Exam 1 Flashcards
What is the definition of information?
Information is data that is organized in a meaningful way and can be used to communicate, make decisions, or regulate processes.
What is biological information?
Biological information is data stored, transmitted, and processed within living systems to guide cellular functions and organismal traits.
Name two examples of biological information.
1) DNA sequences that encode proteins, 2) Hormonal signals regulating body processes.
How does biological information flow from DNA to protein?
DNA → RNA (transcription) → Protein (translation).
List the levels of biological organization from smallest to largest.
Molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere.
Give an example of biological information at the cellular level.
Gene expression regulating cell differentiation.
What are the four most essential elements for life?
Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N).
Draw and label an atomic structure with protons, neutrons, and electrons.
(Self-made drawing)
What are the three main types of chemical bonds?
Ionic, covalent, and hydrogen bonds.
What determines how an atom forms bonds?
The number of valence electrons in the outer shell.
How do valence electrons influence bond formation?
Atoms gain, lose, or share electrons to complete their valence shells, forming bonds.
What is the difference between an element and a compound?
An element is a pure substance with one type of atom, while a compound is made of two or more elements bonded together.
Identify the bond types in the molecule H₂O.
Polar covalent bonds between hydrogen and oxygen, with hydrogen bonding between water molecules.
How does water’s polarity affect its properties?
It allows for hydrogen bonding, making water an excellent solvent and giving it cohesion, adhesion, and high heat capacity.
Draw a water molecule and label its partial charges.
(Self-made drawing)
Why does water form hydrogen bonds?
The partial negative charge on oxygen attracts the partial positive charge on hydrogen of another molecule.
Name another molecule that forms hydrogen bonds and its significance.
DNA; hydrogen bonds between nitrogenous bases stabilize the double helix.
What determines whether a molecule is hydrophobic or hydrophilic?
The presence of polar or charged regions makes it hydrophilic; nonpolar regions make it hydrophobic.
Why is carbon considered versatile in biology?
It forms four covalent bonds, allowing diverse complex molecules.
Name three common functional groups in biological molecules.
Hydroxyl (-OH), Carboxyl (-COOH), Amino (-NH₂).
What are the four biological macromolecules?
Carbohydrates, lipids, proteins, nucleic acids.
What reaction links monomers into polymers?
Dehydration synthesis (condensation reaction).
What reaction breaks down polymers?
Hydrolysis.
What are nucleic acids made of?
Nucleotides containing a sugar, phosphate, and nitrogenous base.
What are the two main types of nucleic acids?
DNA and RNA.
Compare DNA and RNA in terms of structure.
DNA: double-stranded, deoxyribose sugar, thymine; RNA: single-stranded, ribose sugar, uracil.
What does ‘complementary’ mean in nucleic acid strands?
Bases pair specifically (A with T/U, G with C) through hydrogen bonds.
Given the DNA strand 5’-ATCGG-3’, what is its complementary sequence?
3’-TAGCC-5’.
Name two major functions of proteins in living systems.
Catalysis (enzymes), structural support (collagen).
What are the basic components of an amino acid?
Amino group (-NH₂), carboxyl group (-COOH), R-group (side chain).
How are amino acids linked to form proteins?
By peptide bonds through dehydration synthesis.
How does protein structure relate to function?
A protein’s shape determines its ability to interact with other molecules.
What are the four levels of protein organization?
Primary, secondary, tertiary, quaternary.
What bonds stabilize each level of protein structure?
Primary: peptide bonds; Secondary: hydrogen bonds; Tertiary: hydrogen, ionic, disulfide, hydrophobic interactions; Quaternary: same as tertiary.
What happens if a mutation alters a protein’s amino acid sequence?
It may disrupt protein folding and function at multiple structural levels.
What are lipids primarily made of?
Carbon, hydrogen, and oxygen, with mostly nonpolar characteristics.
How do lipids differ from proteins and nucleic acids?
They are not polymers and are primarily hydrophobic.
Describe the structure of a phospholipid.
Hydrophilic head (phosphate group) and two hydrophobic fatty acid tails.
What is the role of biological membranes?
They regulate the movement of substances in and out of cells.
How do small, nonpolar molecules cross membranes?
By simple diffusion.
How do large or charged molecules cross membranes?
Through facilitated diffusion or active transport.
Why do phospholipids form bilayers in water?
Hydrophilic heads face water, and hydrophobic tails face inward, avoiding water.
Identify the bond type in the fatty acid tails of a phospholipid.
Nonpolar covalent bonds.
What determines whether a lipid is solid or liquid at room temperature?
The presence of saturated (solid) or unsaturated (liquid) fatty acids.
What are steroids, and why are they important?
Lipids with a four-ring structure; they function as hormones (e.g., cholesterol, testosterone).
Predict how an amino acid with a charged R-group will interact with water.
It will be hydrophilic and dissolve in water.
Why are enzymes important for biological reactions?
They speed up reactions by lowering activation energy.
What happens when a protein denatures?
It loses its shape and function due to environmental changes (e.g., heat, pH).
What is an example of a transport protein?
Hemoglobin, which carries oxygen in the blood.
What is ATP, and why is it important?
Adenosine triphosphate; it stores and transfers energy for cellular processes.
