Chapter 2: The Cell in Action Sections 1-3 Pages 32-49.

Chapter 2:

The Cell in Action

Sections 1-3Pages 32-49

Diffusion

• The movement from areas of high concentration (crowded) to lower concentration (not crowded)

• Diffusion happens within and between living cells, requires no energy

Diffusion Animation

• http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html

Osmosis

• The diffusion of water molecules through cell membranes

• Semi permeable- only some substances can pass through

Osmosis and the Animal Cell

Osmosis and the Plant Cell

Osmosis Animation

• http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

Moving Small Particles

• Passive TransportThe movement of particles across the cell membrane without the use of energy

• Diffusion and Osmosis are examples

Moving Small Particles

• Active Transport Low to high concentration, requires energy because it works against the flow of particles (example-gravity, going up hill)

• http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

Moving Large Particles

• The active-transport process by which a cell surrounds a large particle, such as a large protein, and encloses the particle in a vesicle to bring the particle into the cell is called endocytosis

Vesicles are sacs formed from pieces of cell membrane.

Moving Large Particles

• When large particles, such as wastes, leave the cell, the cell uses an active-transport process called exocytosis.

• During exocytosis, a vesicle forms around a large particle within the cell. The vesicle carries the particle to the cell membrane.

• The vesicle fuses with the cell membrane and releases the particle to the outside of the cell.

Endo and Exocytosis

• http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120068/bio02.swf::Endocytosis%20and%20Exocytosis

Cell Energy

Autotrophs• An organism that makes its

food through the process of photosynthesis.

• Also known as “producers”

Heterotrophs• An organism that can not

make its own food, so it eats other organisms or plants.

• Also known as “consumers”

Energy Roles

• Each organism in an ecosystem fills the energy role of either producer, consumer or decomposer.

Energy Roles http://www.glencoe.com/sites/common_assets/science/virtual_labs/CT06/CT06.html

• Producer• An organism

that can make its own food.

• Producers are the source of all food in an ecosystem.

• Plants, algae and some bacteria.

• Consumer• An organism

that feeds on other organisms.

• Herbivore• Carnivore • Omnivore-

human• Scavenger

• Decomposer• An organism

that breaks down wastes and dead organisms.

• Nature’s recyclers

• Mushrooms and bacteria

Photosynthesis

• During photosynthesis, plants and some organisms use energy from the sun to convert carbon dioxide and water into oxygen and sugars.

• Plants use the pigments called chlorophyll (which makes plants green) located in the chloroplasts to change the carbon dioxide, water and sunlight to oxygen and sugar

Photosynthesis

• Stage 1: Capturing the sun’s energy, Chloroplasts in plant cells capture energy from the sunlight

• Stage 2: The captured light energy is used to produce sugars and oxygen from water and carbon dioxide.

Photosynthesis

carbon dioxide + water + sunlight = sugar + oxygen

6CO2 + 6H2O + sunlight = C6 H12 O6 + 6O2

Cellular Respiration

• During cellular respiration, cells break down simple food molecules such as sugar and release the energy they contain

• Many cells use oxygen to break down these food molecules

• Most of the energy released maintains body temp, some is used to form ATP.

Cellular Respiration

• Stage 1: In the cytoplasm, molecules of glucose are broken down into smaller molecules. Oxygen isn't involved and only a small amount of energy is released.

• Stage 2: Takes place in the mitochondria, the small molecules are broken down even smaller. These chemical reactions require oxygen and release a lot of energy. This is why the mitochondria are called the “powerhouse” of the cell.

Cellular Respiration

• What is the difference between cellular respiration and respiration (breathing)?

• Cellular respiration is a chemical process by which cells produce energy from food. Respiration or breathing supplies the body with raw materials needed for cellular respiration.

Cellular Respiration

Does this look like the Carbon Cycle?

Comparing Photosynthesis and Cellular Respiration

Fermentation

• Provides energy for cells without using oxygen.

• Alcoholic fermentation: when yeast and some other single celled organisms break down sugar

• Lactic acid fermentation: takes place in our bodies when you exercise and feel that painful sensation in your muscles because you were using up oxygen faster than it can be replaced

Life of a Cell- the Cell Cycle

• The cell cycle begins when the cell is formed and ends when the cell divides and forms new cells.

• Before it can divide, it must make a copy of its DNA.

• DNA is organized into chromosomes. This ensures that each new cell made will be an exact copy of its parent cell.

Making more Prokaryotic Cells

• Less complicated than Eukaryotic cells.

• These Prokaryotic cells (like bacteria) go through binary fission.

• Binary fission is when the cell splits into two, resulting in two cells.

Eukaryotic cells and their DNA

• More complex • Contain more DNA• Humans have 46

chromosomes, 23 pairs, homologous chromosomes

• The number of chromosomes is not always related to the complexity of organisms.

Making more Eukaryotic Cells- 3 stages

• Stage 1: Interphase-The cell grows and copies its

organelles.After each chromosome is

duplicated, the copies are called chromatids.

Chromatids are held together at the centromere.

The chromatids join and twist, condensing into a X shape.

Cell Cycle

• http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__control_of_the_cell_cycle.html

Making more Eukaryotic Cells

• Stage 2: Mitosis-Chromatids separate.This ensures that each new cell

receives a copy of each chromosome.

During mitosis, one copy of the DNA is distributed into each of the two daughter cells.

There are four phases of mitosis- Prophase, Metaphase, Anaphase, and Telophase

Phases of Mitosis

• Phase 1. Prophase: Nuclear membrane dissolves. Chromosomes condense into rod like structures.

Phases of Mitosis

• Phase 2. Metaphase: The chromosomes line up along the equator of the cell. Homologous chromosomes pair up.

Phases of Mitosis

• Phase 3. Anaphase: The chromatids separate and move to opposite sides of the cell.

Phases of Mitosis

• Phase 4. Telophase: A nuclear membrane forms around each set of chromosomes, and the chromosomes unwind. Mitosis is complete.

Making more Eukaryotic Cells

• Stage 3: CytokinesisDuring this stage the

cytoplasm divides. The organelles are distributed into each of the two new cells.

Cytokinesis is different in animal cells than plant cells because plant cells have cell walls.

Plant cells form a cell plate during cytokinesis.

Mitosis and Cytokinesis

• http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__mitosis_and_cytokinesis.html

Time a Cell Spends in Phases of Mitosis

Cell Cycle Time Chart

Interphase and Mitosis

• Interphase in the cell cycle is like childhood and adolescence in the human cycle, because this is the time of growth and maturity. During interphase, a cell grows to its full size. NO cell division occurs.

• Mitosis is like adulthood because humans reproduce in this stage. During mitosis, the nucleus divides to form new cells.