Chapter 8Cellular Transport and the Cell Cycle

Section 8.1 Cellular Transport

• Explain how the processes of diffusion, passive transport, and active transport occur and why they are important to cells.

• Predict the effect of a hypotonic, hypertonic, or isotonic solution on a cell.

Osmosis: Diffusion of Water

• The diffusion of water

across a selectively

permeable membrane（选择性透过膜） is called osmosis

( 渗透 ). （ p. 195）

• Isotonic-

concentration inside and

outside the cell are equal

(equilibrium)

• Hypotonic

concentration is low on the

outside and high on the

inside

• Hypertonic

concentration is high on the

outside and low on the

inside

Passive Transport (被动运输 )（ p.198 ） - no energy needed

• Simple diffusion（简单扩散）

Passive Transport (被动运输 )

Facilitated diffusion(协助扩散）

(specific substance)

Passive Transport (被动运输 )

Facilitated diffusion(协助扩散）

(specific substance)

Active Transport （主动运输）（ p. 199)- energy is needed

• Creates Conc. gradients

p. 199

Transport of Large Particles

• Endocytosis

Cell folds around large particle and

pulls it in; plasma membrane makes

vacuole

• Exocytosis

Vacuole fuses with plasma membrane

and release large particles

Cell Size Limitations (p. 201)• Diffusion limits cell size

– too big and it will take too long for things

for move around the cell

• DNA limits cell size

– Too big and it will take too long to make

the proteins needed

• Surface area-to-volume ratio

– Too big and not enough surface area to

take in nutrients and release waste

Section 8.2Cell Growth and Reproduction

• Sequence the events of the cell cycle.

• Relate the function of a cell to its organization in tissues, organs, and organ systems.

Cell Reproduction (p. 203)

• Cell division is the process by

which new cells are produced

from one cell

The Cell Cycle (p.204&206)

p.205

Mitosis (有丝分裂 )

• Mitosis is divided into four phases （ p. 207）

– Prophase （前期）– Metaphase（中期）– Anaphase（后期）– Telophase（末期）

Prophase

• Nucleus break apart• DNA coils into Chromosomes

which are visible

Metaphase

• Spindle fibers attach to the centromeres of the chromosomes

• Chromosomes are moved to the center of the cell

Anaphase

• Centromeres split apart and sister chromatids move to opposite sides of the cell

Telophase

• Reverse of Prophase• Nucleus reappears and

chromosomes start to unwing

Cytokinesis （胞质分裂， P209）

Results of Mitosis

• Mitosis results in two cells that are identical to the original, parent cell.

P 218

Section8.3 Control of the Cell Cycle

• Describe the role of enzymes in the regulation of the cell cycle.

• Distinguish between the events of a normal cell cycle and the abnormal events that result in cancer.

• Identify ways to potentially reduce the risk of cancer.

Normal Control of the Cell Cyclep. 211

• Proteins and enzymes control the cell cycle

• Proteins are regulated by genes (sections of DNA)

• Mutations in genes can lead to cancer

Cancer: A Mistake in the Cell Cycle

• Cancer

cells have a

very short

interphase.

• Grow and

divide very

fast

The causes of cancer （ p. 212）

• Genetic factors

• Environmental factors

– cigarette smoke

– air and water pollution

– exposure to ultraviolet

radiation from the sun

– viral infections (HPV)

Cancer prevention （ p.213）

• Diets high in fiber

• Fruits, vegetables, and grain

products – carotenoids(类胡萝卜素 )– vitamins A, C,and E, – calcium

• Daily exercise and not using tobacco

That’s all