B1 Cell Structure And Transport

Question 1

Give 3 examples of eukaryotic cells

Answer 1

Animals, plants, fungi, protactists

Question 2

What is an example of a prokaryotic cell?

Answer 2

Bacteria

Question 3

What are the qualities of a eukaryotic cell?

Answer 3

• Contain membrane bound sub-cellular structures
• Membrane bound nucleus
• Length is 5-10 um
• Divide by mitosis
• Cellulose cell wall

Question 4

What are the qualities of a prokaryotic cell?

Answer 4

• Don’t contain membrane bound sub-cellular structures
• DNA free in cytoplasm
• Much smaller (1-5 um)
• Divide by binary fission
• Cell wall of peptidoglycan

Question 5

What are the properties of a light microscope?

Answer 5

A type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. It is light, small and less expensive but has a lower max magnification and resolution.

Question 6

What are the properties of an electron microscope?

Answer 6

An electron microscope is a type of microscope that achieves incredibly high resolution and magnification by illuminating the object under examination with a beam of electrons instead of a beam of light.

Question 7

How do you find the actual size of something using the image and magnification?

Answer 7

Image/ magnification

Question 8

A student views the image of a cell magnified 40 000 times. The image is 50 mm long. Calculate the
actual length of the sample in micrometres.

Answer 8

I/M = 50,000/40,000 = 1.25 micrometres

Question 9

What is a solute?

Answer 9

A solute is a solid which can disolve into a liquid

Question 10

What is a solvent?

Answer 10

A solvent is a liquid that a solute can disolve into

Question 11

What is the definition of diffusion?

Answer 11

Diffusion is the net movement of particles from an area of high concentration to an area of low concentration, down a concentration gradient until an equilibrium is reached. The gradient is steepest at the beginning as there is more crustal to be diffused.

Question 12

Why is diffusion important for cells?

Answer 12

Single-cell and multicellular organisms need to take in substances and transfer nutrients such as glucose and oxygen for respiration. They also need to get rid of waste products that are needed elsewhere in your body.

Question 13

What sprt pf substances move into and out of cells?

Answer 13

Substances that move into cells include glucose and oxygen for respiration. Substances that move out of cells include waste products, chemicals, needed elsewhere in the body, and dissolved substances and gasses which move across the cell membrane. These also include gasses such as oxygen and carbon dioxide and waste products such as urea for the breakdown of amino acids in your liver.

Question 14

What is osmosis?

Answer 14

Osmosis is the diffusion (net movement) of water particles from a more dilute solution to a more concentrated solution, across a partially permeable membrane.

Question 15

What is it called when the solution is equally concentrated as the inside of the cell?

Answer 15

The solutions are isotonic

Question 16

What is it called when the solution is more concentrated than the inside of the cell?

Answer 16

The solution is hypertonic

Question 17

What is it called when the solution is less concentrated than the inside of the cell?

Answer 17

The solution is hypotonic

Question 18

What is the difference of when osmosis occurs in an animal cell and in a plant cell?

Answer 18

As plant cells have outer structure, cellulose cell wall, they bulge when water enters through osmosis but do not burst. Whereas when water enters an animal cell, it bulges and bursts as it has no outer structure; cell wall.

Question 19

What is lysis?

Answer 19

Lysis is when animal cells placed in a dilute solution will take in water and therefore burst.

Question 20

What is crenation?

Answer 20

Crenation is when animal cells placed in a concentrated solution lose in water and therefore shrivel.

Question 21

What is plasmolysed?

Answer 21

When a plant cell loses too much water, it shrinks and the cell membrane eventually pulls away and detatches from the cell wall.

Question 22

What is flacid?

Answer 22

When the solution surrounding plant cells is more concentrated than the solution inside the cells, water moves out of the cells. This will cause the vacuole to shrivel. This causes low ‘turgor pressure’ and the cells
are said to be flaccid. As a result, the plant will wilt.

Question 23

What is the definition of turgid?

Answer 23

When the solution surrounding plant cells is more dilute than the solution inside the cells, water moves into
the cells. This causes the vacuole to swell. This causes high ‘turgor pressure’ and the cells are said
to be turgid. As a result, the plant will be rigid.

Question 24

What is active transport?

Answer 24

Active transport is the movement of particles against the concentration gradient through a partially- permeable membrane, requiring special transport protein and energy from respiration to do so. This is the opposite of diffusion.

Question 25

How is active transport used by plant cells?

Answer 25

For plants to take up mineral ions, ions are moved into root hair cells. They move from the lower concentration of ions from the soil into the higher concentration within the cell. This occurs through the process of active transport as the ions diffuse across the root from the soil.

Question 26

How is active transport used by animal cells?

Answer 26

In animal cells, glucose must be moved theough the surface of the gut wall into the blood. At times, the concentration of glucose in the intestine may be higher than that of in the cells. However, when the concentration is lower than the cells, active transport occurs for the movement of glucose from the intestine into the intestinal cells, requiring energy produced by respiration to do so.

Question 27

What must always be 1 within a SA:V ratio?

Answer 27

The volume

Question 28

The larger the size of the organism, the ________ the SA:V ratio

Answer 28

Smaller

Question 29

How is a nerve cell specialised for its job?

Answer 29

Long thin cells allow electrical signals to travel from
sensory organs to the brain and to muscles.
Main body of the cell the axon is insulated with
substance called myelin to prevent the electrical
signal leaking out of the cell.

Question 30

How is a sperm cell adapted for its job?

Answer 30

• a long tail whips from side to side to help move the sperm throught water or the famale reproductive system
• The middle section is full of microchondria, which transfers the energy needed fro the tail to work
• The acrosome stores digestive enzymes for breaking down the outer layers of the egg
• A large nucleus contains the genetic information to be passed on

Question 31

How is a muscle cell adapted for it’s job?

Answer 31

• They contain special proteins that slide over eachithee making fibres contract
• They contain many mitochondria to transfer the enegry needed dor chemical reactions that take place as cells contract and relax
• They can store glycogen, a chemical that can be broken down and used in cellular respiration by the mitochondria ot transfer the energy needed for the fubres to contract

Question 32

How is a ciliates epithelial cell adapted for its job?

Answer 32

• Has a thin llayer of tiny miving ‘hairs’ called cilia
• Push and move mucus from one place to another
• The cilia in the respitaory tract move mucis containing trapped microbes and dust

Question 33

How are red blood cells adapted for its job?

Answer 33

• Contains haemogkobin, a pigment that carries oxygen
• Does not contain a nucleus, which inreases the volume of haemoglobin in the cell
• Very felxible so it can move through narrow blood vessels
• Transports oxygen from the lings to the body tissues for aerobic respiration

Question 34

How are rpot hair cells adapted for their job?

Answer 34

• They greatly increase the surface area available for water to mive into the cell
• They have a large permanent vacuole that speeds up the mivement of water by osmosis from the soil across the root hair cell
• They have many mitochondria that transfer the energy beeded for the active transport of mineral ipns into the root hair cells

Question 35

How are xylem cells adapted for their job?

Answer 35

• The xylem cells are alive when they are first formed but a special chemical called lignin builds up in spirals in the cell walls. The cells die and form long hollow tubes that allow water and mineral ions ot move easily through them, from one end pf the plant to the other
• The spirals and rings of lignin in the xylem cells make them very strong and help the, withstand the pressure of water moving up the plant. They also help support the plant stem

Question 36

How are phloem cells adapted for their job?

Answer 36

• The cell walls between the cells break down to form special sieve plates. These allow sucrose to move freely up and down the tubes to where it is needed
• Phloem cells lose a lot of the internal structures but they are spported by companion cells that help keep them alive. The mitochondria pf the companion cells transfer the energy needed to move water up and down the plant in phloem

Question 37

What is it called when a cell loses water in an animal cell v plant cell?

Answer 37

Animal: Crenated
Plant: Flaccid/ plasmolysed

Question 38

What is it called when a cell gains water in an animal cell v plant cell

Answer 38

Animal: Lysed
Plant: Turgid

Question 39

What is turgor pressure?

Answer 39

Turgor pressure is the force within the cell that pushes the plasma membrane against the cell wall.

Question 40

Write a method for osmosis within potatoes in different concentrated solutions

Answer 40

Cut potatoes: Cut up into equal size 3cm length cylinders using a cork borer/ chipper, cutting off the skin as it less permeable.
Measure and record: Measure the mass of each potato piece.
Place in solutions: Put each piece of potato in a different beaker with a sugar
solution (one with distilled water, 10%, 20%, 30%, 40%, 50% sugar).
Wait: Leave the potato pieces in the solutions for 20–30 minutes.
Take out and dry: Remove the potato pieces, dry them with a paper towel, and
measure their mass.
Compare: Compare the mass with the original and calculate the percentage increase or decrease

Question 41

What will be the effects on the potato within the low and high concentrations?

Answer 41

Low concentration (dilute): When the potato chip is placed in a dilute solution, the water moves into the cell through osmosis, causing it to gain mass as the outer solution is hypotonic; the water moves from the more dilute solution to the more concentrated cell and the cell becomes turgid.

High concentration: When the potato chip is placed into a more concentrated solution, water moves out of the cell through osmosis, causing it to lose mass as the puter solution is hypertonic; water moves from the more dilute cell to the more concentrated outer solution and the cell becomes flacid.

Question 42

Write a method on preparing a microscope slide

Answer 42

1. Use a dropping pipette to put a drop of water onto a glass slide
2. Seperate one of the thin layers of the onion.
3. Use tweezers to peel off some epidermal tissue from the bottom of one of the layers
4. Place this thin layer on to the dr of water on the slide
5. Make sure that the layer of onion cells is flat on the side
6. Put 2-3 drops of iodine solution on the onon tissue
7. Use a piece of blotting paper to soak up any excess liquid on the slide
8. Carefully, lower a coverslip onto the slide. Do this by placing one edge of the coverslip on the slide at a 90° angle and use the mounted needle to lower the other edge onto the slide
9. Put the prepared slide on the microscope stage