Chapter 2

Question 1

Cell/ plasma membrane

Answer 1

Encases both plant and animal cells. Controls the movements of substances in and out of the cell. Phospholipid bilayer, semi permeable.

Question 2

Nucleus

Answer 2

Organelle containing DNA eukaryotic cells, surrounded by a nuclear membrane, has gaps/pores to allow DNA message to get out.

Question 3

Mitochondria

Answer 3

(Energy supplying organelle)

• site of cellular respiration where sugars are broke down to release stored chemical energy (ATP)
• has its own dna, similar to bacterial DNA

Question 4

Ribosome

Answer 4

Protein factories

• site of protein synthesis where amino acids are linked together to form polypeptide chains.
• “free” ribosomes float in the cytosine and make protein for use within the cell.

Question 5

Rough Endoplasmic reticulum

Answer 5

• rough Er: is covered in ribosomes and the proteins made at ribosomes move through the membrane channels of the ER (designed for use outside of the cell)

Question 6

Smooth Endoplasmic Reticulum

Answer 6

Lacks ribosomes and functions in lipid manufacturing and metabolism, the production of steroid hormones and detoxification.

Question 7

Golgi apparatus

Answer 7

Transport of substances out of cells

• proteins made at ribosomes, destined for secretion, move from the ER to the Golgi to be concentrated and packaged into secretory vesicles
• vesicles may be stored in cytosol or move to the plasma membrane and discharged from the cell by exocytosis

Question 8

Lysosomes

Answer 8

• Membrane sacs filled with digestive enzymes

- “self- destruction”- involved in controlled cell death by destroying unwanted cell parts or damaged cells

Question 9

Chloroplasts

Answer 9

Site of photosynthesis

• trap sunlight energy and convert into chemical energy stored in sugars
• inner membranes for stacks are called grana
• fluid filled spaces between the grana called stroma contain enzymes for photosynthesis
• chloroplasts contain DNA, ribosomes and reproduce independent of their cell “host”

Question 10

Cell wall

Answer 10

Present in plants, fungi and prokaryotic cells

• acts as pressure vessels, preventing over- expansion when water enters the cells.
• tough and flexible it provides cells with structural support and protection
• made of carbohydrates or glycoproteins

Question 11

Vacuole

Answer 11

• storage bubbles found in both animal and plant cells (much larger in plant cells)
• can store food, nutrients, fluids and wastes (so the rest of the cell is protected from contamination)
• vacuoles contribute to the turgor pressure in plant cells.

Question 12

Cytosol

Answer 12

Insta- cellular fluid present inside the cell

Question 13

Cytoplasm

Answer 13

• a thick gel- like solution that fills each cell and is enclosed by the cell membrane, mainly composed of water, salts and protein
• in eukaryotic cells the cytoplasm includes all of the material inside the cell and outside the nucleus

Question 14

Simple diffusion

Answer 14

• movement of a substance along a concentration gradient ( from a region of high concentration to low concentration)
• passive process (no energy required)

Question 15

Osmosis

Answer 15

Movement of water molecules by diffusion across the cell membrane
- high water concentration to low water concentration

Question 16

Facilitated diffusion

Answer 16

Large particles, such as glucose and charged ions may need help to diffuse into cells. Substances still follow the concentration gradient.

Question 17

Active transport

Answer 17

• energy has to be expended to move things against the concentration gradient
• when energy is provided carrier protein take up particles on one side of the plasma membrane and releases them on the other side.
• low concentration to high concentration

Question 18

Organelles

Answer 18

Membrane- bound structures that are found inside cells and carry out different functions.

Question 19

Prokaryotic cells;

Answer 19

• little internal structure
• lack an enclosed nucleus for their DNA
• don’t contain membrane- bound organelles
• contain ribosomes
• eg, bacteria

Question 20

Eukaryotic cells;

Answer 20

• more complex structure

- contain many different membrane bound structures called organelles

Question 21

Endosymbiosis theory;

Answer 21

The idea that mitochondria and chloroplasts were once primitive bacteria cells which were ingested by a larger host cell.

Question 22

What is a hypotonic solution?

Answer 22

• more solutes inside the egg, less outside the egg.

- more watery, less solutes

Question 23

What is an isotonic solution?

Answer 23

• same amount of solutes inside and outside the cell

Question 24

What is a hypertonic solution?

Answer 24

• more solutes outside the egg and less inside the egg

- more solutes, less water

Question 25

Methods of bulk transport

Answer 25

• endocytosis; a way of taking larger particles into the cell (that cannot pass through the cell membrane)
• exocytosis; the release of a material out of the cell (digestive enzymes or hormones may be released by the cell)

Question 26

What’s phagocytosis?

Answer 26

Where solid particles are taken into a cell via bulk transport

Question 27

What is Pinocytosis?

Answer 27

Where a liquid is taken into a cell via bulk transport.

Question 28

What are the steps involved in programmed cell death?

Answer 28

Apoptosis.
Death signalling molecules attach to the cell membrane. Caspase enzymes break down DNA and nuclear proteins. Cell breaks up into membrane bound fragments that are ingested by phagocytes. Some components are recycled.