Principles of Biology – Fall 2023 – Exam 1 Study Guide

Question 1

What is biology? What is life?

Answer 1

Biology- the study of life

Life is the quality that distinguishes living organisms from dead organisms

Question 2

Explain how biology is considered hierarchical.
What are the various levels of biological
organization?

Answer 2

Atoms: Atoms are the basic units of matter and the smallest particles that make up elements. They consist of a nucleus (protons and neutrons) surrounded by electrons.

Molecules: Molecules are formed when two or more atoms bond together chemically. They can be simple (like water) or complex (like DNA), and they serve as the building blocks of matter.

Organelles: Organelles are specialized structures within cells that perform specific functions. Examples include the nucleus, mitochondria, and chloroplasts.

Cells: Cells are the fundamental units of life and the smallest independently functioning living entities. They can be single-celled organisms or part of multicellular organisms.

Tissues: Tissues are groups of similar cells that work together to perform specific functions. For example, muscle tissue contracts to produce movement.

Organs: Organs are structures made up of different types of tissues that work together to perform specific functions within an organism. The heart is an example of an organ.

Organisms: An organism is a complete, individual living entity capable of carrying out life processes. This can range from a single-celled bacterium to complex multicellular organisms like animals and plants.

Populations: Populations consist of groups of individuals of the same species living in the same geographic area and potentially interbreeding.

Communities: Communities are made up of populations of different species living in the same area and interacting with one another.

Ecosystems: Ecosystems encompass the interactions between all living organisms (biotic factors) and their physical environment (abiotic factors) within a defined area. This includes the exchange of energy and matter.

Biosphere: The biosphere is the highest level of biological organization and represents the sum total of all living organisms on Earth and their interactions with the environment. It includes all ecosystems on the planet

Question 3

List and explain the characteristics of living things

Answer 3

organization
regulation
growth and development energy utilization
response to stimuli
reproduction
evolution

Question 4

Organization: All living things are both_____ and ______

Answer 4

complex and organized

Question 5

List the three Domains.
What are the four kingdoms in Eukarya?

Answer 5

Bacteria: This domain consists of single-celled organisms known as bacteria. They are prokaryotic cells, lacking a nucleus and other membrane-bound organelles

Archaea: Archaea are another group of single-celled prokaryotic organisms. They are known for living in extreme environments such as hot springs, acidic lakes, and deep-sea hydrothermal vents

Eukarya (most complex)(includes all the Animalia (animals) and Plantae (plants) and Fungi (fungi)

Question 6

How does natural selection contribute to evolution?

Answer 6

It is the process by which certain traits or characteristics become more or less common in a population over generations based on how well they enhance an organism’s survival and reproduction in its environment.

Question 7

What is necessary for evolution by natural selection to occur?

Answer 7

Variation: Within a population of organisms, there is genetic variation. Individuals within the population have different traits due to differences in their genes.

Heritability: Some of these traits are heritable, meaning they can be passed from parents to offspring through genes.

Fitness: Some individuals have characteristics that help them survive and reproduce more successfully than other individuals without those characteristics

Adaptation: Over time, the traits that confer advantages in survival and reproduction become more common in the population. This leads to adaptation, where the population becomes better suited to its environment.

Question 8

Are adaptations inherently good or bad? If not, what determines whether a trait is advantageous?

Answer 8

natural selection acts as a filter that favors traits that enhance an organism’s fitness in a given environment. The concept of “advantage” in the context of adaptation is always relative and context-specific. It is not an inherent quality of the trait itself but a reflection of how well the trait helps an organism survive and reproduce in its particular ecological niche

Question 9

What is artificial selection?
How does it differ from natural selection?

Answer 9

Artificial selection, also known as selective breeding, is a process where humans intentionally choose certain traits or characteristics in plants or animals and then breed them to amplify those desired traits over generations.

while natural selection is concerned with traits that affect overall fitness and survival in an organism’s environment, artificial selection is a specific subset of natural selection that focuses exclusively on traits and behaviors related to mating success.

Question 10

List the steps involved in the scientific method.

Answer 10

Observation
Question
Hypothesis
Predictions
Experiment/observation
Conclusion

Question 11

Explain the concept of null hypothesis testing.

What are type I and type II errors?

Answer 11

The null hypothesis (often denoted as “H0”) is a statement or assumption in statistical hypothesis testing that there is no significant difference, effect, or relationship between the variables being studied

A Type I error occurs when you incorrectly reject the null hypothesis when it is actually true. In other words, you conclude that there is a significant effect when there isn’t one.

A Type II error occurs when you fail to reject the null hypothesis when it is actually false. In this case, you conclude that there is no significant effect when there is one.

Question 12

In general, what are the characteristics of a good experiment?

Answer 12

test multiple working hypothesis

repeat experiments

predict specific experimental outcomes

Question 13

What are elements, molecules and compounds?

Answer 13

Elements: Substance that cannot be broken down or converted to another substance by chemical means

Molecules: are formed when two or more atoms chemically bond together. These atoms can be of the same element (O2 for oxygen) or different elements (H2O for water)

Compounds are substances composed of two or more different elements chemically combined in fixed ratios

Question 14

What are the components of an atom? How are they organized?

Answer 14

Proton: positively charge
Neutrons: no charge
electrons: negatively charge

protons and neutrons live in nuclei

electrons outside the nuclei

Question 15

What is an Atomic number and Atomic weight?

Answer 15

atomic number is the protons

Atomic weight: includes the masses of all the protons, neutrons in the atom.

Question 16

What is an isotope?

Answer 16

An isotope is a variant of an element that has the same number of protons (and, therefore, the same atomic number) as other atoms of the same element but a different number of neutrons in its nucleus.

Question 17

Compare and contrast ionic and covalent bonds. Explain how each forms?.

Answer 17

Ionic bonds are bonds that transfer with opposite charged atoms

covalent bonds are bonds that share electrons with uncharged atoms

Atoms can share or transfer electrons to get to 2 or 8 electrons by forming chemical bonds

Question 18

What types of molecules have ionic bonds, covalent bonds, and hydrogen bonds?

Question 19

What is the difference between a polar covalent bond and a nonpolar covalent bond? Give
an example of a molecule that exhibits each.

Answer 19

In a polar covalent bond, electrons are shared between two atoms, but they are not shared equally. One atom has a stronger attraction for the shared electrons, leading to an uneven distribution of electron density.

in a water molecule, oxygen (O) is more electronegative than hydrogen (H). As a result, the electrons in the O-H bonds are pulled closer to oxygen

In a nonpolar covalent bond, electrons are shared equally between two atoms. There is no significant difference in electronegativity between the atoms, resulting in an even distribution of electron density.

In a hydrogen molecule, two hydrogen atoms share electrons equally, as they have the same electronegativity.

Question 20

What are the chemical properties of water and how they contribute to sustain life?

Answer 20

Water is a polar molecule, meaning it has an uneven distribution of electrical charge

Cohesion: water molecules stick to one another

Adhesion: water molecules stick to other polar surfaces

Solvent: a substance, typically a liquid, that has the ability to dissolve other substances

Specific heat: is a measure of how much heat a certain amount of a substance (like a material or substance) needs to absorb to get hotter by a certain amount. In simpler terms, it tells us how easily a substance can heat up when we add heat to it.

thermal expansion: is the tendency of materials to change in size with changes in temperature

Question 21

What does pH measure? How is measured?

Answer 21

below 7 is acidic

above 7 is basic

Neutral is 7

Question 22

What characteristics of Carbon allow it to form the basis of all organic molecules.

Answer 22

Monosaccharide
One sugar molecule – simple
Glucose and fructose
Soluble in water – taste sweet

Disaccharide
Two sugar molecules
Sucrose is made of glucose + fructose
Short term energy storage (mostly plants)

Polysaccharide
Three or more sugar molecules – complex
Long term energy storage

Question 23

List the four major groups of organic molecules. What is their primary function? Know an
example of each.

Answer 23

Carbohydrates
Sugar – energy storage

examples:
Monosaccharides:
glucose, fructose
Disaccharides:
lactose, sucrose
Polysaccharides:
starch, cellulose

Proteins
Enzymes, transporters, receptors

Lactase
an enzyme,
hemoglobin
a transport protein

Nucleic Acids
DNA and RNA – data storage

Example: DNA and RNA

Lipids
Fats – energy, hormones

Example:
Fats triglycerides
Steroids
testosterone
estrogen

Question 24

Dehydration reaction and hydrolysis reaction

Answer 24

Dehydration reaction and hydrolysis reaction are two fundamental types of chemical reactions involving organic molecules

A dehydration reaction is a chemical reaction in which two molecules are joined together to form a larger molecule, and in the process, a water molecule (H2O) is produced as a byproduct.

A hydrolysis reaction is the reverse of a dehydration reaction. It involves the breaking of a covalent bond within a molecule by the addition of a water molecule.

Question 25

Explain the four levels of structure of a protein.

Answer 25

Primary Structure:

The primary structure of a protein is its linear sequence of amino acids linked together by peptide bonds. This sequence is unique for each protein and is determined by the genetic code encoded in DNA.

Amino acids are the building blocks of proteins, and there are 20 different types of amino acids found in proteins, each with a specific side chain (R group).

The secondary structure of a protein refers to the local folding or coiling of the polypeptide chain. It is primarily stabilized by hydrogen bonds between amino acids along the backbone of the chain.

The tertiary structure of a protein is the overall three-dimensional shape or conformation that results from the complex folding of the entire polypeptide chain. It is stabilized by various types of interactions between amino acid side chains (R groups), including hydrogen bonds, disulfide bonds, ionic interactions, and hydrophobic interactions.

Question 26

What molecules are the subunits of nucleic acids?

Answer 26

Nucleotides are the building blocks of nucleic acids, which include DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)

Question 27

Nitrogenous bases

Question 28

What molecules are the subunits of proteins? What are the different levels of protein
structure?

Answer 28

The subunits of proteins are amino acids. There are 20 different types of amino acids, each with a different side chain or R group. The different levels of protein structure are the primary, secondary, tertiary, and quaternary structure.

Question 29

What molecules are the subunits of nucleic acids?

Answer 29

The subunits of nucleic acids are nucleotides.

The three components that make up a nucleic acid are:

Nitrogenous base: Adenine (A), Guanine (G), Cytosine (C), Thymine (T) in DNA or Uracil (U) in RNA.

Sugar: Either deoxyribose in DNA or ribose in RNA.

Phosphate group: A phosphate molecule.

Question 30

What is the difference between a saturated and a nonsaturated fat? Which is liquid at room
temp? Which is solid at room temp?

Answer 30

A saturated fat is a fat molecule in which the carbon chain is fully saturated with hydrogen atoms, meaning there are no double bonds between the carbon atoms. Saturated fats are solid at room temperature.

An unsaturated fat is a fat molecule in which there is at least one double bond between the carbon atoms, resulting in fewer hydrogen atoms. Unsaturated fats tend