Biology Chapter: Cell Division and Genetics

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Questions and Answers

What is the main difference between cytokinesis in plant and animal cells?

Plant cells develop a cell plate to divide. (correct)

In animal cells, a cell plate develops.

Animal cells use growth factors to facilitate division.

In plant cells, a cleavage furrow forms.

Which factor is NOT considered to influence the rate of cell division?

Age of the cell (correct)

Surface attachment

Growth factors

Environmental factors

How many chromosomes do human somatic cells typically contain?

46 (correct)

What process enhances genetic diversity during meiosis?

Independent orientation of chromosomes Signup and view all the answers

What is the outcome of nondisjunction during meiosis?

Abnormal chromosome count Signup and view all the answers

What does a karyotype provide?

A photographic inventory of chromosomes Signup and view all the answers

Which statement about meiosis is true?

Meiosis II resembles mitosis in its process. Signup and view all the answers

What condition is caused by an extra copy of chromosome 21?

Down syndrome Signup and view all the answers

What primarily drives sympatric speciation?

Chromosome duplication Signup and view all the answers

How do prezygotic and postzygotic barriers primarily differ?

Prezygotic barriers prevent fertilization, while postzygotic barriers affect offspring viability. Signup and view all the answers

Which concept is NOT a definition of a species?

Phenotypical Signup and view all the answers

What is a potential outcome when two closely related species meet in a hybrid zone?

Strengthening or weakening of reproductive barriers Signup and view all the answers

Which scenario best illustrates adaptive radiation?

Finches developing varied beak shapes on different islands to exploit unique food sources. Signup and view all the answers

What is the genetic basis for Klinefelter syndrome and Turner syndrome?

Abnormal numbers of sex chromosomes Signup and view all the answers

Which term describes a heritable feature that varies among individuals?

Character Signup and view all the answers

What does Mendel's Law of Segregation state?

Alleles separate during gamete formation Signup and view all the answers

In a testcross, what type of individual is mated with an individual of unknown genotype?

A homozygous recessive individual Signup and view all the answers

What is the primary focus of genetic testing services?

To provide extensive genetic information Signup and view all the answers

What is the outcome ratio for a monohybrid cross involving heterozygous individuals?

3:1 Signup and view all the answers

Which rule calculates the probability of two independent events occurring together in genetics?

Rule of Multiplication Signup and view all the answers

What does Mendel's Law of Independent Assortment state?

Allele pairs segregate independently during gamete formation Signup and view all the answers

What is the result of incomplete dominance in offspring?

Offspring exhibit traits that are a blend of parental phenotypes. Signup and view all the answers

What is pleiotropy as exemplified by sickle-cell disease?

One gene influences multiple phenotypic traits. Signup and view all the answers

Which statement best describes the chromosome theory of inheritance?

Genes are located on chromosomes, which segregate during meiosis. Signup and view all the answers

How does crossing over during meiosis affect inheritance?

It generates new allele combinations, leading to recombinant gametes. Signup and view all the answers

How do linked genes affect inheritance patterns?

They are inherited together more often due to proximity on the same chromosome. Signup and view all the answers

Which of the following best describes polygenic inheritance?

Multiple genes influence a single trait. Signup and view all the answers

What does codominance illustrate in the ABO blood group system?

Both IA and IB alleles are expressed in individuals with type AB blood. Signup and view all the answers

How do environmental factors influence traits?

They can shape traits that are influenced by both genetics and the environment. Signup and view all the answers

What type of natural selection favors both extremes over intermediates?

Disruptive Selection Signup and view all the answers

Which of the following concepts defines a species primarily by its ability to interbreed and produce fertile offspring?

Biological Species Concept Signup and view all the answers

In which form of selection do individuals of one sex choose mates based on specific traits?

Intersexual Selection Signup and view all the answers

Which barrier prevents mating or fertilization between species?

Prezygotic Barriers Signup and view all the answers

Which of the following is NOT a mechanism of allopatric speciation?

Ecological Isolation Signup and view all the answers

Which of the following statements is true about sexual dimorphism?

It results from intersexual selection. Signup and view all the answers

Which concept focuses on the smallest group sharing a common ancestor?

Phylogenetic Species Concept Signup and view all the answers

Natural selection cannot produce perfection because of which of the following reasons?

It is constrained by existing variations. Signup and view all the answers

What do transitional fossils demonstrate in evolutionary biology?

They link extinct species to living species, revealing evolutionary sequences. Signup and view all the answers

What is the primary function of natural selection in evolution?

To favor traits that enhance survival and reproduction. Signup and view all the answers

Which of the following is NOT one of the conditions for a population to be in Hardy-Weinberg equilibrium?

Presence of mutations. Signup and view all the answers

What does homology refer to in evolutionary biology?

Similarities in traits due to common ancestry. Signup and view all the answers

What is one of the effects of genetic drift on a population?

It randomly reduces genetic diversity. Signup and view all the answers

Which statement about evolution and populations is correct?

Populations evolve through changes in gene pools. Signup and view all the answers

Which of the following does NOT describe a source of genetic variation?

Uniform reproduction across a population. Signup and view all the answers

How do evolutionary trees illustrate relationships among species?

By representing relationships and branching sequences based on homologies. Signup and view all the answers

Study Notes

General Concepts

Life's properties include order, reproduction, growth, development, energy processing, regulation, response to the environment, and evolutionary adaptation.
Life's diversity is organized into three domains: Bacteria, Archaea, and Eukarya. Bacteria and Archaea are prokaryotic, meaning they lack a nucleus and membrane-bound organelles. Eukarya includes organisms with a nucleus and membrane-bound organelles, like plants, animals, fungi, and protists.
Humans are classified in the domain Eukarya and the kingdom Animalia.
Science uses an evidence-based process of inquiry to investigate the natural world. This involves observations, hypotheses, predictions, tests of hypotheses (experiments or additional observations), and analysis of data.
A scientific theory is a well-supported explanation of a natural phenomenon based on evidence and repeated testing.

The Process of Science

Researchers often manipulate one component of a system and observe the effects.
- Independent variable: the factor being manipulated.
- Dependent variable: the factor being measured to gauge the outcome.
- Controlled experiment: compares an experimental group (with the manipulated variable) to a control group (without the manipulated variable).

Five Unifying Themes in Biology

Life is distinguished by unity and diversity.
Evolution is the unifying explanation for this unity and diversity.
Darwin synthesized the theory of evolution by natural selection. Natural selection is the process where organisms with traits better suited to their environment are more likely to survive and reproduce, passing those traits to their offspring.

Notes for Chapter 2

DNA provides the blueprint for proteins and directs cellular activities.
Flow of information: DNA → RNA → protein
Ecosystems involve matter cycling through producers, consumers, and decomposers. The process starts and ends in the environment.
The study of life extends from molecular to global scales.
All systems have emergent properties that are the result of interactions between components.
Scientists analyze these interactions using systems biology.

Notes for Chapter 3

Matter is composed of elements and elements are made up of atoms.
About 25 elements are essential for human life.
Four elements (oxygen, carbon, hydrogen, nitrogen) make up approximately 96% of the weight of most organisms.
Atoms are composed of subatomic particles: protons (in the nucleus), neutrons (in the nucleus), and electrons (orbiting the nucleus).
The unique number of protons defines an element's atomic number.
Atomic mass is approximately equal to the sum of protons and neutrons.
Isotopes are variations of an element with different numbers of neutrons.
Radioactive isotopes can be used as tracers to monitor atoms in living organisms.
Electrons fill electron shells around the nucleus, and interactions between electrons of different atoms result in chemical bonds.
- Ionic bonds: result from the transfer of electrons (one atom gains an electron, one atom loses).
- Covalent bonds: result from the sharing of electrons.
- Nonpolar covalent bond: electrons are shared equally
- Polar covalent bond: electrons are not shared equally (one atom is more electronegative)
- Hydrogen bonds: relatively weak bonds between a hydrogen atom (covalently bonded to an electronegative atom like oxygen or nitrogen) and another electronegative atom.
Water's unique properties are due to its polarity and ability to form hydrogen bonds. These properties include cohesion, adhesion, surface tension, high specific heat, evaporative cooling, versatility as a solvent, and density differences.
The study of life extends from the microscopic scale to the global scale.

Notes for Chapter 4

Microscopes reveal cell structures.
Cell theory states that all organisms are composed of cells and that all cells arise from pre-existing cells.
Cell size is related to its surface area-to-volume ratio, which is critical for efficient material exchange (the larger the area, the better).
The plasma membrane is a phospholipid bilayer with embedded proteins that regulates transport
Prokaryotic cells lack a nucleus and membrane-bound organelles and are generally smaller.
Eukaryotic cells have membrane-bound organelles and are larger.
Eukaryotic cells are grouped by function into four categories: genetic control (nucleus), manufacturing, distribution, breakdown (endomembrane system), energy processing (mitochondria, chloroplasts), and structural support, movement, and communication (cytoskeleton).

Notes for Chapter 5

Cellular respiration is a process of breaking down sugars for energy in the presence of oxygen.
ATP is the primary energy source for cells.
Brown fat cells produce heat without ATP through a specialized respiration process.
All life depends on energy, ultimately sourced from the sun.
Photosynthesis converts carbon dioxide and water into organic molecules while releasing oxygen, a process that is the opposite of cellular respiration.

Notes for Chapter 6

Cellular respiration occurs through a series of reactions, from glycolysis to the Krebs cycle to oxidative phosphorylation, leading to ATP production.
NADH and FADH2 are electron carriers that transport electrons to the electron transport chain in oxidative phosphorylation, a crucial part of ATP creation.
The process of oxidative phosphorylation creates most of the ATP in cellular respiration.

Notes for Chapter 7

Anaerobic respiration (fermentation) occurs in the absence of oxygen
NAD+ is regenerated during fermentation, allowing glycolysis to continue.
Cellular respiration (in the presence of oxygen) has higher ATP yields compared to fermentation.

Notes for Chapter 8

Cell division is essential for reproduction and growth and development in multicellular organisms.
Prokaryotes divide through binary fission.
Eukaryotes divide through the cell cycle, including mitosis (nuclear division) and cytokinesis (cytoplasmic division).
Cell division is a tightly regulated process. Checkpoints within the cell cycle ensure accuracy during each stage.
Cancer results from uncontrolled cell division. There are many factors that promote or restrict cell growth, and issues relating to their control impact on the cell cycle.

Notes for Chapter 9

Genes are the fundamental units of heredity
The chromosome theory of inheritance explains how traits are passed down through genes' location on chromosomes. This was pioneered by Mendel, whose research led to the discovery of important principles and patterns in inheritance, including the law of segregation and the law of independent assortment.

Notes for Chapter 10

Genes are physically located on chromosomes.
Linked genes tend to be inherited together because they are close together on the same chromosome
Crossing over contributes variation and recombining genes during the formation of gametes
In many species, sex is determined by sex chromosomes like X and Y.
X-linked traits have different inheritance patterns than those on autosomal chromosomes.

Notes for Chapter 11

DNA and RNA are nucleic acids composed of nucleotides.
DNA has a double helix structure, while RNA is single-stranded.
DNA's bases are adenine, thymine, cytosine, and guanine.
RNA's bases are adenine, uracil, cytosine, and guanine
DNA replication is a semiconservative process. Each new DNA molecule is composed of one original strand and one new complementary strand.
DNA synthesis is facilitated by enzymes like DNA polymerase and ligase.
Transcription is the synthesis of RNA under the direction of DNA. Translation is the synthesis of protein under the direction of RNA.

Notes for Chapter 13

Evolution explains the diversity of life, and the environment has a large influence on evolutionary changes.
Darwin's theory of evolution posits that species descend from common ancestors and adapt to their environment over time
Natural selection is the key mechanism of evolution. In this process, individuals with traits suited to their environment are more likely to survive and reproduce, passing on those advantageous traits.
Fossils provide evidence of past life forms and transitions between species.
Homologies (similarities in traits due to common ancestry) provide further evidence of evolution. Analogous structures are examples of similar traits used for the same purpose, but are not due to shared ancestry.
Evolutionary trees depict the relationships and branching sequences among species based on shared characteristics.

Notes for Chapter 14

Microevolution is the change in gene frequencies within a population over time. It's a smaller scale of evolutionary change, while speciation refers to the formation of new species from existing ones.
Speciation occurs when a population of a species becomes reproductively isolated from other populations of the same species. This isolation can occur by geographic separation (allopatric speciation), or by other mechanisms (sympatric speciation).
Reproductive barriers are mechanisms that prevent interbreeding between different species or populations, maintaining their separation.

Notes for Chapter 15

Natural selection occurs through the process of variations in heritable characteristics, and the favoring of those characteristics that increase reproductive success within an environment.
Some examples of selection patterns include stabilizing selection (favoring intermediate phenotypes), directional selection (favoring one extreme phenotype), and disruptive selection (favoring both extreme phenotypes).
Sexual selection is a form of natural selection that focuses on traits that increase reproductive success, such as attracting a mate or competing with rivals.
Microevolution is concerned with change within a species, while macroevolution describes the larger picture of speciation and the broader diversity of life.
The process of speciation can happen gradually or through fast changes. The exact mechanism of speciation is very complex and occurs alongside other evolutionary processes or constraints.

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Description

Test your knowledge on key concepts in cell division, meiosis, and genetic diversity with this quiz. Explore differences between plant and animal cells, the mechanics of nondisjunction, and the principles outlined by Mendel. This quiz will challenge your understanding of species definitions and speciation processes.