Cells: Cell Theory

Question 1

Cell Theory

Answer 1

a unifying concept

1. All living things are made up of cells or cell products
2. Cells are the smallest structural and functional unit of living tings
3. Cells contain DNA (genetic information/heredity material)
4. All cells arise from pre-existing cells

Question 2

Characteristics of Living Things

Answer 2

1. movement
2. respiration
3. sensitivity to stimuli (responses)
4. growth
5. reproduction
6. excretion of waste/synthetics
7. require nutrition
8. chemically different internal composition to external environment

Question 3

Cell Size

Answer 3

SA:Vol

• as cell size increases, SA:Vol ratio decreases
• cells obtain nutrients & remove waste products through the cell membrane… as size increase, proportionally less SA, therefore decrease in efficiency
• DNA may only be able to exert an influence over a finite volume

Question 4

Cells & Technology

Answer 4

• light microscopes: easily prepare sample, observe living material & movement, larger field of view (magnify, study structure & organelles)
• electron microscopes:
• -transmission (cross-section) best for structure & organelles
• -scanning (3D image, surface)