Life Science: Biology — Final exam

Question 1 · 1 point

Three independent rates are 4, 6, and 8 units/min. Find the mean.

Question 2 · 1 point

Water's ability to dissolve salts depends on its

1. nonpolar tails
2. polarity and partial charges
3. high density
4. lack of hydrogen bonds

Question 3 · 1 point

Which pairing of macromolecule and monomer is correct?

1. Protein — nucleotide
2. Nucleic acid — amino acid
3. Carbohydrate — monosaccharide
4. Lipid — glucose

Question 4 · 1 point

An enzyme speeds a reaction by

1. raising the temperature
2. lowering the activation energy
3. making a reaction spontaneous
4. being consumed

Question 5 · 1 point

Breaking a chemical bond, considered alone,

1. always releases energy
2. always requires energy
3. never involves energy
4. creates mass

Question 6 · 3 points

An enzyme study varies temperature but also changes enzyme quantity between groups. Explain the confound and redesign using independent replicates.

Question 7 · 3 points

Explain how ATP hydrolysis can support cell work without claiming that breaking a bond alone releases energy.

Question 8 · 1 point

Which statement is NOT one of the three tenets of cell theory?

1. All living things are made of one or more cells
2. The cell is the basic unit of structure and function
3. All cells arise from pre-existing cells
4. All cells contain a nucleus

Question 9 · 1 point

Which statement is part of the cell theory?

1. All cells have a nucleus
2. Cells come only from pre-existing cells
3. All cells are the same size
4. Cells form spontaneously

Question 10 · 1 point

Which crosses the phospholipid bilayer most readily without a transport protein?

1. A sodium ion
2. Glucose
3. Oxygen
4. A protein

Question 11 · 1 point

An animal cell placed in distilled water will

1. shrivel
2. swell and may burst
3. stay the same
4. become turgid safely

Question 12 · 1 point

As a cell grows larger, its surface-area-to-volume ratio

1. increases
2. decreases
3. stays constant
4. doubles

Question 13 · 3 points

For cube-shaped model cells with sides 1 and 3 units, compare surface-area/volume ratios and explain an exchange consequence.

Question 14 · 3 points

A cell enters an equal-pressure solution with higher impermeant solute concentration. Predict initial water flow and distinguish passive from active transport.

Question 15 · 1 point

Which process happens in lung exchange surfaces?

1. Gas moves between air and blood
2. Food is chewed
3. All ATP is made
4. DNA is replicated for every tissue

Question 16 · 1 point

In a negative feedback loop the effector's response

1. amplifies the change
2. opposes the change
3. removes the receptor
4. has no effect

Question 17 · 1 point

Oxygen reaches a muscle cell through the combined action of the

1. digestive and excretory systems
2. respiratory and circulatory systems
3. nervous system alone
4. skeletal system

Question 18 · 1 point

A hormone reaches every tissue but only some respond because responding cells have

1. more blood supply
2. the matching receptor
3. thicker membranes
4. no nucleus

Question 19 · 1 point

A second exposure to the same antigen produces a faster, larger response because of

1. barriers
2. memory lymphocytes
3. fever alone
4. inflammation alone

Question 20 · 3 points

Trace oxygen from air to a muscle cell and explain how exercise illustrates system cooperation.

Question 21 · 3 points

Body temperature rises, triggering sweating. Name the feedback type and explain why a hormone cannot directly trigger its usual response in a cell lacking its receptor.

Question 22 · 1 point

ATP is best described as

1. the organelle where respiration happens
2. the cell's main energy currency
3. the molecule that stores genetic information
4. a green pigment that absorbs light

Question 23 · 1 point

In an ecosystem, energy

1. cycles like matter
2. flows through and is lost as heat
3. is created by producers
4. is destroyed by consumers

Question 24 · 1 point

The oxygen released by photosynthesis comes from

1. carbon dioxide
2. water
3. glucose
4. chlorophyll

Question 25 · 1 point

Oxygen's role in aerobic respiration is to

1. break glucose apart
2. accept electrons at the end of the transport chain
3. produce carbon dioxide directly
4. supply carbon

Question 26 · 1 point

A plant kept in continuous darkness loses mass because it

1. stops respiring
2. respires without photosynthesising
3. loses chloroplasts
4. absorbs no water

Question 27 · 3 points

A plant gains organic carbon while producing oxygen in light. Identify the sources of that carbon and released oxygen, then explain why the plant still respires.

Question 28 · 3 points

A plant's measured net oxygen output is 8 units/hour and respiration consumes 3 units/hour in the supplied model. Find gross oxygen production and state a condition limiting the calculation.

Question 29 · 1 point

In the standard model without new copying errors, what is the main result of mitosis followed by cytokinesis?

1. Two genetically identical daughter cells
2. Four sex cells with half the DNA
3. A cell with double the normal chromosome number
4. A finished protein

Question 30 · 1 point

DNA is replicated during

1. prophase
2. the S phase of interphase
3. anaphase
4. cytokinesis

Question 31 · 1 point

Meiosis I differs from mitosis because in meiosis I

1. chromosomes do not replicate
2. homologous pairs separate
3. no cytokinesis occurs
4. chromosome number doubles

Question 32 · 1 point

A muscle cell and a nerve cell in one person differ mainly in

1. which genes they carry
2. which genes they express
3. their number of chromosomes
4. their DNA sequence

Question 33 · 1 point

During cleavage, cell number rises while total embryo size changes little because

1. cells shrink as cytoplasm is divided
2. new material is added
3. cells fuse
4. mass is lost

Question 34 · 3 points

A species has diploid number 20. Give normal chromosome counts after mitosis, in gametes and after fertilization, and distinguish homologs from sister chromatids.

Question 35 · 3 points

Explain why a neuron and muscle cell can function differently with largely the same genome; distinguish differentiation from division.

Question 36 · 1 point

In DNA, the base adenine (A) always pairs with

1. thymine (T)
2. cytosine (C)
3. guanine (G)
4. another adenine (A)

Question 37 · 1 point

A DNA sample is 22 percent cytosine. The percentage of adenine is

1. 22
2. 28
3. 44
4. 56

Question 38 · 1 point

Deleting a single base from a coding sequence is usually more damaging than substituting one because it

1. removes the gene
2. shifts the reading frame downstream
3. stops replication
4. changes the chromosome number

Question 39 · 1 point

Two parents showing a dominant phenotype have a child with the recessive phenotype. The parents are

1. both homozygous dominant
2. both heterozygous
3. both homozygous recessive
4. one of each homozygote

Question 40 · 1 point

A mother is blood type O and a father type AB. A possible child blood type is

1. O
2. AB
3. A
4. none of these

Question 41 · 3 points

In a hypothetical complete-dominance model, cross Aa with aa. Give genotype and phenotype probabilities and explain why four offspring need not match the ratio.

Question 42 · 3 points

A hormone changes transcription without changing DNA sequence. Explain whether this is a mutation and why a skin-cell mutation is not automatically inherited by offspring.

Question 43 · 1 point

What is the ultimate source of the new heritable variation that natural selection acts upon?

1. An organism's conscious effort to change
2. The environment directly rewriting an organism's genes as needed
3. Mutation (with reshuffling of genes in sexual reproduction)
4. Traits organisms build up through exercise and practice

Question 44 · 1 point

Natural selection acts on

1. variation produced in response to need
2. heritable variation already present
3. acquired characteristics
4. individual effort

Question 45 · 1 point

A bird's wing and an insect's wing are similar in function but differ in structure and ancestry. They are

1. homologous
2. analogous
3. vestigial
4. identical

Question 46 · 1 point

Genetic drift has its largest effect in populations that are

1. very large
2. small
3. growing
4. migrating

Question 47 · 1 point

On a cladogram, two groups are most closely related if they

1. are drawn closest together
2. share the most recent common ancestor
3. are furthest right
4. have the most derived characters

Question 48 · 3 points

A random flood leaves ten survivors regardless of their alleles. Frequencies differ from the original population. Identify a mechanism and compare with selection.

Question 49 · 3 points

A tree groups A and B at a recent node and joins C at an older node. Identify the closest pair and explain why rotating branches does not change the result.

Question 50 · 1 point

All the members of a single species living and interbreeding in the same area make up a

1. community
2. biome
3. trophic level
4. population

Question 51 · 1 point

Competition for food within a population is a

1. density-independent factor
2. density-dependent factor
3. abiotic factor only
4. non-limiting factor

Question 52 · 1 point

Food chains are usually short because at each transfer

1. species run out
2. about ninety percent of the energy is not passed on
3. matter is destroyed
4. predators disappear

Question 53 · 1 point

Decomposers are essential because they

1. add energy to the ecosystem
2. return elements to inorganic forms producers can reuse
3. occupy the first trophic level
4. prevent energy loss

Question 54 · 1 point

Resistance and resilience differ because resilience describes

1. how little a community changes
2. how fully and quickly it recovers
3. its species richness
4. its total biomass

Question 55 · 3 points

A population starts at 500, has 60 births, 40 deaths, 15 immigrants and 25 emigrants. Calculate final size; explain why carrying capacity can change.

Question 56 · 3 points

A conservation survey finds 20 species at site A in 5 h and 12 at B in 1 h. Explain the comparison's limitation, propose a fairer survey and identify an outcome to monitor after an intervention.