Enzyme Function and Activity Quiz

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Questions and Answers

What type of cells undergo meiosis?

Somatic cells

Tumor cells

Gametes (correct)

Sister chromatids

What is the primary purpose of cell cycle checkpoints?

To promote rapid cell division

To regulate the chromatin structure

To monitor the DNA for mutations (correct)

To ensure the cell divides into four cells

Which of the following best describes crossing over in meiosis?

The separation of sister chromatids

The doubling of the genetic material

The exchange of genetic material between homologous chromosomes (correct)

The random assortment of chromosomes

How many cells and what type of cells result from mitosis?

Two diploid cells Signup and view all the answers

What does it mean for a person to have trisomy 21?

They have an extra copy of chromosome 21 Signup and view all the answers

What is the role of NAD+ in redox reactions?

It serves as an electron acceptor. Signup and view all the answers

How much net ATP is generated from glycolysis?

2 ATP Signup and view all the answers

What type of fermentation occurs in human muscle cells?

Lactic acid fermentation Signup and view all the answers

What characteristic differentiates cellular respiration from fermentation?

Respiration produces more ATP. Signup and view all the answers

What occurs during decarboxylation in cellular respiration?

Carbon dioxide is removed from a molecule. Signup and view all the answers

Which cellular organelle is primarily responsible for photosynthesis?

Chloroplasts Signup and view all the answers

Which statement about the end products of fermentation is true?

They retain high-energy potential within their bonds. Signup and view all the answers

Where does the Calvin cycle occur within plant cells?

In the chloroplast stroma Signup and view all the answers

What is the primary chemical reaction catalyzed by lactase?

Hydrolysis of lactose Signup and view all the answers

What is denaturation in relation to enzymes?

A permanent change in enzyme shape that affects function Signup and view all the answers

Under which light intensity conditions is dissolved oxygen most abundant during photosynthesis?

High light intensity Signup and view all the answers

Which statement describes the significance of the Great Oxygenation Event?

It caused a dramatic increase in atmospheric oxygen Signup and view all the answers

Which of the following describes the difference between catabolism and anabolism?

Catabolism involves breakdown of molecules, while anabolism builds them up Signup and view all the answers

What is the first law of thermodynamics commonly known as?

Energy can only be transformed, not created or destroyed Signup and view all the answers

What role do R groups play in enzyme functionality?

They determine the substrate specificity of the enzyme Signup and view all the answers

How is energy released from ATP during cellular processes?

By breaking the bond between the second and third phosphate groups Signup and view all the answers

Study Notes

Enzyme Function

Enzymes speed up chemical reactions without being consumed in the process.
They act as catalysts, lowering the activation energy required for a reaction to start.
Lactase, a specific enzyme, breaks down lactose, a sugar found in milk.
Lactose intolerance arises from the body's inability to produce sufficient lactase, leading to digestive discomfort after consuming dairy.
Approximately 65% of the global population is lactose intolerant.
Lactose tolerance is a relatively recent adaptation, evolving when humans began consuming dairy products.

Enzyme Activity

Enzymes have optimal conditions for activity, influenced by factors like pH and temperature.
Each enzyme has an optimal pH and temperature where it functions most efficiently.
The enzyme lactase exhibits peak activity at a pH around 6.0 and a temperature of about 37°C.
Denaturation occurs when the enzyme's structure is disrupted by extreme temperatures or pH changes, causing it to lose its function.
High heat, above the optimal temperature, can lead to denaturation, causing the enzyme to unfold and lose its shape, rendering it ineffective.

Photosynthesis

Photosynthesis is the process plants use to convert light energy into chemical energy, mainly in the form of glucose.
Light intensity directly influences the rate of photosynthesis.
Higher light intensity results in increased dissolved oxygen production, indicating higher rates of photosynthesis.
The Great Oxygenation Event (GOE) refers to the significant increase in atmospheric oxygen levels about 2.4 billion years ago.
This event was crucial for the evolution of aerobic life on Earth.
Cyanobacteria, a type of photosynthetic bacteria, were primarily responsible for the GOE.

Cellular Respiration

Cellular respiration is the process of breaking down glucose to release energy in the form of ATP.
Anabolism involves building up complex molecules from simpler ones, while catabolism breaks down complex molecules into simpler ones.
The first law of thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another.
Potential energy is stored energy within the bonds of molecules, while kinetic energy is the energy of motion.
Enzymes play a crucial role in cellular respiration by catalyzing specific reactions.
Each enzyme possesses a unique active site that binds to a specific substrate molecule.
Substrate is the molecule that the enzyme acts upon.
Product is the molecule resulting from the enzyme-catalyzed reaction.
Phosphorylation involves the addition of a phosphate group to a molecule, often to activate it.
ATP is the primary energy currency of cells.
Energy is released from ATP when a phosphate group is removed, breaking the bond and producing ADP and a free phosphate group.

Cellular Respiration Pathways

Cellular respiration occurs in three main stages: glycolysis, the citric acid cycle (Krebs cycle), and the electron transport chain.
Glycolysis occurs in the cytoplasm and breaks down glucose into pyruvate, producing a net of 2 ATP molecules.
The citric acid cycle takes place in the mitochondria and completes the oxidation of pyruvate, producing electron carriers (NADH and FADH2) and generating ATP.
Electron transport chain involves a series of electron carriers within the mitochondria, using the energy from NADH and FADH2 to pump protons across the inner mitochondrial membrane, ultimately generating a large amount of ATP (approximately 34 ATP).
Oxidation is the loss of electrons, while reduction is the gain of electrons.
NAD+ and NADH are electron carriers involved in redox reactions.
NAD+ is an electron acceptor, while NADH is an electron donor.

Comparing Respiration and Fermentation

Aerobic respiration requires oxygen and produces significantly more ATP than fermentation.
Fermentation occurs in the absence of oxygen and produces much less ATP.
Two types of fermentation: lactic acid fermentation and alcoholic fermentation.
The availability of oxygen determines which pathway is used by an organism.
When oxygen is present, aerobic respiration is preferred due to its higher ATP yield.
Fermentation allows cells to generate some ATP even without oxygen.
Fermentation end products, such as lactic acid, are not further oxidized due to the lack of oxygen.

Photosynthesis Stages

Photosynthesis occurs in two main stages: light-dependent reactions and the Calvin cycle.
Light-dependent reactions occur in the thylakoid membranes of chloroplasts, capturing light energy to produce ATP and NADPH.
The Calvin cycle takes place in the stroma of chloroplasts, utilizing ATP and NADPH from the light-dependent reactions to fix carbon dioxide into glucose.
Carbon fixation is the process of incorporating carbon dioxide into organic molecules.
Glyceraldehyde-3-phosphate (G3P) is the molecule produced from the Calvin cycle and can be converted into glucose.
Autotrophs are organisms that produce their own food through photosynthesis.
Heterotrophs are organisms that obtain energy by consuming other organisms.
Photosynthetic organisms occupy the producer trophic level in food chains.

Chromosomes and DNA Packaging

Genome refers to the complete set of genetic information in an organism.
Homologous pairs are matching chromosomes from each parent.
Diploid cells have two sets of chromosomes (2n).
Haploid cells have one set of chromosomes (n).
Karyotype is a visual representation of an individual's chromosomes.
Alleles are alternative forms of a gene.
Somatic cells are non-reproductive cells, diploid in most organisms.
Gametes are reproductive cells (sperm and egg), haploid in most organisms.
Sex chromosomes (X and Y) determine biological sex.
Autosomes are non-sex chromosomes.
Zygote is a fertilized egg, formed by the fusion of a sperm and an egg.
Histones are proteins that help package and organize DNA into chromosomes.
Sister chromatids are identical copies of a chromosome joined at the centromere.

Cell Cycle

The cell cycle consists of two main phases: interphase and the mitotic phase.
Interphase is the longest phase, during which the cell grows and replicates its DNA.
Mitosis is the division of the nucleus, resulting in two daughter cells with identical genetic material.
Stages of mitosis: prophase, metaphase, anaphase, telophase, followed by cytokinesis.

Cell Cycle Checkpoints

Cell cycle checkpoints are crucial for ensuring accurate DNA replication and proper cell division.
Mutations in tumor suppressor genes can inactivate these checkpoints, contributing to uncontrolled cell growth and cancer development.

Sexual Reproduction

Sexual reproduction involves the fusion of two gametes, providing genetic diversity in offspring.

Meiosis

Meiosis is a type of cell division that produces four haploid daughter cells from a diploid parent cell.
Crossing over is the exchange of genetic material between homologous chromosomes during prophase I of meiosis I.
Meiosis consists of two rounds of division: Meiosis I and Meiosis II.
Meiosis I is the first division, separating homologous chromosome pairs.
Meiosis II resembles mitosis, separating sister chromatids.

Comparing Mitosis and Meiosis

Mitosis produces two identical diploid daughter cells.
Meiosis produces four unique haploid daughter cells.

Genetic Diversity

Genetic diversity in gametes arises from two key processes:
- Crossing over during meiosis I, which shuffles genetic material between homologous chromosomes.
- Independent assortment of chromosomes during meiosis I, which randomly aligns homologous pairs of chromosomes at the metaphase plate, leading to different combinations of chromosomes in daughter cells.

Errors in Chromosome Number

Karyotype is a display of an individual's chromosomes arranged in order of size.
Autosomes are non-sex chromosomes, numbered 1-22.
Nondisjunction is the failure of chromosomes to separate properly during cell division, resulting in an abnormal number of chromosomes in daughter cells.
Euploid refers to a normal number of chromosomes.
Aneuploid refers to an abnormal number of chromosomes.
Monosomy refers to the absence of a chromosome (one copy instead of two).
Trisomy refers to the presence of an extra chromosome (three copies instead of two).
Trisomy 21 is a condition where an individual has three copies of chromosome 21, also known as Down syndrome.

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Description

Test your knowledge on enzymes, their functions, and how they catalyze chemical reactions. This quiz covers important concepts like lactase, lactose intolerance, and the optimal conditions for enzyme activity. Explore how enzymes are affected by pH, temperature, and other factors that can lead to denaturation.