Honors Biology Final Exam Review: Key Concepts and Topics

How do enzymes regulate metabolism?

Enzymes lower the activation energy for reactions, making them easier and faster, and are necessary to progress from one step to the next.

What are intermediate molecules in metabolic pathways?

Intermediate molecules are substances needed to progress to the next step in a metabolic pathway, such as pyruvic acid in the oxidation process.

Describe the structure and role of a mitochondrion in cellular respiration.

Mitochondria have a folded inner membrane (cristae) that increases surface area for chemical reactions and produce ATP, which is essential for cellular respiration.

How is ATP used as an energy molecule by cells?

ATP releases energy when the last phosphate group is removed, converting it to ADP.

What is oxidation-reduction in cellular respiration?

Oxidation is the removal of electrons, while reduction is the addition of electrons; these processes are always coupled.

What does 'LEO says GER' stand for in oxidation-reduction reactions?

LEO stands for Losing Electrons is Oxidation, and GER stands for Gaining Electrons is Reduction.

What is phosphorylation?

Phosphorylation is the addition of a phosphate group to a molecule.

What is the difference between substrate-level and oxidative phosphorylation?

Substrate-level phosphorylation directly produces ATP, while oxidative phosphorylation uses NADH, FADH, the electron transport chain, and ATP synthase to generate a larger amount of ATP.

What are hydrogen carriers in respiration?

Hydrogen carriers, like NADH and FADH2, accept electrons and transport them in cellular respiration, contributing to ATP production.

What is the ATP equivalency for NADH and FADH2?

NADH yields 3 ATP, while FADH2 yields 2 ATP during the electron transport process.

Write the general equation for aerobic cellular respiration.

C6H12O6 + 6O2 → 6CO2 + 6H2O + energy (ATP).

What occurs during glycolysis?

Glycolysis occurs in the cytosol, is anaerobic, converts glucose into 2 pyruvic acids, produces 4 ATP (2 net), and generates 2 NADH.

What happens during pyruvate oxidation?

Pyruvate oxidation occurs in the mitochondria, is aerobic, produces no ATP directly, and generates NADH while transporting acetyl groups into the Krebs Cycle.

Describe the Krebs Cycle.

The Krebs Cycle occurs in the mitochondrial matrix, is aerobic, oxidizes intermediates, produces 1 ATP per cycle (2 per glucose), and generates NADH and FADH2.

What is the role of coenzyme A in pyruvate oxidation?

Coenzyme A transports the acetyl group into the Krebs Cycle and facilitates the removal of CO2.

What is the difference between lactic acid and alcohol fermentation?

Lactic acid fermentation produces lactic acid and occurs in muscle cells, while alcohol fermentation produces ethanol and occurs in yeast; both processes allow cells to generate energy anaerobically.

Why are fermentation processes used by cells?

Fermentation processes are used by cells to generate energy in the absence of oxygen.

What is produced during the Krebs Cycle per acetyl CoA?

Each acetyl CoA combines with oxaloacetate to produce citric acid, yielding 1 ATP, 3 NADH (6 per glucose), and 1 FADH2 (2 per glucose).

What is the significance of the folded inner mitochondrial membrane?

The folded inner mitochondrial membrane (cristae) increases surface area, allowing more space for chemical reactions and enzyme activity.

How does the removal of electrons relate to cellular respiration?

In cellular respiration, the removal of electrons (oxidation) is coupled with the gaining of electrons (reduction), facilitating energy transfer.

What is the net ATP yield from glycolysis?

The net ATP yield from glycolysis is 2 ATP.

What is the role of lactic acid fermentation in glycolysis?

It keeps glycolysis going by regenerating NAD+ and occurs anaerobically.

What are the products of alcohol fermentation?

Ethanol and carbon dioxide, occurring in yeast.

What is oxidative phosphorylation?

A process in the intermembrane of the mitochondria that is aerobic and involves NADH donating electrons to a protein, which helps pump protons out, creating a gradient.

How does oxygen function in oxidative phosphorylation?

Oxygen accepts electrons and combines them with protons to form water.

What is the function of ATP synthase?

It allows hydrogen ions to flow from high to low concentration, synthesizing ATP in the process.

What are autotrophs?

Organisms that produce their own food.

What are photoautotrophs?

Organisms that produce their own food using photosynthesis.

Which organisms can perform photosynthesis?

Plants, algae, and cyanobacteria.

What is the chemical equation for photosynthesis?

CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂.

What are thylakoids in a chloroplast?

The structures where the majority of light capturing occurs.

What is the stroma in a chloroplast?

The space within the chloroplast.

What are stomata?

Pores that allow gases to enter and exit the plant.

How do guard cells regulate the function of stomata?

Guard cells close the stomata when water levels are low to prevent water loss.

Where do plants acquire light, water, and carbon dioxide?

Light is acquired in the leaves, water in the roots, and carbon dioxide through the stomata in leaves.

What is the difference between light-dependent and light-independent reactions of photosynthesis?

Light-dependent reactions require direct light and occur in the thylakoids, while light-independent reactions do not require direct light but depend on the products of light-dependent reactions and occur in the stroma.

Why are different types of pigment molecules present in photosystems?

To increase the amount of light captured beyond just blue and red wavelengths.

What occurs during noncyclic photophosphorylation?

Light hits photosystem chlorophyll, sending electrons down a chain to form NADPH and pump protons through the membrane, powering ATP synthase.

How are oxygen gas, ATP, and NADPH produced in noncyclic photophosphorylation?

Oxygen is produced by breaking down water, ATP is generated by pumping protons through the membrane, and NADPH is formed as electrons travel down the electron transport chain.

What is the Calvin-Benson cycle?

A light-independent reaction that occurs in the stroma, utilizing ATP and NADPH from light-dependent reactions to fix carbon dioxide and produce sugar.

What is the role of Rubisco in the Calvin-Benson cycle?

Rubisco is an enzyme that catalyzes the fixation of carbon dioxide with RuBP.

How is glucose formed after the Calvin-Benson cycle?

By using ATP and NADPH for reactions that synthesize sugar.

Who is Gregor Mendel and why is he important?

He is known as the father of genetics for his experiments with pea plants that established the foundational principles of heredity.

Who is considered the father of modern genetics?

Gregor Mendel.

What are either/or traits in genetics?

Traits that have two distinct forms, such as purple or white flowers.

What was Mendel's primary goal in his experiments with pea plants?

To determine if plants would pass down specific traits to their offspring.

What was the outcome when Mendel crossbred true-breeding purple and white pea plants?

All offspring were purple, and subsequent self-fertilization resulted in a 3:1 ratio of purple to white flowers.

What is the difference between a gene and an allele?

A gene is a segment of DNA that codes for a trait, while an allele is a variant form of a gene.

What does it mean to be homozygous?

To inherit the same type of allele from both parents.

What does it mean to be heterozygous?

To inherit different alleles from each parent.

What is a genotype?

The combination of alleles an individual has for a particular gene.

What is a phenotype?

The physical expression or outcome of the genotype.

What is Mendel's Law of Segregation?

Each pair of alleles segregates during gamete formation, meaning that alleles from parents separate so that each gamete carries only one allele for each gene.

What is Mendel's Law of Independent Assortment?

Each pair of alleles segregates independently during gamete formation, meaning the segregation of one gene does not affect the segregation of another.

How do genes relate to chromosomes?

Genes are segments of DNA located at specific loci on chromosomes, which independently assort during meiosis.

What is crossing over in genetics?

The process during meiosis where homologous chromosomes exchange segments, allowing for genetic recombination.

What is an example of multiple alleles?

The ABO blood group system, where multiple alleles (IA, IB, i) determine blood type.

What is incomplete dominance?

A genetic situation where neither allele is fully expressed, resulting in a blended phenotype, such as pink flowers from red and white parents.

What is codominance?

A genetic situation where both alleles are fully expressed, such as in AB blood type.

What is polygenic inheritance?

A trait controlled by multiple genes, resulting in a continuous range of phenotypes.

What are sex chromosomes?

Chromosomes that determine an individual's sex, specifically the 23rd pair in humans.

What is the RH factor in genetics?

A specific trait that can show various combinations of alleles, such as A+, B+, A-, B-.

What is the difference between monogenic and polygenic traits?

Monogenic traits are controlled by a single gene, while polygenic traits are influenced by multiple genes.

What is a Punnett Square used for?

To predict the genotypic and phenotypic ratios of offspring from genetic crosses.

What is an example of a trait that is more likely to be inherited by males?

X-linked traits, where males have only one X chromosome.

What is a Y-linked gene?

A gene that is only present on the Y chromosome and is inherited only by males.

What is the difference between smooth and discrete variation?

Smooth variation is linked to polygenic traits and produces continuous variation, while discrete variation is linked to monogenic traits and produces distinct categories.

What is a monogenic trait?

A trait controlled by one gene that tends to produce discrete or discontinuous variation.

What is a polygenic trait?

A trait controlled by multiple genes that produces smooth or continuous variation.

What are monohybrid and dihybrid Punnett squares used for?

They are used to calculate genotypic and phenotypic ratios for traits controlled by one gene (monohybrid) or two genes (dihybrid).

What is epistasis?

Epistasis is the interaction between genes where one gene can mask or alter the expression of another gene.

Give examples of polygenic traits in humans.

Hair color and eye color.

What is catastrophism according to Georges Cuvier?

The theory that massive catastrophes wiped out life on Earth, leading to the creation of new species.

What is uniformitarianism according to Charles Lyell?

The theory that the Earth's features are shaped by slow, gradual processes that are still active today.

What is Lamarckism?

The idea that acquired characteristics can be inherited, suggesting that certain traits are better suited for the environment.

What did Alfred Russel Wallace contribute to evolutionary theory?

He independently proposed the idea of natural selection and collaborated with Darwin to publish their findings.

What was Charles Darwin's role on the HMS Beagle?

He served as the ship's naturalist, documenting the natural world and developing his theories on evolution.

What is natural selection?

A process where organisms with favorable variations are more likely to survive and reproduce, leading to the accumulation of those traits over time.

What is 'descent with modification'?

The concept that modern organisms are descendants of prehistoric ones that have undergone various modifications.

What are homologous structures?

Structures that have the same origin but may serve different functions, providing evidence for divergent evolution.

What are analogous structures?

Structures that have similar functions but do not share a common origin, resulting from convergent evolution.

What are transitional fossils?

Fossils that exhibit characteristics of both an ancestor and its descendant, providing evidence for evolution.

What does comparative embryology provide evidence for?

It shows developmental similarities and differences between embryos of different species, indicating common ancestry.

What does molecular evidence demonstrate?

It shows similarities and differences in DNA and proteins across species, supporting evolutionary relationships.

How do you interpret a cladogram?

The common ancestor is located at the bottom of the cladogram.

What is microevolution?

Microevolution refers to small-scale changes in a population, often at the genetic level.

What is macroevolution?

Macroevolution refers to large-scale evolutionary changes that occur over long periods, leading to the emergence of new species.

How do microevolutionary changes relate to macroevolution?

Microevolutionary changes lead up to macroevolutionary changes.

What are the five mechanisms of microevolution?

1. Mutation: introduces new alleles or changes the frequency of existing ones. 2. No random mating: can lead to more homozygotes and fewer heterozygotes. 3. Migration: introduces new alleles from a source population or removes existing ones. 4. Small population size: chance events have a greater impact on the gene pool, leading to allele frequencies deviating. 5. Natural selection: favors individuals with advantageous traits, increasing those alleles in the next generation.

What is the Bottleneck Effect?

A phenomenon where a population gets smaller, leading to a select group passing on genes, resulting in a smaller gene pool and loss of genetic variation.

What is the Founder Effect?

Occurs when a small group from the original population breaks off to form a new population, leading to traits becoming more prevalent due to the smaller population size.

What is gene flow?

The movement of genes between populations.

What is genetic drift?

Random changes in allele frequencies in populations, differing from natural selection, where traits become more or less common by chance.

What is genetic equilibrium?

A state where allele and genotype frequencies remain constant across generations, indicating the population isn't evolving.

What are the five conditions for a population to be at genetic equilibrium?

1. No mutation. 2. Random mating. 3. No migration. 4. Very large population size. 5. No natural selection.

What is convergent evolution?

Adaptations that evolve independently due to environmental pressures, resulting in analogous structures.

What is divergent evolution?

Occurs when organisms split from a common ancestry, evidenced by homologous structures.

What is coevolution?

The process where the evolution of one species is driven by the evolution of another.

What is sexual selection?

The selection of traits that provide a strong reproductive advantage, which may outweigh survival advantages.

What is sexual dimorphism?

The condition where males and females of a species exhibit different physical characteristics.