1.1. Introduction to Cells

Question 1

What are the 3 main principles of cell theory?

Answer 1

1. All living things are composed of cells
2. The cell is the smallest unit of life
3. Cells only arise from pre-existing cells

Question 2

What are 3 examples of cells/tissues that do not conform the cell theory?

Answer 2

Striated muscle fibres, Aseptate fundal Hyphae, Giant Algae

Question 3

Striated muscle fibers challenges the idea that…

Answer 3

Cells always function as autonomous units because they have multiple nuclei despite being a single membrane

Question 4

How does Aseptate fungal Hyphae challenge cell theory?

Answer 4

It has a continuous cytoplasm, so challenges the idea that living structures are composed of discrete cells

Question 5

How does Giant Algar challenge cell theory?

Answer 5

It may be too large, so challenges the idea that larger organisms are always made of many microscopic cells

Question 6

What 7 characteristics are all living organisms capable of carrying out?

Answer 6

1. Metabolism
2. Reproduction
3. Response
4. Homeostasis
5. Excretion
6. Nutrition
7. Growth

Question 7

Define metabolism

Answer 7

Living things undertake essential chemical reactions that take place within an organism

Question 8

Define reproduction

Answer 8

Living things produce offspring, either sexually or asexually

Question 9

Define response

Answer 9

Living things are responsive to internal and external stimuli

Question 10

Define homeostasis

Answer 10

Living things maintain a stable internal environment

Question 11

Define excretion

Answer 11

Living things exhibit the removal of waste products

Question 12

define nutrition

Answer 12

living things exchange materials and gases with the environment

Question 13

define growth

Answer 13

living things can move and change shape/size

Question 14

explain how paramecium show response

Answer 14

it’s surrounded by small hairs called cilia which allow it to move

Question 15

expain how paramecium show nutrition

Answer 15

it engulf food via membranous feeding

Question 16

explain how paramecium show metabolism

Answer 16

food particles are enclosed within small vacuoles that contains enzymes for digestion

Question 17

explain how paramecium show excretion

Answer 17

solid wastes are removed via pores, pumping out wastes

Question 18

explain how paramecium shows homeostasis

Answer 18

essential gases enter and exit via diffusion

Question 19

explain how paramecium reproduce

Answer 19

divides by fission

Question 20

what is important in the limitation of cell size

Answer 20

SA/Vol ratio

Question 21

what do cell nedd to do to survive?

Answer 21

produce chemical energy, exchanging materials with the environment

Question 22

what is the rate of metabolism affected by?

Answer 22

larger cells need more energy to sustain essential functions

Question 23

how does SA/Vol ratio change with increasing cell size

Answer 23

as a cell grows, volume increase faster than surface are, leading to a decreased SA/Vol ratio

Question 24

what will happen if the metabolic rate exceeds the rate of exchange of vital materials and wastes?

Answer 24

if metabolic rate exceeds the rate of exchange of vital materials and water (low SA:Vol ratio), the cell will eventually die

Question 25

how does cells prevent the SA:Vol ratio becoming too low?

Answer 25

hence growing cells tend to divide and remain small in order to maintain a high SA:Vol ratio suitable for survival