Living Environment Regents Exam Review - Unit 3

Unit 3

biochemistry

1. living things are made of organic compounds, organic compounds always contain the elements carbon and hydrogen, but they may also contain oxygen, nitrogen, or phosphorous

2. the most important INORGANIC compound is WATER

3. there are 4 types of organic compounds: carbohydrates, lipids, proteins, and nucleic acids

4. living things are made of ORGANIC COMPOUNDS, however, inorganic compounds such as O2 are also necessary for living things to maintain homeostasis and stay alive

organic compounds

• types:

  • carbohydrates

  • lipids (fats)

  • proteins

  • nucleic acids

• are either made by organisms (like producers) or obtained by other organisms (like consumers)

• in order to be used, they must first be DIGESTED (hydrolysis) or broken down into their building blocks so that they can pass through the cell membrane and be used for metabolic activities

• organisms will then re-assemble the building blocks into the compounds necessary for their own survival (this is known as SYNTHESIS)

carbohydrates

• elements: C, H, O

• building block/end products of digestion: C6H12O6, glucose, simple sugars, monosaccharides

• functions: provide energy

• examples: glucose, starch

lipids (fats)

• elements: C, H, O

• building block/end products of digestion: fatty acids, glycerol

• functions: stored energy, insulation/protection, cell membrane

• examples: phospholipids, saturated fat, cholesterol

proteins

• elements: C, H, O, N, S

• building block/end products of digestion: amino acids

• functions: major structural components (see examples)

• examples: enzymes, hormones, antigens, antibodies, receptors

nucleic acids

• elements: C, H, O, N, P

• building block/end products of digestion: nucleotides

• functions: genetic information, control cell metabolism, protein synthesis

• examples: DNA, RNA

enzymes

• are organic catalysts (proteins) that control the rate or SPEED of a chemical reaction

• all chemical reactions in an organism (cell respiration, photosynthesis, digestion, etc.) are controlled by the action of enzymes

• have a SPECIFIC SHAPE which determines to what molecules the enzyme can bind or react with - this is called specificity (enzymes bind to substrates)

• enzymes can be recycled (they are used over and over again)

• when enzymes are denatured (they lose their shape) which means they can no longer bind to the substrate so reactions will slow down or stop

factors that affect enzymes

• temperature

  • too hot can cause enzymes to denature

• pH

  • too high or low can cause enzymes to denature

photosynthesis

• Who: plants, algae, and blue-green bacteria (autotrophs & heterotrophs)

• What: using energy from the sun to convert inorganic compounds from the environment (CO2 and H2O) into glucose (C6H12O6) which is a source of energy

• Where: in the chloroplast of plant cells

• Why: to provide food (glucose) to the plant, to provide a source of food (organic compounds) for animals and other consumers or heterotrophs, and as a source of oxygen (O2) in our atmosphere

• When: takes place only during daylight

• Equation: CO2 + H2O + light, chlorophyll, & enzymes = C6H12O6 + 6H2) + 6O2

cell respiration

• Who: ALL ORGANISMS (including plants) (heterotrophs)

• What: transferring energy stored in glucose to a form of energy that can be used by the cell called ATP (ATP is used to carry out metabolic activities/basic life processes - without it cells will die)

• Where: in the mitochondria of cells (cells that do a lot of work like muscle and nerve cells, have a lot of mitochondria because they need more energy)

• Why: to provide a usable form of energy (ATP) and to supply CO2 to plants for photosynthesis

• When: takes place all the time

• Equation: C6H12O6 + O2 + enzymes = CO2 + H2O + 36 ATP

equations for cell respiration

• Word equation: glucose + oxygen —> carbon dioxide + water + energy

• Chemical equation: C6H12O6 + O2 → CO2 + H2O + 36 ATP

equations for photosynthesis

• Word equation: (light) carbon dioxide + water —> glucose + oxygen + water

• Chemical equation: CO2 + H2O —> C6H12O6 + O2 + H2O