cell biology Flashcards
what do plant cells contain
cell membranes
nucleus
cytoplasm
mitochondria
ribosomes
cellulose cell wall
permanent vacuole
chloroplasts
what do animal cells have
cell membranes
nucleus
cytoplasm
mitochondria
ribosomes
what do plant cells have over animal cells
cellulose cell wall(doesnt allow water to enter)
permanent vacuole
chloroplasts
what do bacteria contain
cell wall
cell membrane
ribosomes
cytoplasm
circular strand of dna
plasmid
-some have flaggela to allow it to move
what are the important parts of a light microscope
eyepiece lens on the very top where we look
mirror above the base
stage above the mirror where the slide sits
3 objective lenses above the slide/stage
coarse adjusting knob which is the big knob
fine focusing knob which is the small one on the arm above the lenses along side coarse
how do these light microscopes work
light from room hits mirror and is reflected onto our object on stage passing through 1 objective lens then through eyepiece lens
how is the image we see larger than the object
the lenses spread out the light rays
what is magnification equation
image/object
what is the resolution
how detailed the image is
what are pros of light microscope
pros
small
easy to use
relatively cheap
cons
limited resolution of 0.2 micrometre
what are pros and cons of electron microscopes
cons
-very expensive
-hard to use
pros
-have resolution of 0.1nanometres
2000x better resolution better than light
-can study organelles
what are the units for measurements
km
m
mm
um -has little branch on left u
nm
each are 1000x smaller each time
what are 3 stages of the cell cycle
growth
mitosis
division
why cant animals of different species reproduce to have fertile offspring
diff species have different no of chromosomes
what are the steps for the cell cycle
Cellular growth - the cell gets larger and produces more sub-cellular structures, such as mitochondria and ribosomes.
DNA replication - chromosomes duplicate, so that each consists of 2 arms (copies).
More cell growth.
Mitosis - the DNA divides into two.
Cytokinesis - the cell divides into two.
what is binary fission
where prokaryotic cells divide into 2
a type of reproduction as they are unicellular
what are the stages of binary fission
grow
replicate genetic material
grows new cell wall
pulls apart and is finished
how do you work out the cells produced when you have the mean division time and original no of cells
og number of cells x 2 to the power of number of division cycles
is cell wall outer or inner
outer
Which three conditions do bacteria require for fast growth?
Temperature
Nutrient availability
Moisture
Oxygen
what are some aseptic techniques
Cleaning surfaces with disinfectant
Washing hands with antiseptic soap and warm water before handling microorganisms.
passing all instruments through bunsen burner, solutions, and mediums
what are common examples of specialised cells in animals
sperm
nerve
muscle
what are common examples of specialised cells in plants
root hair
phloem
xylem
function and sperm adaptations
half dna
lots of mitochondria
flagellum-to swim through uterus and fallopian tube
streamlined
digestive enzymes to break hole into egg
function and nerve cell adaptations
-to carry electrical signals fast from 1 body part to another
-long
-branched connections at the end to connect and form network with other nerve cells
function and muscle cell adaptations
function is to contact quickly
-long for space to contract
-lots of mitochondria
function and root hair cell adaptations
funtion is to absorb water and minerals
-long hairs to give it large sa
function and xylem and phloem cell adaptations
-transport food and water around body
-cells long joined end to end
-xylem hollow/phloem few subcellular structures so stuff can flow through them
what are conditions caused by faulty cells
type 1 diabetes caused by pancreatic cells that normally produce insulin
paralysis-damaged nerve cells
drawbacks of embyronic stem cells
-limited supply
-ethical issues
-rejection
pros and cons of adult stem cells
pros
-can be taken from patient so wont cause rejection
-easy to get a hold off
cons
-can only differentiate into blood cells
what are risks of stem cells
virus transmission
tumour development
what are ethical objections
religious /moral grounds object to use as they have potential for life
some think curing people suffering should be prioritised
what factors affect rate of diffusion
-conc gradient
-temperature-particles move around faster and diffuse quicker
-surface area
-diffusion distance
what differs osmosis and diffusion
it is with water and it is through a semi permeable membrane
what is the water concentration
amount of water compared to solutes
proportion of water to solutes
active transport always happens
across a membrane
where is active transport used
in root hair cells which have lots of mitochondria and large sa to absorb mineral ions
isotonic,hypotonic,hypertonic
isotonic-same
hypertonic-more conc of solute
hypotonic-less conc of solute
Give two examples of exchange surfaces in humans and describe their function.
example 1 - Alveoli (or lungs)
Example 1 - Alveoli allow oxygen and carbon dioxide to diffuse in and out of the body/bloodstream
Example 2 - Villi (or small intestines)
Example 2 - Villi allow nutrients such as glucose, amino acids, mineral ions etc to be absorbed from the small intestines into the bloodstream
what are the common features specialised exchange surfaces in plants and animals
large surface area
thin-so short diffusion distance
permeable to substances they need to exchange
what does good blood supply do
helps maintain conc gradient in animals
what does good supply of external medium
air outside our body or food
State and explain three features of alveoli that make them good exchange surfaces.
Feature 1 - There are lots of alveoli, giving a large total surface area
Explanation 1 - Lots of molecules can diffuse across at the same time
Feature 2 - Surfaces are very thin (only 1 alveolar cell and 1 capillary cell thick)
Explanation 2 - Substances only have to diffuse a short distance
Feature 3 - Surfaces are permeable
Explanation 3 - Oxygen and carbon dioxide are able to diffuse across
Feature 4 - Good blood supply (good supply of ‘internal medium’)
Explanation 4 - Maintains a strong concentration gradient as blood is constantly replaced
Feature 5 - Good supply of air ( good supply of ‘external medium’)
Explanation 5 - Maintains a strong concentration gradient as the air in the alveoli is constantly replaced with new oxygen rich air from the atmosphere
