Chapter 3 CELL PROCESSES AND ENERGY

Chapter 3 CELL 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 - C Hydrogen - H Oxygen - O Nitrogen - N Phosphorus -P Sulfur -S

Compounds Compounds = Two or more elements chemically combined Molecule= Smallest unit of a compound Compounds found in the body: Water (H 2 O) 2/3 of the body Needed for chemical reactions within the cells Carbon Dioxide (CO 2 ) 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: fruit 2. 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

Proteins Meat, 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 Acids Contain 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 Passive Osmosis transport Active 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 Transport Movement 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: Photosynthesis Process by which cells capture energy from sun and uses it to make food Autotrophs like plants use photosynthesis 6 CO 2 + 6 H 2 O C 6 H 12 O 6 + 6 O 2 Carbon dioxide + Water Glucose + Oxygen = requires light energy 2 stages 1. 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 2 nd stage

Stage 2: Using Energy to make food Cell uses captured energy to make sugars Needs H 2 O (via roots) and CO 2 (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: Respiration Respiration Process by which cells obtain energy from glucose Aka. Cellular Respiration Must use respiration (or breathing in O2) to occur Two Stages 1 st stage- occurs in cytoplasm Molecules of glucose broken down into smaller molecules 2 nd stage- occurs in mitochondria Small molecules broken down into even smaller molecules Oxygen needed and LOTS of ENERGY released

Respiration Equation C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + ENERGY *Photosynthesis and Respiration are a CYCLE

Fermentation Energy-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: Interphase Period 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