Biology Chapter on DNA and Cell Division

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Questions and Answers

What is the structure of DNA?

Triple helix with ribose sugar

Circular structure with uracil

Double helix with sugar and phosphate backbone (correct)

Single strand with ribose sugar

Which statement accurately describes exons and introns?

Exons are non-coding regions; introns are coding regions.

Exons and introns have equal functions in protein synthesis.

Both exons and introns code for proteins.

Exons are coding regions; introns are non-coding regions. (correct)

What role does RNA polymerase play in protein synthesis?

It translates codons into proteins.

It unzips DNA and creates mRNA. (correct)

It binds amino acids to form proteins.

It seals the new DNA strands.

What type of mutation leads to a shorter protein by changing an amino acid codon to a stop codon?

Nonsense mutation Signup and view all the answers

What is the primary purpose of DNA replication?

To prepare for cell division. Signup and view all the answers

Which enzyme is responsible for sealing the new DNA strands during replication?

DNA ligase Signup and view all the answers

What influences gene expression according to the regulation of protein production?

Hormones, drugs, diet, and lifestyle Signup and view all the answers

Which type of mutation is considered the worst as it alters the entire protein sequence?

Frameshift mutation Signup and view all the answers

What is the primary purpose of mitosis in cells?

Growth, repair, and maintenance of tissues Signup and view all the answers

How many chromosomes are present in a typical diploid human cell?

46 Signup and view all the answers

What is a characteristic feature of meiosis compared to mitosis?

Results in four non-identical cells Signup and view all the answers

What type of chromosomal aberration involves a failure in chromosome separation during cell division?

Non-disjunction Signup and view all the answers

What defines polyploidy in cells?

Extra sets of chromosomes beyond two Signup and view all the answers

Females typically have which sex chromosome configuration?

XX Signup and view all the answers

Which condition is characterized by an extra copy of chromosome 21?

Down Syndrome Signup and view all the answers

What is the chromosome number in haploid cells?

23 Signup and view all the answers

What impact do chromosomal aberrations typically have on cells?

They can lead to developmental and health issues Signup and view all the answers

Which of the following best describes the process of crossing over in meiosis?

Exchange of genetic material between homologous chromosomes Signup and view all the answers

What is one of the main purposes of meiosis?

Ensuring genetic diversity in offspring Signup and view all the answers

Which syndrome is associated with females having only one X chromosome?

Turner Syndrome Signup and view all the answers

Which stage of meiosis involves the pairing of chromosomes to form tetrads?

Meiosis I Signup and view all the answers

What type of chromosomal abnormality results in an abnormal number of chromosomes that is not a multiple of the normal set?

Aneuploidy Signup and view all the answers

What genetic condition is caused by a deletion on chromosome 5?

Cri-du-chat Syndrome Signup and view all the answers

In what type of chromosomal aberration does a section of a chromosome get copied, resulting in extra genetic material?

Duplication Signup and view all the answers

What is the primary impact of an inversion in a chromosome?

It does not affect gene function unless crucial genes are disrupted. Signup and view all the answers

Which genotype combination represents a carrier of a recessive trait?

Ff Signup and view all the answers

What is an example of incomplete dominance in genetics?

Pink flowers from crossing red and white flowers Signup and view all the answers

Which type of chromosomal change involves the exchange of segments between non-homologous chromosomes?

Reciprocal Translocation Signup and view all the answers

Which condition is characterized by a blend of both alleles in its phenotype?

Incomplete dominance Signup and view all the answers

What is defined as the observable traits of an individual, influenced by both genotype and environment?

Phenotype Signup and view all the answers

What term refers to variants of a gene that are common in a population?

Polymorphisms Signup and view all the answers

A person with genotype BB for a trait will display which of the following phenotypes?

Brown eyes Signup and view all the answers

Which of the following statements about dominant and recessive alleles is true?

An individual needs only one dominant allele to express the trait. Signup and view all the answers

Which chromosomal abnormality can lead to chronic myeloid leukemia due to the exchange of chromosomes?

Reciprocal Translocation Signup and view all the answers

What is a characteristic of RNA methylation in the context of epigenetics?

It affects gene expression without changing the DNA. Signup and view all the answers

Which statement best explains the influence of diet on epigenetic modifications?

Diet can lead to reversible changes in gene expression. Signup and view all the answers

Which of the following is NOT considered an epigenetic mechanism?

Protease modification Signup and view all the answers

What is one potential outcome of epigenetic modification?

Development of diseases such as cancer. Signup and view all the answers

When do epigenetic modifications typically occur?

Throughout an individual's lifetime. Signup and view all the answers

What is the primary purpose of prevalence in epidemiology?

To indicate how widespread a condition is Signup and view all the answers

What distinguishes monozygotic twins from dizygotic twins?

Monozygotic twins share 100% of their genetics Signup and view all the answers

What is the main goal of adoption studies?

To analyze environmental influences on adopted individuals Signup and view all the answers

What characterizes polygenic traits?

Influenced by multiple genes Signup and view all the answers

Which of the following is considered an environmental disease?

Influenza Signup and view all the answers

How does epigenetics contribute to our understanding of traits?

It reveals how environmental factors influence gene expression Signup and view all the answers

Which skin layer is primarily responsible for protection from environmental threats?

Stratum Corneum Signup and view all the answers

Which of the following cells in the skin is specialized for detecting mechanical stress?

Merkel Cells Signup and view all the answers

What is the primary function of the dermis layer of the skin?

Providing sensation and support Signup and view all the answers

How long does it typically take for a skin cell to move from the stratum basale to the surface?

30 days Signup and view all the answers

What is the role of melanocytes in the skin?

Absorbing UV radiation Signup and view all the answers

Which of the following best describes complex diseases?

Involve both genetic and environmental factors Signup and view all the answers

Which skin layer acts as a cushioning and lubrication interface between skin and underlying muscle tissue?

Hypodermis Signup and view all the answers

Which statement about skin cell types is correct?

Merkel cells detect mechanical stimuli. Signup and view all the answers

What is the primary function of the sebaceous gland?

Produces sebum to prevent dehydration and dryness. Signup and view all the answers

Which type of sweat gland is primarily responsible for thermal regulation?

Eccrine sweat glands Signup and view all the answers

What characterizes the third degree of frostbite?

It includes necrosis and deep tissue damage. Signup and view all the answers

What is a common cause of hirsutism in females?

Endocrine disorders such as PCOS. Signup and view all the answers

What is a common symptom of Onychomycosis?

Yellowing and elevation of the nail. Signup and view all the answers

Which layer of skin does Stage 2 pressure injury affect?

The epidermis and dermis. Signup and view all the answers

What is the effect of UV exposure on skin aging?

Damages blood vessels and contributes to wrinkles. Signup and view all the answers

Which factor is NOT typically associated with skin aging?

Increased fibroblast activity. Signup and view all the answers

What is the significant danger of rapid warming of frostbitten areas?

Reperfusion injury due to reactive oxygen species. Signup and view all the answers

What is the primary pathology characteristic of allergic contact dermatitis?

T cell mediated hypersensitivity reaction. Signup and view all the answers

What is a common risk factor for the development of pressure injuries?

Prolonged immobilization. Signup and view all the answers

Which of the following is a function of papillary capillaries?

Temperature regulation by blood flow. Signup and view all the answers

What visual change is commonly associated with skin aging?

Formation of deep creases and lines. Signup and view all the answers

What mechanism primarily mediates the immune response in allergic contact dermatitis?

Type IV hypersensitivity Signup and view all the answers

What is an example of a common irritant that can lead to irritant contact dermatitis?

Nickel in jewelry Signup and view all the answers

In psoriasis, what is responsible for the rapid turnover of skin cells?

Keratinocyte hyperplasia Signup and view all the answers

Which characteristic symptom differentiates acne rosacea from acne vulgaris?

Chronic vasodilation Signup and view all the answers

What defines discoid lupus erythematosus?

A genetically predisposed, autoimmune skin disorder Signup and view all the answers

What is a key symptom of herpes zoster (shingles)?

Linear stripes of lesions Signup and view all the answers

What causes the lesions seen in Kaposi sarcoma?

Opportunistic infection by HSV-8 Signup and view all the answers

Which treatment is most effective for Lyme disease if administered early?

Early antibiotics Signup and view all the answers

What primary factor contributes to the formation of acne vulgaris?

Blocked sebaceous follicles Signup and view all the answers

Which statement about herpes simplex virus (HSV) is accurate?

HSV can remain latent in neurons Signup and view all the answers

What causes the tenderness and bleeding associated with psoriasis plaques?

Presence of immature skin cells Signup and view all the answers

What is the mechanism of action that leads to inflammation in irritant contact dermatitis?

Direct injury to the skin Signup and view all the answers

The butterfly rash is a symptom commonly associated with which condition?

Discoid lupus erythematosus Signup and view all the answers

What occurs during the reactivation of the varicella-zoster virus?

It leads to a painful rash along dermatomes. Signup and view all the answers

Which factor significantly increases the risk of developing Kaposi Sarcoma?

Infection with HSV-8 in immunocompromised individuals. Signup and view all the answers

What is the primary characteristic of Lyme Disease?

It is characterized by a bullseye rash. Signup and view all the answers

During hypoventilation, which acid-base imbalance is most likely to occur?

Respiratory acidosis. Signup and view all the answers

Which epigenetic mechanism decreases gene expression by adding methyl groups?

DNA methylation. Signup and view all the answers

What impact do lifestyle choices have on epigenetic modifications?

They can modify gene expression patterns. Signup and view all the answers

How does the stratum corneum differ between darker and lighter skin?

It has more layers in darker skin. Signup and view all the answers

What physiological characteristic is associated with increased melanin production?

Increased activity of the enzyme tyrosinase. Signup and view all the answers

What is a significant consequence of increased DNA methylation?

Decreased access to DNA for transcription. Signup and view all the answers

How does black skin generally respond to UV rays compared to lighter skin?

It has lower photosensitivity and offers more UV protection. Signup and view all the answers

What is a possible outcome of postherpetic neuralgia?

Chronic pain following resolution of the rash. Signup and view all the answers

What is the primary way that genomic imprinting affects gene expression?

By silencing one allele of a gene based on parental origin. Signup and view all the answers

Which skin trait varies with skin pigmentation?

Degree of skin elasticity. Signup and view all the answers

Which statement accurately addresses the concept of environmental influence on epigenetics?

Lifestyle choices can induce epigenetic modifications, potentially affecting offspring. Signup and view all the answers

What is the primary reason someone should avoid drinking seawater in a survival situation?

Seawater is hypertonic compared to body cells. Signup and view all the answers

Which mechanism explains how nutrition can influence gene expression?

Nutritional factors can promote gene demethylation. Signup and view all the answers

What is the significance of the epidermis layer in preventing DNA damage?

It protects against UV ray exposure. Signup and view all the answers

What is the correct role of DNA polymerase during DNA replication?

Perform proofreading and base pairing. Signup and view all the answers

Which best describes a silent mutation?

A change in DNA that does not alter amino acid sequence. Signup and view all the answers

How many chromosomes do somatic cells contain?

46 chromosomes. Signup and view all the answers

What condition results from the deletion of the short arm of chromosome 5?

Cri du chat syndrome. Signup and view all the answers

What is the expected outcome of autosomal dominant gene transmission?

Equal transmission rates between genders. Signup and view all the answers

Which statement accurately reflects the definition of epigenetics?

The study of gene function without altering DNA sequence. Signup and view all the answers

Which modification is NOT considered an epigenetic mechanism?

RNA polymerase activity. Signup and view all the answers

What is the potential impact of healthy nutrition on gene methylation?

It promotes gene silencing through demethylation. Signup and view all the answers

What occurs to a cell when it experiences dehydration due to drinking seawater?

Cells lose water and shrivel. Signup and view all the answers

What type of mutation could potentially lead to a frameshift?

Insertion or deletion mutation. Signup and view all the answers

What distinguishes somatic cells from gametes?

Somatic cells contain two sets of chromosomes. Signup and view all the answers

Study Notes

Acid-Base Regulation

Body maintains pH through equilibrium, regulated by the reaction: CO2 + H2O ↔ H2CO3 ↔ HCO3− + H+.
Le Chatelier's principle dictates that the reaction shifts toward the area with the least concentration to maintain equilibrium.
Disorders arise from imbalances in CO2 and HCO3− levels.
Respiratory acidosis/alkalosis involve CO2 levels; metabolic acidosis/alkalosis affect HCO3−.
pH restoration is prioritized before addressing CO2 and HCO3− levels.

Epigenetics

Epigenetics studies changes in gene expression without altering the DNA sequence.
Key mechanisms include DNA methylation (decreasing gene expression by adding a methyl group).
Other modifications include histone modifications and RNA-based mechanisms.
Environmental factors (e.g., smoking, exercise) influence epigenetic modifications.
Epigenetic changes can be transmitted through generations (limited and not the same as genetic transmission).

Epigenetics and Pathology

Epigenetic modifications can result in diverse outcomes even with the same genetic abnormality (e.g., 4-Mbp deletion PWS-AS region).
Genomic imprinting influences gene expression based on parental origin.
X inactivation in females (inactivating one X) is a form of genomic imprinting.
Epigenetic changes can be reversible and are tied to lifestyle, carcinogen exposure, and occupational hazards. Cancer development can be related to epigenetic processes.

Skin Physiology

Skin structure is similar across different skin tones.
Darker skin generally has a more compact stratum corneum (e.g., larger number of layers & more densely packed).
Darker skin has greater lipid content and moisture retention, resulting in reduced chemical penetrance.
Photosensitivity and erythema are less visible and severity in people with darker skin.
There's no relationship between skin tone and sweat glands.
Enzyme activity (tyrosinase) dictates melanin production rate, therefore skin tones. Lighter skin can darken with enhanced tyrosinase activity (e.g., through use of retinoic acid).
Pulse oximeters can have challenges in accurately measuring oxygen saturation for darker skin tones.

Acid-Base Imbalances (MCQ)

Respiratory alkalosis: Increased CO2 and decreased HCO3- (A).
Respiratory acidosis: Decreased CO2 and increased HCO3- (B).
Metabolic acidosis:
Metabolic alkalosis:

Module 2: Basic Genetics and Integumentary System (8 questions)

DNA Polymerase: Function is to perform base pairing in DNA replication.
Silent Mutation: A change in DNA sequence without altering the coded amino acid.
Somatic Cell: Contains 46 chromosomes and is diploid.
Cri du Chat Syndrome: Deletion on chromosome 5 short arm.
Autosomal Dominant: Affected parent transmits the gene to approximately half of their children.
Epigenetics: Study of factors affecting gene expression without changing the DNA sequence (e.g., methylation, histone modifications).
Epigenetic Modifications: Influenced by diet, lifestyle, and can be reversible.

Environmental Influences on Health

Polygenic Traits: Affected by multiple genes. Height is an example of a polygenic trait affecting multiple gene expressions.
Environmental factors significantly influence polygenic trait expression (e.g., better nutrition and living conditions can increase average height over time).
Epigenetics: Study of how environmental factors influence gene expression.
Environmental and genetic factors combined create complexity in disease, requiring consideration of both for proper treatment.

Twin Studies and Adoption Studies

Twin Studies: Examine the contribution of genetics and environment to traits. Identical (monozygotic) twins share 100% genes, fraternal (dizygotic) twins share 50%. High concordance rates in monozygotic twins suggest a strong genetic influence.
Adoption Studies: Compare adopted individuals to both biological and adoptive families to isolate environmental impact on traits.

Dehydration and Ocean Survival

Drinking seawater is detrimental, as it's hypertonic to human cells, leading to cellular dehydration.
Urine is less hyperosmolar and thus a better hydration source in survival situations.

Nutrition and Epigenetics

Nutritious food promotes expression of healthy genes via demethylation.

Burns and DNA Mutations

Significant burns expose internal tissues to UV light.
Damaged epidermis compromises the barrier against UV light, elevating the risk of DNA damage.

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Description

Test your knowledge on the structure of DNA, the role of RNA polymerase, and key concepts of cell division including mitosis and meiosis. This quiz covers essential genetic concepts and mutations that affect protein synthesis and gene expression.