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Biology
B1 - Cell Biology
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Cards (40)
Diffusion
Particles/ molecules move from a
high concentration, to a low concentration
until an
equilibrium
is reached.
No
energy
required.
Osmosis
Movement of
water
particles from a
high
concentration
to a low
concentration
across a partially permeable membrane.
Factors
speeding
up
diffusion & osmosis
-
Higher
temperature
(particles gain
kinetic
energy)
-
Thinner
membranes
(
shorter
diffusion distance)
-
Higher
concentration
gradient
(takes longer for an
equilibrium
to be reached)
Water potential
Water concentration
Active transport
Particles move from a
low
concentration to a
high
concentration and requires
energy.
Diffusion (Examples)
- In the lungs (
Carbon Dioxide
,
oxygen
,
glucose
)
-
Carbon
dioxide
into plants via
stomata
Osmosis (Examples)
- Distilled
water
entering a
cell
-
Small
intestine
Active transport (Examples)
-
Root hair cells
(mineral ions from a
low
concentration in soil to a high concentration in root hair cell)
-
Small intestine
(glucose and amino acids from low concentration in small intestine to a high concentration in the
blood
using
energy
)
Light microscope
-
Low
magnification
-
Low
resolution
-
Living
sample
- Image in
colour
(from dye),
2D
- Image can be
blurry
-
Cheaper
- Used in
schools
Electron microsope
-
High
magnification
-
High
resolution
-
Dead
sample
- Image in
black
&
white
- Pass
electrons
through sample
-
Expensive
- Uses a
vacuum
Microscope parts
-
Eye piece
-
Arm
- Objective
lenses
-
Stage
-
Focus
-
Light
-
Base
Magnification
How much
bigger
an object appears to be than it really is when viewed through a
microscope.
(
Image
/
actual
)
Resolution
The
smallest
distance that can be seen between two points. (The smaller the distance, the
higher
the
resolving
power)
Metres order
Kilometres
,
metres
,
millimetres
,
micrometres
,
nanometres
Nucleus
Controls the cell's
activities
and contains
DNA
Mitochondria
Site of
respiration
(Release
energy
through respiration)
Cytoplasm
Site of
chemical
reactions
Cell membrane (inside)
Allows
chemicals
in and out of the cell
Cell wall
Strength
and
support
for the
cell
Ribosomes
Make
proteins
Vacuole
Stores
cell sap
(cell food) and keeps cell
turgid
(full)
Chloroplasts
Site of
photosynthesis
, contain
chlorophyll
Eukaryotic cells
- Have a
nucleus
-
Bigger
-
Mitochondria
Plants, animals, yeast
Prokaryotic cells
- No
nucleus
-
Smaller
- No
mitochondria
Bacteria
Sperm cell
Long
tail
,
pointy
head
- Help
swim
and
dig
into the egg
Muscle cell
Overlapping
edges - Allows muscles to
contract
, move
Nerve cell
Many
branches
- Carry more
nerve
impulses at a time
Root hair cell
Elongated shape,
tail
- Increase surface area to absorb more
water
Phloem
Little
cytoplasm
, no
nucleus
- More room for
sugars
Xylem
Pits,
lignin
-
Water
can move between adjacent cells,
stronger walls
Stem cell
A cell that hasn't undergone
differentiation
(all cells start off like this)
Mitosis
Cells divide to allow for
growth
, replace
damaged
cells (repair)
Production of new cells -
Duplication
DNA replicated
so form
two
copies of the
chromosomes.
Increase number of mitochondria, ribosomes, etc.
Production of new cells -
Mitosis
One set of
chromosomes
is pulled to each side of the
nucleus
and then the nucleus splits into
two.
Production of new cells -
Cleaving
Cytoplasm and cell membranes split and form two
genetically identical
cells.
Meristem tissue
Plant stem cell
Therapeutic
Relating to the
treatment
of a disease
Therapeutic cloning
1 - Need
two
cells; one from the
patient
and a
donated
egg cell.
2 - Remove
nucleus
from egg, skin cell and replace with patient's
nucleus.
3 -
Electric shock
is uses to stimulate cell
division
to develop into an
embryo
Used to treat cancer,
diabetes
, heart disease, infertility, regrow tissues, replace faulty organs
Animal stem cell -
Embryonic
Undifferentiated
( Allow them to develop into a foetus -
fertilised
egg cell)
Animal stem cell -
Adult
Differentiated
(specialised), used to
repair
damaged tissues and
replace
dying cells, found in blood, skin, brain, heart, liver etc.