B2.1 Flashcards
diffusion
the net movement of particles from an area of high concentration to an area of low concentration
active transport
movement of molecules against the concentration gradient from a low concentration to a high concentration
what kind of process is diffusion?
a passive process, no energy is needed
concentration gradient
a difference in concentration between 2 areas
what kind of process is active transport?
it is a process that requires energy
water potential
a measure of the ability of water to move
osmosis
the net movement of water from a high water potential to a low water potential through a partially permeable membrane
factors which affect the rate of diffusion
-concentration
-temperature
-distance across
explain why tipping salt onto slugs kills them
-salt is a solute
-adding salt to the outside of the snail decreases the water potential
-this creates a concentration gradient
-so water moves via osmosis out of the snail
crenation
cell crumples up as it has no water
turgid
cell becomes swollen with water
lysis
cell bursts
flaccid
plant cell lacking water
plasmalysed
plant cell shrinks due to water moving out of cell
what are the parts of the cell cycle?
-interphase
-mitosis
-cytokinesis
what percentage does interphase make up of the cell cycle?
90%
what is interphase?
-growth
-replicates DNA
what percentage does mitosis make up of the cell cycle?
10%
what is mitosis?
type of cell division where a single parent cell divides into two identical daughter cells
what is the purpose of mitosis?
-growth
-tissue repair
-cell replacement
-asexual reproduction
what are the different phases of mitosis?
-prophase
-metaphase
-anaphase
-telophase
prophase
(PREPARE) the nucleus disappears and the chromosomes coil up to prepare for mitosis, spindle fibers start to form
metaphase
(MIDDLE) chromosomes line up in the middle of the cell
anaphase
(AWAY) chromatids are separated and pulled to opposite ends of the cell
telophase
(TWO) the nuclei reform around each set of chromosomes, the chromosomes uncoil and the cell prepares for cytokinesis
meristems
plant stem cells found in areas of new growth
potency
a measure of how many types of specialised cells a stem cell can make
pluripotent
can make all types of specialised cells in the body –> embryonic stem cells are pluripotent
multipotent
can make multiple types of specialised cells but not all types –> adult stem cells are multipotent
stem cells
undifferentiated cells that can replicate themselves or produce specialised cells through differentiation
slef renewing cells
maintains the number of stem cells
differentiating stem cells
makes 4 specialised cells to replace dead or damaged cells throughout your life
potential uses of stem cells
-spinal cord injury
-diabetes
-deafness
-blindness
how do you calculate actual size?
image size / magnification
differentiation
the process by which cells become specialized to perform specific functions in an organism
function of red blood cells
to deliver oxygen tissues
adaptations of red blood cells
-haemoglobin to bind to oxygen
-no nucleus to have more space for haemoglobin
-flexible to squeeze through capillaries
-biconcave to increase surface area to volume ratio
function of white blood cells
fights off infections
adaptations of white blood cells
-has a lobed nucleus to make it more flexible
-flexible to squeeze through blood vessels
function of sperm cells
deliver genetic information to an egg cell
adaptations of sperm cells
-flagellum to swim to the egg
-has lots of mitochondria to produce energy
-enzymes to break down the eggs cell membrane
function of palisade cells
plant cells that carry out photosynthesis
adaptations of palisade cells
-has chloroplasts with chlorophyll to carry out photosynthesis
-large vacuole to store water, minerals and sugars
function of root hair cells
absorb water for plants
adaptations of root hair cells
-elongated shape to reach more water
-large vacuole to store water
where can meristems be found?
-roots
-shoot apical
-stem
why can differentiated cells not divide in the plant?
they have no cell wall
where can stem cells be found?
-embryo
-foetus
why are stem cells so useful?
they can repair damaged and diseased organs
what type of cells do bone marrow stem cells differentiate into?
blood cells
where can adult stem cells be found?
-eye
-bone marrow
why is it useful to produce organs using the patients own stem cells?
so it doesn’t cause an infection
