Chapter 2– The Cell In Action

Section 1 – Exchange with the Environment

______________________________ - The movement from areas of high concentration

to areas of low concentration

______________________________ - The diffusion of water from areas where they are more concentrated to areas where they are

less concentrated.

______________________________ - a membrane that lets only certain substances

pass through.

Diffusion

Osmosis

Selectively permeable

•

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What happens to a red blood cell when it is put into a salty

solution?

What happens when a wilted plant is watered?

Water moves OUT, salt moves INCell gets SMALLER!!

Water moves IN. Cells gets LARGER!!

_________________________________________ - the movement of particles across a cell membrane without the use of energy. Particles move from an area of ______________ concentration to an area of _____________ concentration.

________________________________________ - the movement of particles across a cell membrane with the use of energy. Particles move from an area of ______________ concentration to an area of _____________ concentration.

Large particles move in to a cell by the process of ____________________________ and out of a cell by the process of _______________________. Both processes require the use of a sac called a __________________________.

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Passive transport

highlow

Active transport

lowhigh

endocytosisexocytosis

vesicle

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Chapter 2 – The Cell In Action

Section 2 – Cell Energy

Respiration and Photosynthesis

Photosynthesis – process in which autotrophs use light energy from the sun to produce food.

How does food store energy?

PHOTOSYNTHESIS– the process in which the plastids of plant cells take energy from the Sun, adds it to water and carbon dioxide, and changes it to food and oxygen.

H2O + CO2 + E C6H12O6+ O2

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carbon dioxide + C6H12O6

water + + oxygen Energy (ATP)

Photosynthesisre

acta

nts

products

Heterotrophs – organisms that can’t perform photosynthesis

So how do heterotrophs get their food?

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How do cells get energy from food?

Respiration – the process in which the mitochondria of cells takes food, adds it to oxygen, and changes it to water, carbon dioxide, and energy

C6H12O6 + O2 H2O + CO2 + E

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C6H12O6 carbon dioxide

+ + water oxygen + Energy (ATP)

Respiration

Respiration occurs in the mitochondria.

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AEROBIC RESPIRATION - Cellular respiration that takes place with oxygen present

ANAEROBIC FERMENTATION – energy can be taken from food

without oxygen present

WHAT IS FERMENTATION?

• Fermentation is the creation of energy without using oxygen

• Example: marathon running… lactic acid and yeast cells

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Chapter 2 – The Cell In Action

Section 3 – The Cell Cycle

The Cell Cycle

• The DNA in the nucleus of eukaryotic cells gets rolled into long rods called chromosomes

• In order for each cell to divide (reproduce) the DNA must get copied to make 2 new complete cells through a process called mitosis

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Chromosomes

• Make up of our DNA• Tight coils or rod like structures• Humans have 46 chromosomes of DNA in

EVERY single cell

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•cell is not dividing

• cell is growing, performing respiration, producing, photosynthesizing, doing whatever functions it is supposed to do

•At some point, the cell can’t diffuse fast enough and that signals the end of interphase

•At the very end of interphase, the chromatin makes an exact copy of itself in a process called DNA replication. 22

Interphase

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Mitosis• The part of a cell’s life cycle when the cell divides it nuclear contents

into 2 nuclei which are identical

•Mitosis consists of 4 steps:•Prophase

•Metaphase•Anaphase•Telophase

• all sub-cellular organelles disappear

• centrioles separate and move to opposite poles

• chromatin become chromosomes

• centrioles shoot off spindle fibers (short and long)

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1-Prophase

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chromosomes line up at the equator

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2-Metaphase

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• centromere splits

•sister chromatids attach to the short spindle fibers

•short spindle fibers shorten and bring the sister chromatids to opposite poles. 29

3-Anaphase

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• chromatids become chromatin (one at each pole)• spindle disappears• subcellular organelles reappear

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4-Telophase

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Cytokinesis

• The part of a cell’s life cycle when the cytoplasm divides into 2 cells which are identical

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Plant and Animal CytokinesisPlant cell-cell plate Animal cell-cleavage furrow

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Cytokinesis-mitosis is done!

• Last stage of cellular reproduction, the cell cycle– Cytoplasm splits apart, there are 2 new identical

cells

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Cytokinesis in Animal Cells• Cell membrane pinches in at equator

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• Cell membrane pinches in at equator

Cytokinesis in Plant Cells

• Cell plate forms at equator and grows out to the cell wall

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