Cell Structure and Functions Quiz

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Questions and Answers

What is a key difference between prokaryotic and eukaryotic cells?

Prokaryotic cells lack a nucleus, while eukaryotic cells possess one. (correct)

Eukaryotic cells have circular DNA, while prokaryotic cells have linear DNA.

Prokaryotic cells are typically larger in size compared to eukaryotic cells.

Eukaryotic cells have a cell wall in all types, while prokaryotic cells do not.

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

Prophase

Anaphase

Metaphase (correct)

Telophase

Which structure is unique to plant cells during cytokinesis?

Nuclear envelope

Cleavage furrow

Cell plate (correct)

Centrosome

What describes the composition of a chromosome?

DNA and proteins Signup and view all the answers

Which of the following correctly describes sister chromatids?

Duplicated chromosomes still connected at the centromere. Signup and view all the answers

What type of ribonucleic acid carries the genetic information from DNA to the ribosome?

mRNA Signup and view all the answers

Which term describes the haploid number of chromosomes in humans?

23 Signup and view all the answers

What is the primary outcome of meiosis?

Four genetically unique cells are produced Signup and view all the answers

What is a primary function of the mitochondrion?

Energy production Signup and view all the answers

Which process occurs during Meiosis I and contributes to genetic diversity?

Crossing over of homologous chromosomes Signup and view all the answers

How do gametes differ from somatic cells in terms of chromosome number?

Gametes are haploid while somatic cells are diploid Signup and view all the answers

What does independent assortment during meiosis refer to?

The random distribution of alleles from different genes Signup and view all the answers

What genetic configuration results from a true-breeding line?

Homozygous genotype Signup and view all the answers

Which term describes the physical expression of a genetic trait?

Phenotype Signup and view all the answers

In a genetic cross of Aa x Aa, what is the probability of obtaining a homozygous recessive offspring?

25% Signup and view all the answers

What term is used for the chromosomes that are paired during meiosis?

Homologous chromosomes Signup and view all the answers

What does Mendel's principle of segregation state?

Alleles of a gene segregate into separate gametes during meiosis. Signup and view all the answers

How do genes on separate chromosomes exhibit inheritance patterns according to Mendel's laws?

They exhibit independent assortment during meiosis. Signup and view all the answers

Which of the following correctly describes a test cross?

Crossing a heterozygous individual with a homozygous recessive individual. Signup and view all the answers

What is the expected phenotypic ratio for a monohybrid cross?

3:1 Signup and view all the answers

In the context of genetics, what does co-dominance refer to?

Both alleles are expressed equally in the phenotype. Signup and view all the answers

What does the addition rule of probability help determine in genetic crosses?

The probability of at least one of several events occurring. Signup and view all the answers

What indicates an X-linked trait in genetic inheritance?

The trait is inherited only from the mother. Signup and view all the answers

During a genetic cross, how can actual data be used to test a hypothesis?

By observing the results and determining if they align with predictions. Signup and view all the answers

Study Notes

Cell Structure

Three Domains of Life: Bacteria, Archaea, and Eukarya
Prokaryotes: Bacteria and Archaea, lack a nucleus and membrane-bound organelles
Eukaryotes: Eukarya, have a nucleus and membrane-bound organelles
Similarities between Prokaryotes and Eukaryotes: Both have DNA, ribosomes, cell membranes, and cytoplasm
Differences between Prokaryotes and Eukaryotes: Eukaryotes have a nucleus, membrane-bound organelles, and linear DNA, prokaryotes have a nucleoid, circular DNA, and lack membrane-bound organelles
Cell Wall: A rigid outer layer that provides structural support and protection, found in plants, fungi, and bacteria
Plasma Membrane: A selectively permeable phospholipid bilayer that regulates the passage of molecules in and out of the cell, found in all cell types
Nucleus: A membrane-bound organelle containing DNA, found in eukaryotes
Nuclear Envelope: A double membrane surrounding the nucleus, regulates the movement of molecules between the nucleus and cytoplasm, found in eukaryotes
Nucleolus: A region within the nucleus where ribosomal RNA is synthesized, found in eukaryotes
Nucleoid: A region within the cytoplasm where DNA is localized in prokaryotes, not membrane-bound
Mitochondrion (Mitochondria): Site of cellular respiration, responsible for ATP production, found in eukaryotes
Chloroplast: Site of photosynthesis, found in plants and algae
Cytoskeleton: A network of protein filaments that provides structural support, helps with movement, and assists in cell division, found in both prokaryotes and eukaryotes
- Microtubules: Hollow tubes made of tubulin, involved in cell shape, movement of organelles, and chromosome separation during cell division
- Microfilaments: Solid rods made of actin, involved in cell shape, muscle contraction, and cytoplasmic streaming
Ribosomes: Sites of protein synthesis, found in both prokaryotes and eukaryotes
Plasmids: Small circular DNA molecules found in prokaryotes, often carry genes for antibiotic resistance

Mitosis

Mitotic Cell Cycle: A series of events that lead to cell division, including:
- G1 Phase: Cell growth and prepares for DNA replication
- S Phase: DNA replication occurs
- G2 Phase: Cell prepares for mitosis
- M Phase: Mitosis and cytokinesis occur
Basic Results of Mitosis: Two genetically identical daughter cells, each with the same number of chromosomes as the original cell
Chromosome Structure:
- Unreplicated Chromosome: A single, linear molecule of DNA
- Replicated Chromosome: Two identical sister chromatids joined at the centromere
- Centromere: The region where sister chromatids are attached
Terminology:
- Sister Chromatids: Two identical copies of a chromosome held together at the centromere
- Non-Sister Chromatids: Chromatids from homologous chromosomes
- Homologous Chromosomes: Chromosomes that carry the same genes in the same order
- Non-Homologous Chromosomes: Chromosomes that carry different genes
Ploidy Level:
- Diploid (2n): Cells containing two sets of chromosomes
- Haploid (n): Cells containg one set of chromosomes
Functions of Mitosis:
- Growth and Development: Increases the number of cells in an organism
- Repair and Renewal: Replaces damaged or lost cells
- Asexual Reproduction: Some organisms reproduce asexually through mitosis
Stages of Mitosis:
- Prophase: Chromosomes condense, nuclear envelope breaks down, mitotic spindle forms
- Prometaphase: Chromosomes align at the metaphase plate, mitotic spindle fibers attach to kinetochores
- Metaphase: Chromosomes align at the metaphase plate, spindle fibers are fully attached
- Anaphase: Sister chromatids separate and move to opposite poles
- Telophase: Chromosomes decondense, nuclear envelope reforms, cytokinesis begins
Differences between Animal and Plant Cells in Mitosis:
- Animal Cells: Cleavage furrow forms to divide the cytoplasm
- Plant Cells: Cell plate forms to divide the cytoplasm
Terminology:
- Centrosome: A structure that organizes microtubules
- Aster: A radial array of microtubules emanating from the centrosome
- Microtubules: Hollow protein tubes that make up the spindle fibers
- Spindle Fibers: Microtubules that attach to chromosomes during mitosis
- Mitotic Spindle: The structure consisting of spindle fibers that helps separate chromosomes during mitosis
- Kinetochore: A protein complex that attaches spindle fibers to chromosomes
Cytokinesis: The division of the cytoplasm after mitosis
- Animal Cells: Cleavage furrow forms, pinching in the cell membrane to divide the cytoplasm
- Plant Cells: Cell plate forms, growing from the center outwards towards the cell walls to divide the cytoplasm

Asexual vs Sexual Life Cycles

Asexual Reproduction: A single parent produces genetically identical offspring, no genetic variation
- Types: Budding, fragmentation, fission
Sexual Reproduction: Two parents contribute genetic material to produce offspring, genetic variation
Animal Sexual Life Cycle: Diploid (2n) stage is dominant, haploid gametes (sperm and egg) fuse during fertilization to form a diploid zygote
Fungal Sexual Life Cycle: Haploid (n) stage is dominant, haploid spores fuse to form a diploid zygote
Plant Sexual Life Cycle: Alternation of generations, with both diploid (sporophyte) and haploid (gametophyte) stages

Meiosis

Basic Outcome: Four haploid (n) daughter cells, each genetically unique and half the number of chromosomes as the original parental cell
Meiosis I:
- Synapsis: Homologous chromosomes pair up side-by-side
- Crossing Over: Exchange of genetic material between homologous chromosomes, occurs during prophase I
- Independent Alignment: Homologous pairs align randomly at the metaphase plate, contributing to genetic variation
- Segregation of Homologs: Homologous chromosomes separate and move to opposite poles during anaphase I
Meiosis II: Similar to mitosis, but with haploid cells, sister chromatids separate during anaphase II
Terminology:
- Haploid (n): Cells with one set of chromosomes
- Diploid (2n): Cells with two sets of chromosomes
- Homologous Chromosomes: Chromosomes that carry the same genes in the same order
- Synapsis: Pairing of homologous chromosomes
- Crossing Over: Exchange of genetic material between homologous chromosomes
- Independent Alignment: Random alignment of homologous chromosome pairs at the metaphase plate

Mendelian Genetics

Terminology:
- Gene: A unit of heredity that occupies a specific locus on a chromosome
- Allele: Alternative forms of a gene
- Genotype: The genetic makeup of an individual
- Phenotype: The observable characteristics of an individual
- Heterozygote: An individual carrying two different alleles for a gene
- Homozygote: An individual carrying two identical alleles for a gene
- Dominant Allele: An allele that masks the expression of the recessive allele
- Recessive Allele: An allele whose expression is masked by the dominant allele
- True-Breeding Line: Individuals that produce offspring with the same phenotype when self-crossed
Three Important Crosses:
- AA x aa: Parental cross, produces all heterozygous offspring
- Aa x Aa: Dihybrid cross, produces offspring with a 1:2:1 genotypic ratio and a 3:1 phenotypic ratio
- Aa x aa: Test cross, used to determine the genotype of an unknown individual
Two-Gene Crosses: Involve two unlinked genes (located on different chromosomes), exhibit independent assortment
Mendel's Laws of Inheritance:
- Law of Segregation: Alleles at a gene segregate during meiosis
- Law of Independent Assortment: Alleles at different genes segregate independently of each other
Solving Genetic Problems:
- Punnett Squares: Diagrammatic method used to predict the genotypes and phenotypes of offspring
- Rules of Probability: Used to calculate the probabilities of specific outcomes
Mendelian Genetics and Hypothesis Testing:
- Developing Hypotheses: Formulate an educated guess about the pattern of inheritance
- Making Predictions: Predict the expected outcomes of genetic crosses
- Testing Predictions: Perform genetic crosses and compare the observed results to the predictions
Interpreting Genetic Data:
- Compare Observed to Expected: Determine if the observed data agrees with the predictions
- Support or Refute Hypotheses: Determine whether the data support the original hypothesis
Test Cross: Used to determine the genotype of an unknown individual, involves crossing the unknown individual with a homozygous recessive individual
Reciprocal Cross: Used to determine if the sex of the parent influences the pattern of inheritance, involves crossing the parents with the reciprocal genders
Variations on Single-Gene Crosses:
- Sex-Linked Traits: Genes located on sex chromosomes, often exhibit different inheritance patterns in males and females
- Multiple Alleles: More than two alleles for a gene exist in a population
- Dominance Hierarchies: Different alleles exhibit different levels of dominance
- Incomplete Dominance: Heterozygotes exhibit an intermediate phenotype
- Co-dominance: Both alleles are expressed simultaneously in the heterozygote

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Description

Test your knowledge on cell structure and the differences between prokaryotes and eukaryotes. This quiz covers key concepts such as the three domains of life, cell membranes, and organelles. Perfect for biology students wanting to enhance their understanding of cellular biology.