cell biology Flashcards
prokaryote
a prokaryotic cell (without nucleus)
a single-celled organism - unicellular
another word for prokaryote + example
unicellular organism i.e bacterium
eukaryote
organisms made up of eukaryotic cells with genetic material enclosed in the nucleus
5 subcellular structures in animal cells and what they do
nucleus - contains genetic material/ controls activity of cell
cytoplasm - a gel-like substance containing
enzymes where chemical reactions take place
cell membrane - holds cell together and controls what goes in and out
mitochondria - the energy source of the cell where most chemical reactions take place
ribosomes - where protein synthesis takes place
3 subcellular structures only in plant cells and what they do
- cell wall - made of cellulose supports and strengthens cell
- permanent vacuole - contains cell sap
- chloroplasts - contains a green pigment called chlorophyll that absorbs light needed for photosynthesis
what subcellular structures do bacterium contain and what do they do
cell wall - made of cellulose supports and strengthens cell
cytoplasm - a gel-like substance containing
enzymes where chemical reactions take place
cell membrane - holds cell together and controls what goes in and out
singular strand of DNA that floats freely around the cytoplasm
one or more small rings of DNA called plasmids - give antibacterial resistance
plasmids
one or more small rings of DNA that give antibacterial resistance found in bacteria cells
cell membrane
cell membrane - holds cell together and controls what goes in and out found in all cells
cytoplasm
cytoplasm - a gel-like substance containing
enzymes where chemical reactions take place found in all cells
cell wall
cell wall - made of cellulose supports and strengthens cell , found in bacteria and plant cells
chloroplast
chloroplasts - contains a green pigment called chlorophyll that absorbs light needed for photosynthesis found in plant cells
permanent vacuole
- permanent vacuole - contains cell sap
nucleus
nucleus - contains genetic material/ controls activity of cell
cytoplasm
cytoplasm - a gel-like substance containing
enzymes where chemical reactions take place
mitochondria
mitochondria - the energy source of the cell where most chemical reactions take place
4 differences between prokaryotes and eukaryotes
prokaryotes
- smaller in comparison
- cell division via binary fission
- always unicellular
- genetic material in single dna loop and plasmids
eukaryotes
- larger in comparison
- cell division via mitosis or meiosis
- often multicellular but sometimes unicellular
- genetic material enclosed in nucleus and no plasmids
equipment for microscopy practical (hint-9)
- small piece of onion or otherwise specified organism
- knife or scalpel
- a white tile
- forceps
- a microscope slide
- a coverslip
- a microscope
- iodine
- pippette
how many pieces of equipment are needed for the microscopy practical
9
microscopy practical preparation stage/ set up: (steps 1-6/7)
- 1 put one drop of water on the microscope slide using the pippette
- 2 separate a layer of the onion
- 3 peel a thin layer of epidermal tissue from the surface
- 4 use forceps to put it on the drop of water on the microscope slide
- 5 ensure the layer of onion cells is flat on the slide
- 6 put to drops of iodine on
- 7 carefully lower the coverslip onto the slide
microscopy practical method (steps 9-15)
- 9/1 select the lower power objective lense
- 10/2 move the stage as close to the objective as possible
- 11/3 place the prepared slide on the stage
- 12/4 focus away from the slide, using the coarse adjustment , until the specimen is in focus
- 13/5 move the high power objective in line with the slide
- 14/6 use the fine focusing adjustment to bring the specimen back into focus
- 15/7if the specimen cannot be brought back into focus, refocus under low power and repeat stages 5-6
2 risks of microscopy practical
- iodine could cause skin irritation
- iodine could cause eye irritation
what could be done to avoid skin irritation (microscopy rp)
- avoid contact with skin or wear gloves
- wash hands after handling bottle or slide
what could be done to avoid eye irritation (microscopy rp)
- wear safety goggles
microscopy practical steps - how would you put the coverslip on the slide
(carefully lower the coverslip onto the slide)
- place one edge of the coverslip on the slide
- then use a mounted needle to lower the other edge onto the slide
how do you go from a cm to a mm
x10
how do you go from mm to cm
divide by 10
how do you go from mm to um
x 1000
um to mm
divide by 1000
how do you go from um to nm
x 1000
how do you go from nm to um
divide by 1000
when do animal cells differentiate
in early stages of development
when do plant cells differentiate
throughout their life cycle
function of sperm cells
to fertilise egg cells for reproduction
3 adaptations of sperm cells
- Streamlined with a long tail to swim to the egg.
- Acrosome in the head containing enzymes to
digest the egg cell membrane. - Large number of mitochondria to release energy for movement.
3 adaptations of nerve cells
- Long to carry signals long distances.
- Branched connections to connect to other nerve
cells and form a network around the body. - Insulating sheath to enhance transmission of
electrical signals.
2 adaptations of muscle cells
- Contain a large number of mitochondria to
release energy from respiration for movement. - Long so that there is enough space to contract.
function of nerve cells
to carry electrical signals around the body
function of muscle cells
to contract for movement
2 adaptation of root hair cells
- Hair like projections to increase the surface area.
- no chloroplasts this is because they do not need them as they are in the soil
function of root hair cells
to absorb water and minerals from the soil
function of xylem cells
to carry water and minerals inside of plants
function of phloem
to carry glucose around the plant
3 adaptations of xylem cells
- Form hollow xylem tubes made of dead tissue.
- Long cells with walls toughened by lignin.
- Water and minerals flow from the roots towards the leaves only in one direction in a process called
TRANSPIRATION
3 adaptations of phloem cells
- Form phloem tubes made of living tissue.
- Cells have end plates with holes in them.
- Glucose in solution moves from the leaves to growth and storage tissues in a process called
TRANSLOCATION - two way movement
how do cells become specialised
As a cell differentiates it acquires different sub-cellular
structures to enable it to carry out a certain function. It has become a
specialised cell.
what is the main reason for cell division in mature animals
In mature animals, cell division is mainly restricted to repair and replacement.
how has the development of electron microscopes helped biologists to understand more subcellular structures
- An electron microscope has much higher magnification and resolving power than a light microscope.
- This means that it can be used tostudy cells in much finer detail.
- This has enabled biologists to see and
understand many more sub-cellular structure
magnification formula
size of image
——————–
size of real object
what specific genetic material is in the nucleus
The nucleus of a cell contains chromosomes made of DNA molecules. Each chromosome carries a large number of genes
how are chromosomes usually found in body cells
In body cells the chromosomes are normally found in pairs