filled membrane bound flagttened sacs
- vesciles are released at the edges carrying proteins and lipids out of the cell
- further processes, synthesisis and packages protiens andlipids
- has a trans face and cis face
describe function/properties of centriole
- small hollow cylider made of microtubules
- found in animal cells eg sperm in flagella and cillia
- involved with the seperation of chromosomes during cell division
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describe function/properties of cytoskeleton
describe function/properties of cytoplasm
- galetinous liquid inside cells
- site of chemical reactions
describe function/properties of vesicles
- small fluid filled sace in the cytoplasm surrounded by phospholid membrane
- transports subtances in and out of cell and between organells
- some formed by golig apparatus or the endoplasmic rectilium whilst oither formed at cell surface
describe function/properties of lysosome
- round organells surounded by a phsopholipid membrane with mo clear intenral structre
- contain digestuve enzymes to digest invading cells or to break down worn out component of cell
describe function/properties of chloroplast
- small flattened strctre found in plant cells
- surrounded by double membrane - membrane called thylakoid
- thylakoid stacks up on one another to form granae, linked by lamallae (thin long pieces of thylakoid membrane)
describe function/properties of circular DNA
- singular strand of circular DNA dformign a closed loop
- contaisn genetci information for bascteria cell
describe function/properties of plasmid
- small circular rings of NDA, contain genes that can be passed between cells using pilli
describe function/properties of pili
- used for attacgemtn to otehr cells or surfaces involved in sexual reproduction
- can transfer plasmids between cells
- introcellular communucation
describe function/properties of slimy capsule
- helps protect from drying out and from attacsk of other cellls of host organsim
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describe function/properties of infolding cell membrane
- increases surface area for chemical reactions
- eg. some bacteria cells have chloroplast so may increasing rate of photsynthesis
describe function/properties of flagellum
- long hair like strctures that rotate enabling the prokaryote to move
defintion of magnification
- the degree to which the size of an image is bigger than the real object
magnification =
image/actual
defintion of resolution
the smallest distance that two obejcts can be apart whilst appearign as two objects
info about ligth microscopes
- uses light
- used to look at living cells
- resolution - 0.2micrometers
- magnifcation - x1500
- stainign can be used to easily idtentify organelles
pros and cons of light microscopes
pro:
- Cheap
- Easy to use
- Can view living tissue
- can be used to view eukarytoic cells, nuceli prossibel mitochndria and chloroplast
cons:
- Maximum resolution of 0.2µm
- Maximum useful magnification about x1500 therefore can;t see smaller organlles than mitochondria
- 2D images only
why is staining used
- increases cotrast so that organells can be seen
- increases contrast so that different biologial molceuels can be seen
what stains are sued
- methylene blue - staisn DNA blue
- acetic orcein - stains DNA red
- iondine - bidns ot stracg turns blue black, and cell walls brown yellow
hwo to prepare a dry mount
- Solid specimens are viewed whole or cut
into very thin slices with a sharp blade - sectioning - The specimen placed on the centre of
the slide and a cover slip is placed over the sample - eg. hair, pollen, dust and insect parts can be viewed whole in this way
- muscle tissue or plants sectioned and viewed in this way
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how to prepare a slide
- dry mount
- wet mount
- squash slides
- smear slides
how to prepare a wet mount
- Specimens suspended in a liquid
such as water or an immersion oil - cover slip is placed on from an angle
- eg. aquatic samples and other living organisms can be viewed this way
how to prepare squash slides
- wet mount is first prepared, then
a lens tissue is used to gently press down the cover slip - Depending on the material, potential damage to a cover slip can be avoided by squashing the sample between two microscope slides
- good technique for soft samples. Care needs to be taken sp that the cover slip is not broken when being pressed
- eg. root tip squashes are used to
look at cell division
how to prepare smear slides
- edge of a slide is used to smear
the sample, creating a thin, even coating on another slide - A cover slip is then placed over the sample
- eg. sample of blood - good way to view the cells in the blood
info about transmtion electron microscope (TEM)
- used ot observe images of internal 2D structures
- resolution - 0.5nm
- magnification - x 2000000
stains used: - Methylene blue - stains DNA blue
- Acetic orcein - stains DNA red
- Iodine - binds to starch - blue/black and cell walls - brown/yellow
pros and cons of TEM
pros:
- Higher resolution than light
- Higher magnification than light and SEM
cons:
- Shows 2D images
- Black and white images
- Dead specimens
- Lengthy prcoess to produce thin specimens - can produce artefacts
- Very thin specimens
inf about scannign electron microscope (SEM)
- used ot observe images of external 3D strcture
- can be coloured in after
- resolution - 1-20 nm
- magnification - x500,000
pros and cons of SEM
pros:
- Higher resolution than light
- Higher magnification than light
- Can show 3D images
cons:
- Max resolution lower then TEM
- Black and white images
- dead specimens
cytoskelton
- Microfilaments - made of actin. Responsible for cell movement and cell contraction during cytokinesis (cell division).
- Microtubules - globular tubulin proteins polymerise to form scaffold across the cell to determine cell shape. They act as tracks for the movement of organelles around the cell and the spindle fibres, which are used in the segregation of chromosomes, are made of microtubules.
- Intermediate fibres - provide mechanical strength and help maintain integrity
