Cells and movement across membranes Flashcards
factors affecting active transport
- respiration provides the energy required in the form of ATP
- glucose concentration
- oxygen
- temp
- toxic substances
how does temperature affect active transport
the higher the temp the higher amount of kinetic energy in the molecules
glucose concentration affecting active transport
respiration needs glucose
oxygen affecting active transport
aerobic respiration needs oxygen
temperature affecting active transport
affects the enzymes controlling respiration
toxic substances affecting active transport
stops respiration
cheek cell experiment - animal cell
- drop of methylene blue on glass slide
- rub inside of cheek with bud
- wipe bud in the methylene blue on slide
-place bud in disinfectant
-use mounted needle to lower cover slip - use a light microscope
how do you calculate maginification
eyepiece X objective lens
cell membrane
controls substances entering and leaving the cell
what process releases the energy required for active transport
respiration
what is the green pigment in chloroplast
chlrophyll
where does osmosis occurs
across a semi permeable membrane which has tiny holes, these are small enough for water molecules to pass through but larger molecules cant
what is a group of cells that do the same function
tissue
what is a group of organs working together to carry out a specific function
organ system
what are two chemicals needed for active transport
- ATP
- Oxygen
what is the name of the non-living semi permeable membrane that is often used in experiments to demonstrate osmosis
visking tubing
2 things that can speed up the rate of diffusion
- temperature
- pressure
- concentration
methylene blue
stains acidic parts of the cell blue
makes the nucleus more obvious
mostly used o prepare slides of animal cells and bacteria
iodine solution
makes the nucleus more obvious and stains any starch present. mostly used to stain plant cells
biological staining
stains are used to help us see cells in greater detail
structure of the cell membrane
there are many pores in the surface of the cell membrane, molecules that are small enough can pass directly through these pores, large molecules are prevented
organ
several tissues performing specific functions
how can concentration affect the rate of diffusion
the greater the difference in concentration between the two areas the faster the rate diffusion happens
electron microscopes
it uses a beam of electrons instead of light
its possible to get magnification up to x 50000000
you can only study dead cells
whats no net movement
when there is no change in the cell during osmosis/ so there is equal amounts of water concentration each side
why does a root hair cell have a large surface area
increased absorbtion
mitochondria
site of aerobic respiration
how can pressure affect the rate of diffusion
if there is high pressure, the molecules will quickly move from the area of high pressure to low pressure
chloroplast
absorb light for photosynthesis
nucleus
contains chromosomes which carry genetic info and controls the activities of the cell
cytoplasm
where most chemical reactions take place
onion cell experiment ( plant cell)
-using foreceps , peel thin layer of epidermis from inside of onion
-lay epidermis on glass slide
-add iodine solution to the onion on slide
- use mounted need to lower coverslip
-use light microscope
animal cells concentrated solution
water moves out of the cell through the semi permeable membrane, the cell shrivels due to no cell wall
what happens when the membrane is boiled
it becomes denatured, this means that the pores become larger and both water and solute are able to move both ways
sperm cell
these carry half the genetic info. they have tails to swim towards the egg cell
what is the risk of methylene blue and what control measure do you takw
-its harmful and irritant
-the risk is methylene blue can irritate eyes and lungs
- control measure= lowest concentration and eye protection
what is the risk of cheek cells
- they are a biohazard
-small risk of virus transmission - control measure= handle samples from own body, hygienically dispose cotton buds in disinfectant
how can temp affect the rate of diffusion
as the temp increases, the rate of diffusion increases too
muscle cell
these cells can change their length to help us move
when do we see the process of mixing and moving
we see this in diffusion
molecules of liquids and gases collide against each other all the time
dilute solution
has a low solute concentration and therefore a high water concentration
palisade cell
these cells contain chloroplasts to help the plant make food by photosynthesis
red blood cell
these cells are adapted to carry oxygen to cells and carbon dioxide away from them
ciliated epithelial cell
these cells are found in tubes leading to the lungs and in the oviduct. the hairs move dirt out of the lungs and help to move eggs along the oviduct
what is the risk of coverslip/ mounted needles
- they are sharp
-can cut skin
-handle them carefully
what is the simplest form of living organisms that are made of one cell called
unicellular organisms
what are organisms called that consist of many cells
multi cellular
specialised cells
cells differentiate to cells with a specific function
diffusion
molecules diffuse from an area of high concentration to an area of low concentration
how does the cell membrane control movement in and out of the cell
every substance that enters or leaves a cell must cross the cell membrane. molecules will pass easily through the cell membrane whilst others are unable to pass through
vacuole
space filled with cell sap ( a dilute solution of sugars and mineral salts )
cell wall
contains cellulose, it supports the plants structure
nerve cell
these cells can be very long to carry messages around the body
active transport
salts or ions are pumped from an area of low concentration to an area of high concentration AGAINST THE GRADIENT
this requires energy released by the cell
osmosis
is the diffusion of water molecules from an area of high concentration to an area of low concentration across a selectively permeable membrane
animal cells dilute solution
water moves in to the cell through the semi permeable membrane. the cell swells and may burst because there is no cell wall
plant cells concentrated solution
water moves out of the cell through the semi permeable membrane. the cell becomes flaccid, doesnt shrivel because of cell wall
concentrated solution
has a high solute concentration and therefore a low water concentration
root hair cell
the root hair gives these cells a bigger surface area to take in water from the soil
plant cells dilute solution
water moves into the cell through the semi permeable membrane, the cell becomes turgid, the cell wall prevents it from bursting
