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

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

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.

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

Answer: Pneumatophores

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

What is alternation of generations in plants?

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).

What is the role of stomata in plants?

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.

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

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.

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

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.

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

Answer: Prophase I

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

What is the purpose of a Punnett square?

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.

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

Answer: Stabilizing selection

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

What is natural selection?

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.

Beta-oxidation is the metabolic process that breaks down:

Answer: Fatty acids

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

The Krebs cycle occurs in which part of the mitochondria?

Answer: Matrix

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

Phospholipids are amphipathic molecules, meaning they have:

Answer: Both hydrophilic and hydrophobic regions

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

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

Answer: NAD+

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

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

Answer: Lactate

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

What is the function of the cell membrane?

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.

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

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.

What is the function of the Golgi apparatus?

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.

What is the function of ribosomes?

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.

What is the role of lysosomes?

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.