Biology Assessment #1 Flashcards
Includes: Ecology models (pyramids, webs, chains), Macromolecules (and enzymes), Nitrogen (How it gets into plants)
Macromolecules
Large complex molecules essential for life.
What are the four main types of macromolecules?
Carbohydrates, Proteins, Lipids, and Nucleic Acids
What do carbohydrates do?
Provide energy
What do proteins do?
Perform a variety of functions including catalyzing reactions (enzymes), signaling, and structural support
What do lipids do?
Store energy and make up cell membranes
What do nucleic acids do?
Store and transmit genetic information (DNA and RNA)
What is a monomer?
A small, basic molecular unit that can bind chemically to other monomers to form a larger structure. It is like a single “building block” that can join together with others to form complex molecules.
What is a polymer?
A large molecule made up of repeating units of monomers linked together through chemical bonds. Polymers are long chains or structures formed from these smaller monomers, and they can be natural or synthetic.
Monomers of Carbohydrates
Monosaccharides (e.g., glucose)
Polymers of Carbohydrates
Polysaccharides (e.g., starch, glycogen, cellulose)
Functions of Carbohydrates
Primary energy source (glucose used in cellular respiration)
Structural support in plants (cellulose)
Monomers of Proteins
Amino acids (20 different kinds)
Polymers of Proteins
Polypeptides, which fold into complex 3D structures to form functional proteins
Functions of Proteins
Enzymes: Proteins that catalyze biochemical reactions by lowering the activation energy
Structural support (e.g., collagen), transport (e.g., hemoglobin), defense (e.g., antibodies)
Monomers of Lipids
Fatty acids and glycerol
Polymers of Lipids
Triglycerides, phospholipids (key component of cell membranes), and steroids
Functions of Lipids
Long-term energy storage.
Insulation and protection.
Making up cell membranes (phospholipids).
Monomers of Nucleic Acids
Nucleotides (sugar, phosphate group, nitrogenous base)
Polymers of Nucleic Acids
DNA (stores genetic info) and RNA (transmits genetic info and helps in protein synthesis)
Enzymes
Proteins that speed up chemical reactions.
Enzyme mechanism
Works by lowering the activation energy of a reaction, making it easier for reactions to occur.
Active Site
The part of the enzyme where the substrate binds and the reaction occurs.
Enzyme-Substrate Complex
The enzyme binds to the substrate, facilitating the reaction, then releases the product.
Enzyme Specificity
Each enzyme is specific to a particular substrate due to the shape of its active site.
Factors Affecting Enzyme Activity
Temperature: Too high or too low temperatures can denature the enzyme, altering its shape and function.
pH: Each enzyme works best at a specific pH; deviation can denature the enzyme.
Concentration: Higher enzyme or substrate concentration increases reaction rate until saturation.
Key processes of Enzymes
Dehydration Synthesis: Enzymes help build larger molecules (polymers) by removing water.
Hydrolysis: Enzymes break down polymers into monomers by adding water (e.g., during digestion).
Denature
When an enzyme loses its specific three-dimensional structure, rendering it unable to perform its biological function. Enzymes are proteins, and their function depends on their specific shape, particularly the shape of the active site where the substrate binds. When an enzyme is denatured, its structure is altered, which typically results in the loss of its ability to bind to substrates and catalyze reactions.
Types of ecology models
Pyramids, Webs, Chains
Food Chain
A linear sequence showing how energy and nutrients flow from one organism to another.
Levels of a food chain
Producers, Primary Consumers, Secondary Consumers, Tertiary Consumers
Food Web
A complex network of interconnected food chains that show how energy flows through an ecosystem.
Why are food webs important?
Represents the diverse feeding relationships in an ecosystem, showing how different species are interdependent.
Energy Pyramid
A graphical representation of energy flow in an ecosystem.
Trophic levels
Producers (base with the most energy) → Primary Consumers → Secondary Consumers → Tertiary Consumers (top with the least energy).
Energy Transfer (between trophic levels)
Only about 10% of the energy is transferred from one level to the next; the rest is lost as heat.
Importance of Nitrogen
Nitrogen is a critical component of amino acids (proteins), nucleotides (nucleic acids), and chlorophyll (in plants).
Where does Nitrogen come from?
Nitrogen makes up 78% of Earth’s atmosphere, but most organisms cannot use atmospheric nitrogen (N₂) directly.
What is the Nitrogen Cycle?
Nitrogen Fixation, Nitrification, Assimilation, Ammonification, Denitrification
Nitrogen Fixation
Nitrogen-fixing bacteria in soil and plant root nodules (legumes) convert atmospheric nitrogen (N₂) into ammonia (NH₃), which can be used by plants.
Nitrification
Soil bacteria convert ammonia into nitrites (NO₂⁻) and then into nitrates (NO₃⁻), which plants absorb through their roots.
Assimilation
Plants take up nitrates and ammonia from the soil and use them to make proteins and other nitrogen-containing compounds.
Ammonification
Decomposers (bacteria and fungi) break down dead organisms and waste, converting organic nitrogen back into ammonia, which can re-enter the soil.
Dentrification
Denitrifying bacteria convert nitrates back into nitrogen gas (N₂), releasing it back into the atmosphere, completing the nitrogen cycle.
How plants get Nitrogen
Absorption: Plants absorb nitrogen from the soil primarily in the form of nitrates (NO₃⁻) and ammonium (NH₄⁺).
Symbiotic Relationships: Some plants (especially legumes) form symbiotic relationships with nitrogen-fixing bacteria that live in their root nodules, directly receiving usable nitrogen.
