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
