Biology 1 - concepts

Question 1

If an aqueous (water-based) solution has a pH of 7, this means that…

Answer 1

This is a solution of pure water. The concentration of H + ions in the water is 10^(-7) M, and the concentration of H+ ions equals the concentration of OH- ions in the water.

Question 2

What is the hydrogen ion [H+] concentration of a solution of pH 8?

Answer 2

10^(-8) M

Question 3

ATP stands for…

Answer 3

Adenosine Triphosphate

Question 4

What charge do electrons carry?

Answer 4

Electrons carry a “-“ (negative) charge.

Question 5

The atomic number of nitrogen is 7. Nitrogen-15 is heavier than nitrogen-14 because the atomic nucleus of nitrogen-15 contains how many neutrons?

Answer 5

8 neutrons

Question 6

Which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH?

A. tomato juice at pH 4
B. black coffee at pH 5
C. gastric juice at pH 2
D. vinegar at pH 3
E. household bleach at pH 12

Answer 6

C. gastric juice at pH 2

Question 7

About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?

Answer 7

Carbon, hydrogen, nitrogen, oxygen

Question 8

What happens when ATP is hydrolyzed?

Answer 8

A phosphate ion is removed to produce ADP+ inorganic Phosphate along with energy that is released and can be harnessed for cells to do work

Question 9

A covalent bond is likely to be polar when…

Answer 9

one of the atoms sharing electrons is much more electronegative than the other atom.

Question 10

A carbon atom is most likely to form what kind of bond(s) with other atoms?

Answer 10

Covalent bonds

Question 11

From precisely where do the energized electrons that are passed through the electron transport chain of photosynthesis originally arise?

Answer 11

A special pair of chlorophyll molecules.

Question 12

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is…

Answer 12

Oxygen

Question 13

Where does the Calvin cycle take place?

Answer 13

Stroma of the chloroplast

Question 14

Approximately how many total ATP molecules are generated by oxidative phosphorylation?

Answer 14

30-34 (net 28-30)

Question 15

The reactions in photosynthesis that produce molecular oxygen (O2) take place in…

Answer 15

The light reactions alone.

Question 16

Some enzymes need non-protein helpers called ________ to facilitate their reactions, and when these coenzymes are organic instead of inorganic substances, they are referred to as ________.

Answer 16

cofactors; coenzymes

Question 17

In addition to ATP, what are the end products of glycolysis?

Answer 17

NADH and pyruvate

Question 18

The first step in the “signal transduction pathway” is referred to as…

Answer 18

Reception

Question 19

Where do the microtubules of the spindle originate during mitosis in both plant and animal cells?

Answer 19

Centrosome

Question 20

Which of the following is characterized by a cell releasing a signal molecule into the environment, followed by a number of cells in the immediate vicinity responding?

Answer 20

Paracrine signaling

Question 21

In eukaryotic cells, chromosomes are composed of…

Answer 21

DNA and proteins

Question 22

Chromosomes duplicate (DNA replicates) in what phase of the cell cycle?

Answer 22

S-phase (as part of interphase)

Question 23

Is cytokinesis part of mitosis?

Answer 23

No, though it partially overlaps with telophase of mitosis.

Cytokinesis and mitosis together is referred to as M-phase.

Question 24

Is this statement true for mitosis, meiosis I, and/or meiosis II?

Independent assortment of chromosomes occurs.

Answer 24

True for meiosis I only.

Question 25

Is this statement true for mitosis, meiosis I, and/or meiosis II? Chromatids are separated from each other.

Answer 25

True for mitosis and meiosis II

Question 26

Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common? I. Alternation of generations II. Meiosis III. Fertilization IV. Gametes V. Spores

Answer 26

II. Meiosis III. Fertilization IV. Gametes

Question 27

During which phase of mitosis do the sister chromatids become daughter chromosomes?

Answer 27

Anaphase

Question 28

Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails?

Answer 28

1/2

Question 29

Consider the scientific method. What step typically comes after a scientist makes an observation about nature or some other aspect of reality?

Answer 29

Forming a question

Question 30

An experiment that tests only one factor at a time by comparing the results between a control group and an experimental group is referred to as…

Answer 30

A controlled experiment

Question 31

What are the properties (defining characteristics) of life?

Answer 31

Cellular Organization Metabolism Homeostasis Growth and Development Reproduction Response to Stimuli Adaptation through Evolution Heredity

Question 32

Summarize Darwin’s concept of natural selection.

Answer 32

The process by which organisms with traits that are better suited to their environment have a higher chance of surviving and reproducing. Over time, these advantageous traits become more common in the population, leading to evolutionary change.

Question 33

What is the smallest particle of any type of matter that retains all the properties of that matter?

Answer 33

Atom

Question 34

When two atoms share electrons, a covalent bond is made. What makes some covalent bonds stronger than other covalent bonds?

Answer 34

The greater the number of electrons shared, the stronger the bond.

Question 35

Why does the structure H−C=C−H fail to make sense chemically?

Answer 35

Carbon has 4 valence electrons, not 3.

Question 36

Does the number of neutrons, the number of protons, or the number of valence electrons most influence the chemical properties/characteristics of a particular atom?

Answer 36

The number of valence electrons.

Question 37

What is the pH scale based on?

Answer 37

The concentration of hydrogen ions in a solution.

Question 38

If a solution contains equal numbers of hydrogen (H+) and hydroxide (OH-) ions, it would be…?

Answer 38

Neutral with a pH of 7

Question 39

Why is the element carbon referred to as the “backbone of life?”

Answer 39

Its versatility allows carbon to form the diverse compounds necessary for life. It is the fundamental building block of organic molecules, such as proteins, lipids, carbohydrates, and nucleic acids.

Question 40

What type of chemical bond is found WITHIN a single water molecule? What type of bond forms BETWEEN adjacent water molecules?

Answer 40

Covalent bonds form individual water molecules. Hydrogen bonds form between different water molecules.

Question 41

Macromolecules such as nucleic acids and proteins are referred to as ___________ because they are built with smaller chemical building blocks known as ____________.

Answer 41

polymers; monomers

Question 42

What are the monomers of nucleic acids called?

Answer 42

Nucleotides

Question 43

The predominant type of lipid that comprises the lipid “bilayer” of cell membranes are...

Answer 43

Phospholipids

Question 44

What are the names of the two types of reactions involving water?

Answer 44

Hydrolysis and condensation (/dehydration synthesis)

Question 45

What chemical characteristic/property defines all lipids?

Answer 45

All lipids are hydrophobic.

Question 46

Why have proteins been dubbed the “workhorses of life”?

Answer 46

They perform a wide variety of essential functions in cells, including acting as enzymes (catalysts), supporting structure, transporting molecules, and regulating processes.

Question 47

What is the characteristic/aspect of DNA that makes it unique and able to function as the hereditary material for living organisms?

Answer 47

It provides instruction for its own replication.

Question 48

What is wrong with the following statement? “Prokaryotic cells have a smaller nucleus than do typical eukaryotic cells.”

Answer 48

Prokaryotic cells have no true membrane-bound nucleus.

Question 49

Which organelles of the cell are believed to have undergone endosymbiosis as part of their evolutionary origin as organelles?

Answer 49

Mitochondria and chloroplasts

Question 50

Which organelles are found in both prokaryotic and eukaryotic cells?

Answer 50

Cell membrane, cytoplasm, ribosomes

Question 51

What organelles make up the endomembrane system?

Answer 51

Nuclear envelope, endoplasmic reticulum (ER), golgi apparatus, lysosomes, vacuoles, and vesicles.

Question 52

What is it about plant cells that allows them to thrive in a hypotonic environment that would otherwise cause animal cells to lyse and die?

Answer 52

They have a cell wall.

Question 53

What is the “fluid” and what is the “mosaic” in the fluid mosaic model?

Answer 53

The "fluid" refers to the lipid bilayer. The "mosaic" refers to the variety of proteins embedded within the lipid bilayer.

Question 54

What role does cholesterol play in the properties of the plasma membrane?

Answer 54

Cholesterol helps in maintaining the fluidity and stability of the plasma membrane. It stabilizes fluidity and enhances membrane integrity.

Question 55

What are the functions that proteins play with regard to the cell membrane?

Answer 55

Transport, receptors, anchorage, enzymatic activity, cell-cell recognition, and intercellular joining.

Question 56

How does energy move through ecosystems? Where and how does it enter and how is it used and/or dissipated?

Answer 56

Energy enters ecosystems as sunlight, is converted and passed through the food chain, used by organisms, and eventually dissipated as heat.

Question 57

Which series of energetic pathways, fermentation or cellular respiration, is more efficient in maximizing the net production of ATP per glucose molecule consumed?

Answer 57

Cellular respiration is more efficient than fermentation. Fermentation is moreso used for when there is no oxygen available.

Question 58

From where do the energized electrons that are passed through the electron transport chain of photosynthesis originally arise?

Answer 58

Pigment molecules within the photosystem (like chlorophyll).

Question 59

The enzyme that uses energy from the diffusion of H+ (protons) moving down their concentration gradient to “recharge” ADP into ATP is called…

Answer 59

ATP Synthase

Question 60

In photosynthesis, what is the name of the reaction that actually builds the 3-Carbon subunits (G3P) that are turned into sugars?

Answer 60

The Calvin cycle

Question 61

Why are photosynthetic parts of the plant green in color?

Answer 61

Photosynthetic parts of the plant appear green because of the pigment chlorophyll, which absorbs light most efficiently in the blue and red wavelengths but reflects and transmits green light.

Question 62

What is considered the “second messenger” in the activity pathway of water soluble hormones?

Answer 62

cAMP

Question 63

What are the ways that cells communicate?

Answer 63

Direct contact (gap junctions, cell-cell recognition) Chemical signaling (autocrine signaling, paracrine signaling, endocrine signaling, synaptic signaling) Signal transduction

Question 64

Name and describe each of the 3 stages of cell signaling.

Answer 64

Reception: A signaling molecule binds to a receptor on the cell surface or inside the cell. Transduction: The signal is relayed through a series of intracellular molecules. Response: The cell responds with changes in behavior, gene expression, or activity.

Question 65

Did binary fission most likely arise before or after the process of mitosis?

Answer 65

Binary fission most likely arose before mitosis. It is a simpler form of cell division. Mitosis likely evolved later in eukaryotic cells, which have more intricate structures and multiple chromosomes that require a more organized division process.

Question 66

What type of cell does meiosis make?

Answer 66

Gametes (sperm or ova)

Question 67

In humans, how many chromosomes do the daughter cells produced by the end of meiosis have?

Answer 67

23 (single stranded) chromosomes

Question 68

When during meiosis does “crossing over” take place?

Answer 68

Prophase I

Question 69

What is the difference between homologous chromosomes and sister chromatids?

Answer 69

Homologous chromosomes are a pair of chromosomes, that have the same genes but may have different versions (alleles) of those genes. Sister chromatids are identical copies of a chromosome, formed by DNA replication.

Question 70

The specific location of a gene on a chromosome is referred to as a...

Answer 70

Locus

Question 71

From a molecular standpoint, what exactly is an allele?

Answer 71

An allele is a variant form of a gene. Per gene, an individual typically carries two alleles — one inherited from each parent. These alleles may be the same (homozygous) or different (heterozygous).

Question 72

What is different about the Y vs X chromosomes?

Answer 72

The X chromosome is larger and contains many genes that the Y chromosome does not. The X and Y chromosomes pair during meiosis, but only share a small region of homology.

Question 73

What does semiconservative DNA replication mean?

Answer 73

After DNA replication, each new DNA molecule consists of one original (parental) strand and one newly synthesized strand.

Question 74

Before DNA can be replicated, it must be uncoiled and the two strands separated. The enzyme that performs this function is called...

Answer 74

Helicase

Question 75

Chargaff's Rules state that in a given DNA molecule...

Answer 75

The amount of adenine (A) equals the amount of thymine (T) (A = T) and the amount of cytosine (C) equals the amount of guanine (G) (C = G).