Exam 1

Question 1

What is the definition of information?

Answer 1

Information is data that is organized in a meaningful way and can be used to communicate, make decisions, or regulate processes.

Question 2

What is biological information?

Answer 2

Biological information is data stored, transmitted, and processed within living systems to guide cellular functions and organismal traits.

Question 3

Name two examples of biological information.

Answer 3

1) DNA sequences that encode proteins, 2) Hormonal signals regulating body processes.

Question 4

How does biological information flow from DNA to protein?

Answer 4

DNA → RNA (transcription) → Protein (translation).

Question 5

List the levels of biological organization from smallest to largest.

Answer 5

Molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere.

Question 6

Give an example of biological information at the cellular level.

Answer 6

Gene expression regulating cell differentiation.

Question 7

What are the four most essential elements for life?

Answer 7

Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N).

Question 8

Draw and label an atomic structure with protons, neutrons, and electrons.

Answer 8

(Self-made drawing)

Question 9

What are the three main types of chemical bonds?

Answer 9

Ionic, covalent, and hydrogen bonds.

Question 10

What determines how an atom forms bonds?

Answer 10

The number of valence electrons in the outer shell.

Question 11

How do valence electrons influence bond formation?

Answer 11

Atoms gain, lose, or share electrons to complete their valence shells, forming bonds.

Question 12

What is the difference between an element and a compound?

Answer 12

An element is a pure substance with one type of atom, while a compound is made of two or more elements bonded together.

Question 13

Identify the bond types in the molecule H₂O.

Answer 13

Polar covalent bonds between hydrogen and oxygen, with hydrogen bonding between water molecules.

Question 14

How does water’s polarity affect its properties?

Answer 14

It allows for hydrogen bonding, making water an excellent solvent and giving it cohesion, adhesion, and high heat capacity.

Question 15

Draw a water molecule and label its partial charges.

Answer 15

(Self-made drawing)

Question 16

Why does water form hydrogen bonds?

Answer 16

The partial negative charge on oxygen attracts the partial positive charge on hydrogen of another molecule.

Question 17

Name another molecule that forms hydrogen bonds and its significance.

Answer 17

DNA; hydrogen bonds between nitrogenous bases stabilize the double helix.

Question 18

What determines whether a molecule is hydrophobic or hydrophilic?

Answer 18

The presence of polar or charged regions makes it hydrophilic; nonpolar regions make it hydrophobic.

Question 19

Why is carbon considered versatile in biology?

Answer 19

It forms four covalent bonds, allowing diverse complex molecules.

Question 20

Name three common functional groups in biological molecules.

Answer 20

Hydroxyl (-OH), Carboxyl (-COOH), Amino (-NH₂).

Question 21

What are the four biological macromolecules?

Answer 21

Carbohydrates, lipids, proteins, nucleic acids.

Question 22

What reaction links monomers into polymers?

Answer 22

Dehydration synthesis (condensation reaction).

Question 23

What reaction breaks down polymers?

Answer 23

Hydrolysis.

Question 24

What are nucleic acids made of?

Answer 24

Nucleotides containing a sugar, phosphate, and nitrogenous base.

Question 25

What are the two main types of nucleic acids?

Answer 25

DNA and RNA.

Question 26

Compare DNA and RNA in terms of structure.

Answer 26

DNA: double-stranded, deoxyribose sugar, thymine; RNA: single-stranded, ribose sugar, uracil.

Question 27

What does 'complementary' mean in nucleic acid strands?

Answer 27

Bases pair specifically (A with T/U, G with C) through hydrogen bonds.

Question 28

Given the DNA strand 5’-ATCGG-3’, what is its complementary sequence?

Answer 28

3’-TAGCC-5’.

Question 29

Name two major functions of proteins in living systems.

Answer 29

Catalysis (enzymes), structural support (collagen).

Question 30

What are the basic components of an amino acid?

Answer 30

Amino group (-NH₂), carboxyl group (-COOH), R-group (side chain).

Question 31

How are amino acids linked to form proteins?

Answer 31

By peptide bonds through dehydration synthesis.

Question 32

How does protein structure relate to function?

Answer 32

A protein’s shape determines its ability to interact with other molecules.

Question 33

What are the four levels of protein organization?

Answer 33

Primary, secondary, tertiary, quaternary.

Question 34

What bonds stabilize each level of protein structure?

Answer 34

Primary: peptide bonds; Secondary: hydrogen bonds; Tertiary: hydrogen, ionic, disulfide, hydrophobic interactions; Quaternary: same as tertiary.

Question 35

What happens if a mutation alters a protein’s amino acid sequence?

Answer 35

It may disrupt protein folding and function at multiple structural levels.

Question 36

What are lipids primarily made of?

Answer 36

Carbon, hydrogen, and oxygen, with mostly nonpolar characteristics.

Question 37

How do lipids differ from proteins and nucleic acids?

Answer 37

They are not polymers and are primarily hydrophobic.

Question 38

Describe the structure of a phospholipid.

Answer 38

Hydrophilic head (phosphate group) and two hydrophobic fatty acid tails.

Question 39

What is the role of biological membranes?

Answer 39

They regulate the movement of substances in and out of cells.

Question 40

How do small, nonpolar molecules cross membranes?

Answer 40

By simple diffusion.

Question 41

How do large or charged molecules cross membranes?

Answer 41

Through facilitated diffusion or active transport.

Question 42

Why do phospholipids form bilayers in water?

Answer 42

Hydrophilic heads face water, and hydrophobic tails face inward, avoiding water.

Question 43

Identify the bond type in the fatty acid tails of a phospholipid.

Answer 43

Nonpolar covalent bonds.

Question 44

What determines whether a lipid is solid or liquid at room temperature?

Answer 44

The presence of saturated (solid) or unsaturated (liquid) fatty acids.

Question 45

What are steroids, and why are they important?

Answer 45

Lipids with a four-ring structure; they function as hormones (e.g., cholesterol, testosterone).

Question 46

Predict how an amino acid with a charged R-group will interact with water.

Answer 46

It will be hydrophilic and dissolve in water.

Question 47

Why are enzymes important for biological reactions?

Answer 47

They speed up reactions by lowering activation energy.

Question 48

What happens when a protein denatures?

Answer 48

It loses its shape and function due to environmental changes (e.g., heat, pH).

Question 49

What is an example of a transport protein?

Answer 49

Hemoglobin, which carries oxygen in the blood.

Question 50

What is ATP, and why is it important?

Answer 50

Adenosine triphosphate; it stores and transfers energy for cellular processes.