Biology-Transport of substances

Question 1

Name the 4 main sustances required to move in and out of cells

Answer 1

• Oxygen
• Carbon Dioxide
• Glucose
• Water

Question 2

What name is given to the sturcture of a cell mermbrane

Answer 2

Partillary permanable mermbrane

Question 3

Describe the process of diffusion.

Answer 3

The movement of a substance from an area of high concentration to an area of lower concentration (a passive process=no ATP/energy required).

Question 4

Describe how temperature and concentration gradient affect the rate of diffusion, and explain why.

Answer 4

The greater the difference in concentration, the quicker the rate of diffusion. The higher the temperature, the more kinetic energy the particles will have, so they will move and mix more quickly.,increasing diffusion rate.

Question 5

State some examples of diffusion in living organisms

Answer 5

• Gas exchange in lungs and leaves
• Movement of oxygen into cells,
• Waste removal via kidney
• Nutrient uptake through small intestine

Question 6

Use the special term OSMOSIS to describe the diffusion of water through a partially permeable membrane

Answer 6

Osmosis is a special case of diffusion1that describes the diffusion of water molecules through a partially permeable membrane. Water molecules move from a region where they are in higher concentration to a region where they are in lower concentration. A dilute solution contains a high concentration of water molecules, while a concentrated solution contains a low concentration of water molecules.

Question 7

Describe a example solution’s solute and solvent

Answer 7

A solution of salt and water, for example, has water as the solvent and salt as the solute.

Question 8

What happens to the concerntration of a solvent, when more solute is added

Answer 8

High concentration of solute = a low concentration of free water

Question 9

What is the difference between
the terms isotonic, hypotonic and hypertonic

Answer 9

HYPERtonic = more solute (think: sugar makes you hyper!)
HYPOtonic = less solute (think: hypo is low)
ISOtonic = the same amount as solute

Question 10

Describe the effects of osmosis on animal cells

Answer 10

• Animal cells take in and lose water by osmosis.
• They do not have a cell wall, so will change size and shape when osimosis is performed
• This can make cells become cytolysis(burst due to too much water) and crenated(compressed due to too little)
• Therefore in animals, the concentration of body fluids - blood plasma and tissue fluid must be kept within strict limits

Question 11

Describe the effects of osmosis on plant cells

Answer 11

• Plants diffuses water from a higher water concentration outside the cell to a lower water concentration inside the cell.
• The presence of the plant cell wall prevents plant cells from bursting/compressing to cytoliysis/crenation
• Rather osimosis induces cell turgor(equal osimetic pressure), keeping the cell sturcture ,and stenghtening the cell
• However lower osmotic pressure(Flaccid) Doesn’t protect as effectivitely from injuries
• Too low of osmotic pressure causes the cell to become plasmolysed, and the mermbrane to pull away from the cell wall

Question 12

Describe a practical on how to investigate the effect of a range of concentrations of salt/or sugar solutions on the mass of plant tissues

Answer 12

To investigate the effect of a range of concentrations of salt or sugar solutions on the mass of plant tissue, you can prepare samples of potato and place them in different concentrations of sugar or sodium chloride (salt) solution. You will then make measurements of mass and length of your samples before and after soaking them in solutions.

This experiment involves using an apparatus to prepare dilutions of sugar or salt and assess the effect of different concentrations.

Question 13

State the difference between a passive and an active process.

Answer 13

A passive process occurs without utilising any energy.An active process requires the presence and utilisation of energy to take place.

Question 14

Describe how molecules can move by active transport

Answer 14

Active transport uses ATP/energy to move molecules across a cell membrane ,against the concentration gradient, using specific helper proteins in the membrane

Question 15

Where does the ATPs/energy for active transport comes from.

Answer 15

Adenosine triphosphate , made through respiration in mitochondria

Question 16

Describe some examples of active transport in organisms

Answer 16

• Ion uptake by root hair cells
• Glucose/amino acids absorption in the small intestine.
• Phagocytosis(digesting) of bacteria by Macrophages
• Movement of Ca2+ ions out of cardiac muscle cells
• Secretion of proteins like enzymes, peptide hormones, and antibodies from different cells

Question 17

Define

Surface area to volume ratio

Answer 17

The surface-area-to-volume ratio or SA:V is the amount of surface area of an organism divided by its volume.

Question 18

Describe the SA:Vol of smaller and larger organism

Answer 18

small organisms have a big SA:vol, whilst big organisms have a small SA:vol

Question 19

How does SA:Vol link to diffusion

Answer 19

As the ratio gets smaller, it takes longer for items to diffuse. 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.

Question 20

Describe examples of exchange surfaces/adapations for exchange

Answer 20

• The gills of fish
• The network of blood capillaries that surrounds each of the alveoli in the lungs
• The network of blood capillaries in each of the villi in the small intestine
• The nephrons in the kidney
• The root hairs of plants
• The hyphae of fungi