Biology Test Practice Test: Video 3 Answers (25 Questions) — Questions and Answers

Question 1: What is the main function of the waxy cuticle on leaf surfaces?

Facilitate nutrient uptake
Absorb CO2 from the atmosphere
Prevent excessive water loss (Correct answer)
Reflect harmful UV radiation

Correct answer: Prevent excessive water loss

The cuticle is a layer of cutin secreted by epidermal cells that reduces transpiration by limiting water vapor loss from leaf surfaces.

Question 2: What type of root adaptation allows mangrove trees to exchange gases in waterlogged soils?

Pneumatophores (Correct answer)
Haustoria
Contractile roots
Prop roots

Correct answer: Pneumatophores

Pneumatophores are specialized vertical roots that extend above the waterline to allow gas exchange in oxygen-poor, flooded soils.

Question 3: What is alternation of generations in plants?

A life cycle alternating between haploid and diploid stages (Correct answer)
The seasonal change in leaf color
Annual vs perennial growth patterns
The cycle of pollination and seed dispersal

Correct answer: A life cycle alternating between haploid and diploid stages

Alternation of generations is a reproductive cycle where plants alternate between a multicellular haploid stage (gametophyte) and a multicellular diploid stage (sporophyte).

Question 4: What is the role of stomata in plants?

Reproduction
Structural support
Nutrient absorption from soil
Gas exchange and water vapor release (Correct answer)

Correct answer: Gas exchange and water vapor release

Stomata are tiny pores on leaf surfaces that allow carbon dioxide in for photosynthesis and release oxygen and water vapor through transpiration.

Question 5: Which tissue in plants is responsible for transporting water from roots to leaves?

Parenchyma
Phloem
Xylem (Correct answer)
Epidermis

Correct answer: Xylem

Xylem tissue transports water and dissolved minerals from the roots upward through the plant using a combination of root pressure, capillary action, and transpiration pull.

Question 6: What does the Hardy-Weinberg principle predict about allele frequencies in a population?

They increase over time due to selection
They remain constant in the absence of evolutionary forces (Correct answer)
They decrease due to genetic drift
They fluctuate randomly each generation

Correct answer: They remain constant in the absence of evolutionary forces

The Hardy-Weinberg principle states allele and genotype frequencies remain constant across generations in a non-evolving population.

Question 7: Which stage of meiosis results in genetic recombination via crossing over?

Anaphase II
Metaphase I
Telophase II
Prophase I (Correct answer)

Correct answer: Prophase I

Crossing over between homologous chromosomes occurs during Prophase I of meiosis, generating new allele combinations.

Question 8: What is the purpose of a Punnett square?

To measure genetic drift.
To map chromosomes.
To predict genetic trait probabilities (Correct answer)
To display evolutionary relationships.

Correct answer: To predict genetic trait probabilities

A Punnett square is a diagrammatic tool used in genetics to predict the probability of offspring inheriting specific genotypes and phenotypes from their parents. By illustrating all possible combinations of alleles from each parent, it helps visualize and calculate the likelihood of different genetic outcomes. This makes it essential for understanding Mendelian inheritance patterns.

Question 9: Natural selection acting on quantitative traits toward an intermediate phenotype is called:

Sexual selection
Disruptive selection
Directional selection
Stabilizing selection (Correct answer)

Correct answer: Stabilizing selection

Stabilizing selection favors intermediate phenotypes and reduces variation in a population over time.

Question 10: What is natural selection?

Artificial breeding by humans.
The process where advantageous traits become more common (Correct answer)
Sudden environmental changes.
Random changes in DNA.

Correct answer: The process where advantageous traits become more common

Natural selection is a key mechanism of evolution, described by Charles Darwin. It describes how organisms better adapted to their environment tend to survive and produce more offspring. Over generations, individuals with advantageous heritable traits are more likely to reproduce, leading to these traits becoming more prevalent in the population, thus driving evolutionary change.

Question 11: Beta-oxidation is the metabolic process that breaks down:

Carbohydrates
Fatty acids (Correct answer)
Proteins
Nucleic acids

Correct answer: Fatty acids

Beta-oxidation sequentially cleaves two-carbon units from fatty acid chains, generating acetyl-CoA for the Krebs cycle.

Question 12: The Krebs cycle occurs in which part of the mitochondria?

Inner membrane
Outer membrane
Intermembrane space
Matrix (Correct answer)

Correct answer: Matrix

The Krebs (citric acid) cycle takes place in the mitochondrial matrix where its enzymes are dissolved.

Question 13: Phospholipids are amphipathic molecules, meaning they have:

Two phosphate groups
Both hydrophilic and hydrophobic regions (Correct answer)
Only nonpolar tails
Positive and negative charges on the same tail

Correct answer: Both hydrophilic and hydrophobic regions

Phospholipids have a polar phosphate head (hydrophilic) and two nonpolar fatty acid tails (hydrophobic), driving bilayer formation.

Question 14: Which coenzyme carries electrons from the Krebs cycle to the electron transport chain?

NAD+ (Correct answer)
FAD
CoA
ATP

Correct answer: NAD+

NAD+ is reduced to NADH in the Krebs cycle, then donates its electrons to Complex I of the electron transport chain.

Question 15: During fermentation in human muscle cells, pyruvate is converted to:

Ethanol
Citrate
Acetyl-CoA
Lactate (Correct answer)

Correct answer: Lactate

In anaerobic conditions, human muscle cells convert pyruvate to lactate via lactic acid fermentation to regenerate NAD+.

Question 16: What is the function of the cell membrane?

It stores genetic information.
It controls what enters and leaves the cell (Correct answer)
It synthesizes proteins.
It produces energy for the cell.

Correct answer: It controls what enters and leaves the cell

The cell membrane, composed of a lipid bilayer, acts as a selective barrier that encloses the cell's contents. Its primary function is to regulate the passage of substances, such as nutrients and waste products, into and out of the cell. This selective permeability is vital for maintaining the cell's internal environment and protecting it from external changes, ensuring proper cellular function and survival.

Question 17: What is the main function of the endoplasmic reticulum (ER)?

Housing genetic material.
Producing ATP.
Synthesizing proteins and lipids (Correct answer)
Breaking down toxins.

Correct answer: Synthesizing proteins and lipids

The endoplasmic reticulum (ER) is a vast network of membranes within the cytoplasm. The rough ER, studded with ribosomes, is primarily involved in synthesizing and folding proteins destined for secretion or insertion into membranes. The smooth ER, lacking ribosomes, is crucial for lipid synthesis, detoxification of drugs and poisons, and calcium storage, making the ER vital for diverse cellular functions.

Question 18: What is the function of the Golgi apparatus?

Producing ribosomes.
Breaking down macromolecules.
Generating ATP.
Modifying and packaging proteins and lipids (Correct answer)

Correct answer: Modifying and packaging proteins and lipids

The Golgi apparatus, or Golgi complex, acts like a cellular post office. Its main function is to further process, sort, and package proteins and lipids that have been synthesized in the endoplasmic reticulum. These modified molecules are then directed to their correct destinations, either within the cell or for secretion outside the cell, ensuring proper cellular organization and function.

Question 19: What is the function of ribosomes?

Protein synthesis (Correct answer)
Energy storage.
Transporting materials.
Waste removal.

Correct answer: Protein synthesis

Ribosomes are essential cellular organelles responsible for translating messenger RNA (mRNA) into proteins. They read the genetic code carried by mRNA and assemble amino acids in the correct sequence to form functional proteins. These proteins are crucial for virtually all cellular processes, structures, and enzymatic reactions, making protein synthesis a fundamental activity for life.

Question 20: What is the role of lysosomes?

Digesting waste and cellular debris (Correct answer)
Storing nutrients.
Maintaining cell shape.
Transporting proteins.

Correct answer: Digesting waste and cellular debris

Lysosomes are membrane-bound organelles containing powerful digestive enzymes. Their primary role is to break down waste materials, cellular debris, foreign invaders like bacteria, and worn-out organelles. This process, called autophagy, is crucial for recycling cellular components, maintaining cell health, and protecting the cell from harmful substances.

Question 21: The exchange of gases between the blood and body tissues is called:

Pulmonary respiration
Ventilation
External respiration
Internal respiration (Correct answer)

Correct answer: Internal respiration

Internal (tissue) respiration is the exchange of O₂ and CO₂ between systemic capillary blood and surrounding tissue cells.

Question 22: During an action potential, the rapid influx of which ion causes depolarization of the neuron?

Sodium (Na⁺) (Correct answer)
Calcium (Ca²⁺)
Potassium (K⁺)
Chloride (Cl⁻)

Correct answer: Sodium (Na⁺)

Voltage-gated Na⁺ channels open during depolarization, allowing rapid influx of sodium ions and driving the membrane potential toward +30 mV.

Question 23: In the digestive system, which enzyme begins the chemical digestion of starch in the mouth?

Pepsin
Lipase
Salivary amylase (Correct answer)
Trypsin

Correct answer: Salivary amylase

Salivary amylase (ptyalin) is secreted by salivary glands and hydrolyzes starch into maltose and shorter polysaccharides.

Question 24: Which lobe of the cerebral cortex contains the primary visual cortex?

Frontal lobe
Occipital lobe (Correct answer)
Temporal lobe
Parietal lobe

Correct answer: Occipital lobe

The primary visual cortex (V1) is located in the occipital lobe, specifically in the banks of the calcarine sulcus.

Question 25: The process by which phagocytes engulf and destroy pathogens is called:

Phagocytosis (Correct answer)
Exocytosis
Pinocytosis
Apoptosis

Correct answer: Phagocytosis

Phagocytosis is receptor-mediated endocytosis where cells such as neutrophils and macrophages engulf large particles including bacteria.

Biology Test Practice Test: Video 3 Answers (25 Questions)

What is the main function of the waxy cuticle on leaf surfaces?

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