Cancer, DNA Replication, and Cell Cycle

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Questions and Answers

What is the result of crossing over during meiosis?

Formation of genetically identical gametes

Exchange of genetic material between homologous chromosomes (correct)

Double the number of chromosomes

No change in chromosome type

What is the main purpose of meiosis?

To produce identical daughter cells

To produce gametes with half the chromosome number (correct)

To increase the number of chromosomes

To repair damaged cells

Which statement accurately describes radiation therapy?

Uses low-energy particles to enhance cell division

Primarily targets cancerous cells without affecting normal cells

Can repair damaged cells in the stomach lining

Destroys cancer cells by damaging their DNA (correct)

What is one outcome of random alignment during meiosis?

Variation in genetic combinations of gametes Signup and view all the answers

What occurs during nondisjunction in meiosis?

Failure of homologous pairs to separate Signup and view all the answers

What is a notable difference between mitosis and meiosis?

Mitosis occurs in somatic cells, meiosis in germ cells Signup and view all the answers

Why is it significant that gametes are haploid?

They contribute to genetic variation upon fertilization Signup and view all the answers

In what stage does crossing over occur during meiosis?

Prophase I Signup and view all the answers

What is the role of crossing over during Prophase I of Meiosis?

It allows for genetic material exchange between homologous chromosomes. Signup and view all the answers

What describes a homozygous genotype?

Both alleles for a gene are identical. Signup and view all the answers

Which of the following statements about dizygotic twins is correct?

They are formed from two different sperm and two different eggs. Signup and view all the answers

Which method of genetic diversity involves the random pairing of chromosomes?

Independent Assortment Signup and view all the answers

What is a characteristic of a recessive phenotype?

Only seen when homozygous for the recessive allele. Signup and view all the answers

In a genetic cross involving incomplete dominance, what will the phenotype of the heterozygote typically display?

An intermediate phenotype between the homozygotes. Signup and view all the answers

Which of the following best defines a phenotype?

The observable traits of an individual. Signup and view all the answers

What is the outcome of random fertilization in terms of genetic diversity?

It results in approximately 64 trillion different combinations of gametes. Signup and view all the answers

What characterizes a malignant tumor?

It invades surrounding tissues. Signup and view all the answers

What is the role of tumor suppressor genes in the cell cycle?

They inspect newly replicated DNA. Signup and view all the answers

What is metastasis in the context of cancer?

The spread of cancer cells to other parts of the body. Signup and view all the answers

Which of the following treatments selectively kill dividing cells?

Chemotherapy. Signup and view all the answers

What distinguishes a benign tumor from a malignant tumor?

Benign tumors are non-cancerous. Signup and view all the answers

What is a carcinogen?

A substance that increases cancer risk. Signup and view all the answers

During which phase of mitosis do chromosomes align at the cell's equator?

Metaphase. Signup and view all the answers

What must occur for a cell to proceed past the G1 checkpoint?

It must have sufficient growth factors. Signup and view all the answers

What is the primary function of RNA polymerase during transcription?

To bind to the promoter region of the gene Signup and view all the answers

Which of the following statements accurately describes a key difference between DNA and RNA?

RNA nucleotides contain ribose, while DNA nucleotides contain deoxyribose Signup and view all the answers

How can mutations affect protein synthesis?

By altering the correct order of amino acids in a protein Signup and view all the answers

What is the role of restriction enzymes in creating recombinant proteins?

To cut DNA at specific sequences Signup and view all the answers

What is a transgenic organism?

An organism with DNA from multiple species incorporated into its genome Signup and view all the answers

Why do different cell types, like nerve and muscle cells, express different genes?

Due to the selective regulation of gene expression Signup and view all the answers

What characterizes stem cells?

They are undifferentiated and can grow into multiple cell types Signup and view all the answers

What is a possible outcome of a neutral mutation?

No significant change to the protein function Signup and view all the answers

Which statement correctly describes Y-linked inheritance?

Only males exhibit Y-linked traits. Signup and view all the answers

What role does the SRY region of the Y chromosome play in sexual development?

It encodes a testis-determining factor necessary for male development. Signup and view all the answers

Which of the following accurately defines a polygenic trait?

A trait that results from the interaction of two or more genes. Signup and view all the answers

What is a quantitative trait?

A trait displaying continuous variation among individuals. Signup and view all the answers

In the context of genetic engineering, which statement is true?

It may involve moving genes between different organisms. Signup and view all the answers

Which of the following correctly describes heritability?

The variability of a trait among individuals due to genetic differences. Signup and view all the answers

What does the term epigenetics refer to?

Mechanisms that change gene expression without altering the DNA sequence. Signup and view all the answers

Which step is NOT part of the protein synthesis process?

Modification of RNA by adding nucleotides. Signup and view all the answers

Study Notes

Cancer

Cancer is uncontrolled cell division that forms a tumor, which eventually invades surrounding tissues.
Benign tumors are not cancerous and do not invade surrounding tissues.
Malignant tumors are cancerous and invade surrounding tissues.
Metastasis occurs when cancer cells break away from a malignant tumor and start another tumor in another part of the body.
Cancer cells differ from normal cells because they divide when they shouldn’t, invade surrounding tissues, and move to other locations in the body.
Carcinogens are substances that can increase the risk of cancer.
Synergistic effects occur when two or more carcinogens have a greater risk than each activity alone.

DNA Replication

DNA replication involves the creation of two identical DNA molecules from one original DNA molecule.
Replication occurs in the nucleus of a cell.
Enzymes involved in DNA replication include Helicase, DNA polymerase, Primase, Ligase, and Topoisomerase.

Cell Cycle

Mitosis is the process of cell division that produces two genetically identical daughter cells.
Mitosis involves four phases: prophase, metaphase, anaphase, and telophase.
The purpose of mitosis is for asexual reproduction or to make more body cells.
The cell cycle includes checkpoints that ensure proper DNA replication and cell division.
Tumor suppressor genes produce proteins that inspect newly replicated DNA for errors.

Cancer Detection and Treatment

Chemotherapy involves using chemicals to treat cancer by selectively killing dividing cells.
Radiation therapy uses high-energy particles to damage the DNA of cancer cells, preventing them from dividing and growing.

Meiosis

Meiosis is a type of cell division that occurs in the gonads to produce gametes (sperm and eggs).
Meiosis produces four daughter cells that are not genetically identical to each other or to the parent cell.
Meiosis reduces the number of chromosomes in each gamete by half.
Crossing over, a process that involves the exchange of equivalent portions of chromosomes, occurs during Prophase I of meiosis.
Random alignment of chromosomes during metaphase I contributes to genetic diversity in offspring.
Nondisjunction is the failure of homologous pairs to separate normally during meiosis I, leading to gametes with an abnormal number of chromosomes.

Human Life Cycle

Adults produce gametes through meiosis in their gonads.
Fertilization of an egg cell by a sperm cell forms a single-celled zygote..
Repeated cell division leads to the development of an embryo.
The embryo grows into a fetus and after birth, the individual continues to grow into adulthood.

Genetics

Genes are segments of DNA that code for proteins.
Chromosomes are analogous to pages in the instruction manual, containing thousands of genes.
Alleles are different versions of genes that arise from mutations in DNA.

Genetic Diversity

Genetic diversity in offspring is produced in five ways: random mutations, crossing over, segregation of chromosomes, independent assortment of chromosomes, and random fertilization.
Monozygotic twins are formed from one sperm and one egg, while dizygotic twins are formed from two different sperm and two different eggs.

Genotype and Phenotype

Phenotype refers to the physical traits of an individual, while genotype describes the alleles for a particular gene.
Homozygous genotypes have two identical alleles for a gene, while heterozygous genotypes have two different alleles.
A recessive allele's phenotype is only seen when homozygous, while a dominant allele's phenotype is seen when homozygous or heterozygous.

Specific Genetic Cross Types:

Incomplete dominance occurs when two copies of the dominant allele are needed to see the full phenotype. The heterozygous phenotype is intermediate to the homozygotes, such as flower color in snapdragons.
Codominance occurs when neither allele is dominant to the other, and the heterozygote shows both traits at once, such as coat color in cattle.
Sex-linked genes are located on sex chromosomes, X-linked genes are on the X chromosome, and Y-linked genes are on the Y chromosome.
Males inherit their X chromosome from their mothers.
Males are more likely to express recessive X-linked traits than females.
Only females can be carriers of X-linked recessive traits.

Sex Determination

Humans have 22 pairs of autosomes and one pair of sex chromosomes.
Females have two X chromosomes, while males have one X and one Y chromosome.
The SRY gene on the Y chromosome encodes a testis-determining factor (TDF), which is essential for male sexual development.

Pedigree

Pedigrees are diagrams that trace the inheritance of traits through generations.

Quantitative Traits

Quantitative traits show continuous variation and are influenced by both genetic and environmental differences.
Examples of quantitative traits include height, weight, and intelligence.

Epigenetics

Epigenetics is the study of how environmental factors can influence gene expression without affecting DNA sequence.

Genetic Engineering

Genetic engineering involves altering hereditary traits by molecular techniques, modifying or moving genes between organisms.

Protein Synthesis

Protein synthesis involves using instructions carried on a gene to create proteins.
Transcription occurs in the nucleus and involves RNA polymerase binding to the promoter region of a gene, then zipping down the length of the gene, matching RNA nucleotides with complementary DNA nucleotides.

DNA vs. RNA

DNA is double-stranded, composed of deoxyribose, phosphate, and four nitrogenous bases: adenine, thymine, guanine, and cytosine.
RNA is single-stranded, composed of ribose, phosphate, and four nitrogenous bases: adenine, uracil, guanine, and cytosine.

Mutations

Mutations are changes in the genetic sequence that can disrupt the end product of protein synthesis, affecting protein function.

Gene Expression

Different cell types express different genes, allowing them to perform specialized functions.
Regulation of gene expression involves turning genes on or off.
Mutations in genes that are turned on in a particular cell are more likely to be noticeable.

Recombinant Proteins

Recombinant proteins are proteins created by combining genes from different organisms.
Recombinant proteins are used in various applications, such as medication and agricultural products.

Genetically Modified Organisms (GMOs)

Transgenic organisms, also known as GMOs, are organisms that have incorporated a gene from another organism into their genome.
GMOs have numerous potential benefits and drawbacks, including increased crop yields, enhanced nutritional content, and potential risks to biodiversity.

Stem Cells

Stem cells are undifferentiated cells that have the potential to develop into various cell types and tissues.
Stem cells are a promising area of research for treating degenerative diseases such as Alzheimer's, Parkinson's, multiple sclerosis, and organ failure.

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Description

This quiz covers essential topics in biology, focusing on cancer, DNA replication, and the cell cycle. You will explore the mechanisms of tumor formation, the process of DNA replication, and the stages of the cell cycle, including important enzymes involved. Test your knowledge and understanding of these critical biological concepts.