Biology yr 9 Spring Term Flashcards
hetrozygous
an organism where the alleles for a given trait are different
Name the three methods of transport.
diffusion, osmosis, active transport
active transport
the movement of a substance against a concentration gradient (from low to high) using energy from respiration.
flaccid
when the plant is placed into a saturated solution and looses water
hypotonic solution
a solution which is less concentrated than the inside of the cell
adult animal stem cells
found only in specific areas of the body and can only develop into a limited number of cell types
found in adult animals
concentration gradient
the difference in concentration of a substance between two areas
a region of high concentration leading to a region of low concentration
problems with adult stem cells
- can only differentiate into smaller number of types of cells compared to embryonic stem cells
- donation can be painful
Why do we need active transport?
- absorbing of mineral ions from soil
- movement of glucose from gut to kidney
- removal of salt from the body of marine animals
- absorption of ions from very dilute solutions
Why do multicellular organisms have a small surface area to volume ratio?
to be able to get all of the substances that cells need to the correct place.
homozygous
an organism where both alleles for a given trait are the same
passive
does not require energy from respiration
homologous
describes a matching pair of chromosomes
How to gain marks on osmosis questions
- State where is the solute concentration the highest
- State that osmosis is the movement of water
- State that water moves from an area of low solute concentration (high water concentration) to an area of higher solute concentration (low water concentration)
- State that this is across a partially permeable membrane
- State the direction in which the water will move and what you will see in the experiment
benefits of using embyonic stem cells
- can treat a wide variety of diseases as cells can differentiate into a much larger number of types of cells compared to adult stem cells
- many are available for use as they are taken from discarded IVF embryos and they would potentially go to waste otherwise
- no pain for donor
plasmolysed
when a plant cell is placed into a concentrated solution is becomes
factors that affect diffusion
- concentration gradient
- temperature
- ## (membrane) surface area
net
overall movement
some particles might move in different directions but overall movement
meristems
unspecialised cells in plants that are capable of differentiating to become any type of specialised cell
found at the tips of their roots and shoots.
Which part of the cell membrane shrivels when a plant cell is placed in a concentrated solution ?
cell membrane
benefits/risks of using adult animal stem cells
- no ethical issue in collection as permission given
- quick recovery
- relatively safe (doesn not kill donor/low risk)
- well tested
hypertonic solution
a solution which is more concentrated than the inside of the cell
lysis
the bursting of an animal cell an animal cell in a less concentrated solution
What is a membrane that only allows certain materials to pass through them called?
selectively permeable
turgid
when the plant is placed into a dilute solution and takes up water
osmosis
the movement of water from a dilute to a more concentrated solution through a partially permeable membrane that allows the passage of water molecules
diffusion
the movement of particles from a high to a lower concentration
isotonic solution
a solution which is equal in concentration to the inside of the cell
problems with embryonic stem cells
- death to embryo
- relatively untested
- long term effects not known
- consent cannot be obtained from the embryo
equilibrium
when the concentrations are equal throughout an area or inside and outside a cell
crenation
what happens to an animal cell if we place an animal cell in a more concentrated solution
embryonic stem cells
stem cells are only found in embryos that can differentiate into any specialised cell type that make a human
allows an embryo to develop a variety of tissues and organs as they develop
