Chapter 3CELL PROCESSES AND ENERGY

Section 1: Chemical Compounds in Cells

Elements= Any substance that cannot be broken down into a simpler form

◦ Made up of only one kind of atom◦ Found in the body

Carbon - CHydrogen - HOxygen - ONitrogen - NPhosphorus -PSulfur -S

CompoundsCompounds = Two or more elements chemically combined•Molecule= Smallest unit of a compound

•Compounds found in the body:• Water (H2O)

• 2/3 of the body

• Needed for chemical reactions within the cells

• Carbon Dioxide (CO2)

•Organic vs. Inorganic Compounds• Organic- contain carbon

• Inorganic- do not contain carbon

• Examples: water, table salt

Organic Compounds in Living Things

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic Acids

Carbohydrates•Energy-rich compounds

•Two Types 1. Simple Sugars- Building blocks for starches;

includes glucose, fructose Example: fruit2. Complex- Starches

Ex: vegetables, potatoes, rice,pasta, bread

•Make up some cell parts• Cellulose is found in cell walls of plants• Carbs are also found in cell membranes

Lipids•Includes Fats, Oils, waxes

•Contain even more energy than carbs

•Cells contain lipids for long-term energy

•Main ingredient of cell membranes

ProteinsMeat, eggs, fish, nuts, beans

Structure:

◦ Made up of chains of Amino Acids- the building blocks of proteins

◦ 20 kinds of AA can combine in different combinations

Function:

◦ Make up organelles

◦ Make enzymes- speed up chemical reactions

◦ EX: Saliva breaks down carbohydrates to sugars in the mouth

Nucleic AcidsContain instructions that cells need to do jobs

Two types:

◦ DNA

◦ Genetic material that carries info about organism

◦ Passes on info to offspring

◦ Found in chromatin in nucleus

◦ RNA

◦ Used for Protein production

◦ Found in cytoplasm and in nucleus

Section 2: The Cell in its Environment

Selectively Permeable

◦ Ability of some substances to pass through the membrane while others cannot

◦ Let in oxygen and food molecules

◦ Move out waste materials

Three methods for material movement

◦ Diffusion

◦ Osmosis

◦ Active Transport

Passive

transport

1. Transport Proteins

2. Transport by Engulfing

Diffusion

•Main method of small molecule movement across cell membrane

•Move from area of high to low concentration

•Collisions cause molecules to spread out

•Passive transport- NO energy required;

meaning NO ATP from the mitochondria is needed

Osmosis Diffusion of water through cell membrane

Passive transport- NO energy required

Active TransportMovement of materials using cellular energy (ATP)

1. Transport Proteins “pick up” molecules and carry them in and out of cell

2. Transport by Engulfing

◦ Cell membrane surrounds a particle and brings it in

Section 3: PhotosynthesisProcess by which cells capture energy from sun and uses it to make food

Autotrophs like plants use photosynthesis

6 CO2 + 6 H2O C6H12O6 + 6 O2◦ Carbon dioxide + Water Glucose + Oxygen

◦ = requires light energy

2 stages1. Capturing the sun’s energy

2. Using energy to make food

Stage 1: Capturing the Sun’s Energy

Mostly occurs in the chloroplasts in leaves

Pigment- makes leaves green ◦ Responsible for absorbing light

◦ Chlorophyll- main pigment in photosynthesis

Uses captured light as energy for 2nd stage

Stage 2: Using Energy to make food

Cell uses captured energy to make sugars

Needs H2O (via roots) and CO2 (via stomata)

Materials move to chloroplasts

Chemical reactions result in glucose and oxygen production

Glucose is used by plant for energy

Oxygen is released back out into atmosphere

Section 4: RespirationRespiration

◦ Process by which cells obtain energy from glucose

◦ Aka. Cellular Respiration

◦ Must use respiration (or breathing in O2) to occur

Two Stages

1st stage- occurs in cytoplasm

◦ Molecules of glucose broken down into smaller molecules

2nd stage- occurs in mitochondria

◦ Small molecules broken down into even smaller molecules

◦ Oxygen needed and LOTS of ENERGY released

Respiration EquationC6H12O6 + 6 O2 6 CO2 + 6 H2O + ENERGY

*Photosynthesis and Respiration are a CYCLE

FermentationEnergy-releasing process that does not require oxygen

Two types:◦ Alcoholic fermentation (yeasts)

◦ Lactic Acid Fermentation (painful muscles)

Section 5: Cell Division

THREE STAGES

◦ Interphase

◦ Mitosis

◦ Cytokinesis

Stage 1: InterphasePeriod before cell division

Longest phase of cell cycle

3 steps◦ Cell grows

◦ Replication

◦ Cell makes a copy of its DNA

◦ Prepares to divide into 2 cells

Stage 2: Mitosis

Mitosis = Division of the Nucleus◦ ONE copy of the DNA is distributed

into each of the two daughter cells

1. Chromatin condenses into chromosomes

2. Cell stretches out

3. New structures moves to ends of cell

Stage 3: Cytokinesis

Cytoplasm divides

Parent cell becomes two daughter cells

In animal cells:

◦ Cell membrane squeezes around middle and cytoplasm pinches into two cells

In plant cells:

◦ Cell wall cannot squeeze together so a cell plate forms in the middle and splits cell into 2 new cells