Goal 2

The learner will develop an understanding of the physical,

chemical, and cellular basis of life

Main Topics

• Organic Compounds

• Structure and Function of Cells

• Organelles

• Cell Specialization and Communication

• Cell Transport

• Enzymes

• Cellular Respiration and Photosynthesis

Organic Compounds

• 4 organic compounds– “organic” = contains carbon = all living things

have organic compounds in them

– Carbohydrates– Lipids– Proteins– Nucleic Acids

Carbohydrates (Polysaccharides)

• Subunit (made of) = monosaccharides

• Function = immediate energy

• Examples: – Starch = energy storage for plants– Cellulose = makes up cell walls– Glycogen = energy storage for animals– Glucose = a simple sugar

Carbs Cont’

• Tests = – Starch is tested with

iodine

– Monosaccharides are tested with Benedicts Solution

Lipids

• Subunits = glycerol and fatty acids

• Function = long term energy storage

• Examples:– Fats– Waxes on plants (cuticle)

• Tests = brown paper bag test

Proteins

• Subunits = amino acids• Function = structure of tissues, transport

for cells• Examples:

– Insulin (hormones)– Hemoglobin (red blood cells)– Enzymes– Antigens/Antibodies

• Test = Biuret’s Reagent

Enzymes

• Speed up chemical reactions = catalysts

• Can be affected by pH or temperature = enzymes are very specific!

• Enzymes are reusable!

Lock and Key

Nucleic Acids

• Subunits = nucleotides

• Function = stores cellular information for cells

• Examples:– DNA and RNA

• Tests = NONE… all living things have DNA and RNA

Cell Organelles

• Nucleus = controls cell activity “brain”

• Plasma Membrane (aka cell membrane) = controls what enters and exits cell “gate keeper”

• Cell Wall = protects and supports some cells

• Mitochondria = provides energy (ATP) to cells “powerhouse”

Organelles, cont’

• Vacuoles = stores water, waste, food

• Chloroplast = site of photosynthesis, makes food for plant cells

• Ribosome = site of protein synthesis – where proteins are made

Microscope

• Total Magnification:– Ocular lens x objective lens– Ex:

• The microscope you are using has an ocular lens of 10x. The objective lens is on 60x. What is the total magnification?

Organization

• Unicellular = made of 1 cell (bacteria)

• Multicellular = made of many cells (us, plants, animals)

• Cells Tissues Organs Organ Systems Organism

Plant Cells Animal Cells

• Have cell walls made of cellulose outside of cell membrane

• Have chloroplasts and mitochondria

• Boxy shape• Green• 1 big vacuole

• No cell walls; just a cell membrane

• Mitochondria only• Round shape, more

flexible• Centrioles• Many small vacuoles

Cell Communication

• Chemical signals can be released by one cell to influence another cell– Ex: Hormones

• Chemicals attach to receptor proteins on cells and pass the message along

Cell Transport

• Cells must maintain homeostasis• Homeostasis = maintaining a stable internal

environment

– Regulate temperature = shiver or sweat– Blood glucose = insulin is released after

eating– Water = mouth becomes dry when thirsty,

eliminate water by urine

Cell Membrane

• The cell membrane maintains homeostasis in a cell by allowing only certain things in and certain things out!– Semi-Permeable or Selectively Permeable

• Structure = phospholipid bilayer

Two Types of Transport

• Passive Transport– NO ENERGY NEEDED– Goes from HIGH concentrations to LOW

concentrations– Ex: Diffusion and Osmosis, Faciliated Diffusion

• Active Transport– ENERGY is NEEDED!!– Goes from LOW concentrations to HIGH

concentrations

Diffusion - PASSIVE

• Diffusion = the movement of PARTICLES (solutes) from an area of high concentration to low concentration

• Concentration Gradient = when the sides are not equal

Osmosis - PASSIVE

• Osmosis = the movement of WATER from an area of high concentration to an area of low concentration

Water

Cells and Osmosis

• Water goes into cell = causes swelling

• Water leaves cell = causes shrinking

Osmosis Examples

• A cell is placed in a solution where there is 20% water outside and 80% water inside. Where does the water go? What happens to the cell?

• A cell has 40% glucose outside and 60% glucose inside. What happens?

Facilitated Diffusion - PASSIVE

• Facilitated Diffusion = diffusion through transport proteins

• Two proteins– Channel = does not change shape– Carrier = changes shape

ACTIVE Transport

• Active Transport = requires ENERGY!

• Can use carrier proteins

Active Transport, Cont’

• Endocytosis and Exocytosis are examples of active transport = require ENERGY– Endo- = taking IN of large molecules– Exo- = EXPELLING of large molecules

Cell Energy

• ATP is the source of energy for cells– ATP = A-P-P-P– ADP = A-P-P

• ATP becomes ADP by: losing a P = releases energy

• ADP becomes ATP by: gaining a P = stores energy

Cell Energy

Photosynthesis- Occurs in chloroplast- Occurs in plants- Makes food for plants

CO2 + H2O + light C6H12O6 + O2

** after plants make food in photosynthesis, the food is turned into energy during cellular respiration!

Cellular Respiration- Occurs in

mitochondria- Occurs in plants AND

animals- Turns food into

energy (ATP)

C6H12O6 + O2 CO2 + H2O+ ATP

Cellular RespirationAerobic- Occurs in mitochondria when oxygen is available- Makes 36 ATPs

Anaerobic- Occurs in mitochondria when oxygen is NOT available- Makes 2 ATP - AKA Fermentation

- 2 types: Alcoholic (makes Alcohol and CO2 – bread, beer) and Lactic Acid (makes lactic acid in your muscles)

A student tested different foods to determine which organic compounds were present. She based her results on the following information:

All four tests were performed on skim milk. The observations were that Benedict’s solution changed color and Biuret’s changed color. All other tests had a negative result. Which organic compounds were present in skim milk?

A. Sugar and Protein

B. Fat and Sugar

C. Sugar and Starch

D. Starch and Protein

Test Positive Reaction

Organic Compound Indicated

Brown paper Shiny spot fat

Benedict’s Solution

Color change Sugar

iodine Color change starch

Biuret’s solution

Color change protein