Chapter 2: Cell Processes and Energy Lesson 1: Photosynthesis Cells and Heredity Chapter 2: Cell Processes and Energy Lesson 1: Photosynthesis

Energy from the Sun All organisms get their energy from the food that they eat. Plants, algae, and some bacteria are able to make their own food from the sun’s energy. They are called producers, or autotrophs. Organisms that cannot produce their own food are called consumers, or heterotrophs.

Photosynthesis The process by which a cell captures energy in sunlight (where in the cell?) and uses it to make food. Chloroplasts/chlorophyll There are two stages in photosynthesis.

Photosynthesis – Stage 1 Capturing the sun’s energy: Occurs mostly in the leaves or green parts of the plant. Chlorophyll captures light energy and converts it to a form that can be used in stage 2. Water is broken down into oxygen (given off as waste) and hydrogen (used in stage 2).

Photosynthesis – Stage 2 Using energy to make food: Cells use H from stage 1, CO2 from the air, and sunlight to undergo a chemical reaction. After the chemical reaction, sugar is made and oxygen gas is released from the plant. Plants can use the sugar right away or store it as starch to use later.

Photosynthesis – Stage 2 Using energy to make food: Gas exchange (CO2 and O2) occurs in the stomata.

Photosynthesis

The Equation Light energy + CO2+ H2O glucose (sugar) + O2 Light energy + 6 CO2+ 6 H2O C6H12O6 + 6 O2 Energy, carbon dioxide, and water are reactants, sugar and oxygen are products.

Cells and Heredity Chapter 2: Cell Processes and Energy Lesson 2: Cellular Respiration & Fermentation

Cellular Respiration The continuous process by which cells obtain energy from glucose. Respiration means that oxygen is required for this process. There are two stages to cellular respiration.

Cellular Respiration – Stage 1 Glucose is broken into smaller molecules: Occurs in the cytoplasm Does not use oxygen Does not release much energy

Cellular Respiration – Stage 2 Small molecules are broken down further: Takes place in the mitochondria Requires oxygen Releases a great amount of energy

Cellular Respiration glucose (sugar) + O2  CO2+ H2O + energy C6H12O6 + 6 O2  6 CO2+ 6 H2O + energy Sugar and oxygen are the reactants, and energy, carbon dioxide, and water are products.

Cellular Respiration vs. Photosynthesis

Fermentation An energy releasing process that does not require oxygen. It releases much less energy than cellular respiration, but can be used by some organisms when oxygen is not present.

Types of Fermentation Alcoholic Fermentation Occurs in yeast and single-celled organisms. Produces alcohol, CO2, and energy.

Types of Fermentation Lactic Acid Fermentation Occurs when your body cannot replace oxygen in its cells as quickly as it is being used. Creates lactic acid, which causes a painful sensation in your muscles. The pain goes away when oxygen is returned.

Chapter 2: Cell Processes and Energy Lesson 3: Cell Division Cells and Heredity Chapter 2: Cell Processes and Energy Lesson 3: Cell Division

Functions of Cell Division Cell division allows organisms to: Grow/Develop Repair Reproduce

The Cell Cycle During the cell cycle, a cell grows, prepares for division, and divides into two new (daughter) cells. There are three main stages: Interphase Mitosis (prophase, metaphase, anaphase, and telophase) cytokinesis

The Cell Cycle

Interphase Cell grows to its full size and produces organelles and enzymes. Cell makes an exact copy of its DNA through replication, which results in two identical sets of chromosomes. Cell prepares to divide. Animal cells duplicate centrioles.

Mitosis Cell’s nucleus divides into two new nuclei and one set of DNA is given to each new cell. Chromosomes are made of two exact chromatids. A centromere holds the chromatids together, but eventually allows them to move apart.

Mitosis Prophase: Metaphase: DNA goes from its loose form into chromosomes. The membrane around the nucleus disappears. Centrioles separate and spindle fibers form. Metaphase: Chromosomes line up in center of the cell and attach to spindle fibers. Nucleus disappears.

Mitosis Prophase & Metaphase

Mitosis Anaphase: Telophase: Centromeres split and chromatids are pulled apart. The cell stretches out as chromosomes move to opposite ends. Telophase: Nuclear membrane forms around each set of chromosomes. Cell begins to divide into two daughter cells.

Mitosis Anaphase & Telophase

Cell Division

Cytokinesis The cytoplasm divides and two new cells are formed. In animal cells: The cell is pinched together to separate into two new cells. In plant cells: A cell plate forms across the cell, dividing the cell into two parts. The cell plate eventually helps form the new cell walls for the two daughter cells.

Cytokinesis