B1 Cell Strucutre And Transport Flashcards
What is the first step in using a light microscope?
Always start on low power with a clean slide. The stage of the microscopes should be down as low as possible.
What is the second step in using a light microscope?
Centre the slide so the specimen is underneath the objective lens.
What is the third step in using a light microscope?
Use the Coarse adjustment knob to obtain a general focus. You will be slowly raising the stage until a focus is achieved.
What is the fourth step in using a light microscope?
Use the fine adjustment knob to obtain a clear focus.
What is the fifth step in using a light microscope?
Centre the specimen in the low power field of view before you move to medium power.
What is the 6th step in using a light microscope?
Without any further adjustments, switch the objective lens to medium then focus using the fine adjustment. If you cannot see the specimen at this point, go back to low power and re-centre and refocus it.
What is the seventh step in using a light microscope?
Once you have it focused and centred on medium power, you can progress to high power.
describe the difference between magnification and resolution.
Magnification is the ability to make small objects seem larger, such as making a microscopic organism visible. Resolution is the ability to distinguish two objects from each other.
state why microscopes are useful in the study of cell biology.
The microscope is important because biology mainly deals with the study of cells (and their contents), genes, and all organisms. Some organisms are so small that they can only be seen by using magnifications of ×2000−×25000 , which can only be achieved by a microscope.
Equation for Magnification
Magnification= Actual size divided by image size
Equation for Actual size
Actual size = image divided by magnification
Equation for size of image
Magnification x actual size
How do you convert km to m ?
x1000
How do you convert m to mm?
x1000
How do you convert mm to um?
x1000
How do you convert um to nm ?
x1000
How do you convert nm to um ?
÷1000
How do you convert um to mm
÷1000
How do you convert mm to m
÷1000
How do you convert m to km
÷1000
What is the function of the nucleus?
To contain genetic material that controlling the activities the cell
What is the function of the cytoplasm?
The site where most chemical reactions happen
What is the function of the cell membrane?
To hold the cell together and controls what goes in and out
What is the function of the mitochondria?
to help with aerobic respiration
What is the function of the ribosomes?
To make proteins via protein synthasis
What type of cell are bacteria?
prokaryotes
Does a bacterial cell have a nucleus?
No
What are chloroplasts?
where photosynthesis occurs. they make the energy for the plant
What are sperm cells specialised for?
reproduction
streamlined head and long tail
What are nerve cells specialised for?
rapid signalling
long axons and have branched connections
What are root hair cells specialised for?
absorbing water and minerals- big surface area
What do chromosomes do?
contain genetic information
What is a eukaryotic cell?
They contain membrane bound organelles such as a nucleus and mitochondria.
What is a plasmid?
a circular strand of DNA that floats freely in the cytoplasm
what does xylem transport?
water and minerals
what does phloem transport?
Sugars
in what direction can the phloem transport
roots to leaves
leaves to roots
what process do plants need to move water for?
photosynthesis
What is a stem cell
A single cell that can replicate it self or differentiate into many cell types
What is the function of a red blood cell
The primary function of red blood cells is to carry oxygen from the lungs to the body tissues and carbon dioxide as a waste product, away from the tissues and back to the lungs.
What is a white blood cell
White blood cells are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders.
What is a nerve cell
a neuron
What is a muscle cell
is the type of cell found in muscle tissue.
What is a Palisade cell
Palisade cells are plant cells located on the leaves, right below the epidermis and cuticle.
What is the function of Palisade cell
The palisade cell consists of chloroplasts with chlorophyll that absorb the light energy.
explain why animals have specialised cells.
The cells in many multicellular animals and plants are specialised , so that they can share out the processes of life. They work together like a team to support the different processes in an organism.
a basic explanation of how animal cells are adapted.
Each is adapted to a perform specific functions, such as carrying oxygen, contracting muscles, secreting mucus, or protecting organs.
What is Diffusion?
Diffusion is the movement of particles from an area of high concentration to an area of low concentration, down a concentration gradient. This continues until equilibrium is reached.
What sort of substances are in and out of cells by diffusion?
Oxygen , carbon dioxide , glucose , waste products e.g urea
What is Concentration?
Concentration is a measurement of how much solute is dissolved in a given
volume of solvent.
What is water potential ?
Water potential relates to the ability of water to move freely
What prevents water from moving freely?
Solutes prevent water from moving freely
list the factors that affect the rate of
diffusion.
the mass of the solute,
the temperature of the environment, the solvent density,
the distance traveled.
explain why surface area affects the rate of diffusion.
When the cell increases in size, the volume increases faster than the surface area, because volume is cubed where surface area is squared. When there is more volume and less surface area, diffusion takes longer and is less effective. T his is why cells divide.
what is osmosis?
Osmosis is the net diffusion of water from a dilute solution across a partially permeable membrane.
what is an isotonic solution?
the concentration of solution outside the cell is the same as the concentration of inside the cell
what is a hypertonic solution?
the concentration in the solution is higher than the concentration inside the cell
what is a hypotonic solution?
the concentration of the solution is lower than the inside of the cell the solution
What is Active Transport?
Particles move from an area of low concentration to an area of high concentration , across a partially permanable membrane
This requires energy (and special transport protein)
what happens when water leaves a plant cell? why?
If more water is lost by osmosis , the vacuole and cytoplasm shrink, and eventually the cell membrane pulls away from the cell. This is plasmolysis.
what happens when water enters a plant cell? why?
Water moves into plant cells by osmosis causing the vacuole to swell which presses against the cytoplasm against the planet cell wall. The pressure builds up until no more water can physically enter the cell. The pressure is known as turgor. Turgor pressure makes the cells hard and rigid.
what is lysis in animal cells? why does it happen?
Animal Cells placed in a dilute solution will take in water and therefore burst. Thsi is called lysis.
what is crenation in animal cells? why does it happen?
Animal Cells placed in a concentrated solution will lose water and therefore shrivel. This is called crenation.
what is a dilute solution?
A dilute solution of sugar contains a high concentration of water ( the solvent). It has a low concentration of sugar ( the solute ).
what is a concentrated solution?
A concentrated sugar solution contains a relatively low concentration of water and a high concentration of sugar.
state the differences between
osmosis and diffusion.
Osmosis is the movement of solvent particles across a semipermeable membrane from a dilute solution into a concentrated solution. Diffusion is the movement of particles from an area of higher concentration to lower concentration.
How do plants use active transport?
Plants use active transport to move mineral ions from the soil into the roots against a concentration gradient
why active transport is
important for living organisms.
Active transport is important because it allows the cell to move substances against the concentration gradient.
where active transport takes
place.
The process of active transport takes place in humans during digestion of food in the ileum (small intestine).
state the function of exchange
surfaces in animals.
In many animals, this is the bloodstream. They also need specialised exchange surfaces where substances can enter and leave the transport system by diffusion. An example is the lungs in mammals. Exchange surfaces are adapted to increase their surface area to maximise the rate of diffusion.
State the function of exchange surfaces in plants?
In plants, the main exchange surfaces are the leaves and roots. Leaves have evolved to allow the efficient gaseous exchange of oxygen and carbon dioxide with the air during photosynthesis. Molecules of carbon dioxide enter the leaves through tiny pores called stomata A plant also needs water and mineral ions.
describe how the effectiveness of
exchange surfaces is increased.
The process of breathing, or ventilation , brings air to, and removes air from the exchange surface – the alveoli. The moving blood and ventilated surfaces mean that a steep concentration gradient can be maintained. This increases effective exchange.
How are alveoli adapted for exchange?
The alveoli have an enormous surface area and a very rich blood supply for gas exchange
How are stomata adapted for exchange?
Stomata help to provide a big surface area and maintain a steep concentration gradient for the diffusion of substances such as water, mineral ions and carbon dioxide
what is the relationship between SA:V
As living organisms get bigger and more complex their surface to volume ratio gets smaller.
What happens if the living organism gets bigger?
This makes it increasingy difficult to exchange materials quickly enough with the outside world
Examples of difficult exchange for living organisms with a small SA: V ratio
- Gases and food molecules can no longer reach every cell inside the organism by simple diffusion
- Metabolic waste can not be removed fast enough to avoid posining the cells.
