Biology Chapter on Genes and Chromosomes

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Questions and Answers

Match the following inheritance patterns with their characteristics:

Autosomal recessive = Equal number of affected males and females, can skip generations X-linked dominant = More affected females than males, trait passes from affected father to all daughters X-linked recessive = More males affected, all sons of affected mothers will be affected Autosomal dominant = Affected individuals must have an affected parent, trait does not skip generations

Match the genetic conditions with their inheritance patterns:

Albinism = Autosomal recessive Incontinentia pigmenti = X-linked dominant Color blindness (red-green) = X-linked recessive Thalassemia = Autosomal recessive

Match the following traits to their descriptions:

Favism = Red blood cells destroyed upon contact with agent Wilson's disease = Accumulates copper in tissues, autosomal recessive trait Vitamin D resistant rickets = X-linked dominant condition affecting calcium metabolism Osteogenesis imperfecta = Autosomal dominant condition leading to brittle bones

Match the genetic relationships with their potential outcomes:

Affected father and unaffected mother = All daughters will inherit the trait Unaffected parents = Can have affected child if both are carriers Affected mother and unaffected father = Sons may or may not inherit the trait Affected sibling pair = Can produce unaffected offspring if both are carriers Signup and view all the answers

Match the following terms with their definitions:

Carrier = Individual with one recessive allele but does not express the phenotype Phenotype = Observable characteristics determined by genetics Genotype = Genetic makeup of an individual Pedigree = Diagram showing the inheritance of a trait across generations Signup and view all the answers

Match the following inheritance examples with their patterns:

Tay-Sachs disease = Autosomal recessive trait Red hair color = Autosomal recessive trait Color blindness = X-linked recessive trait Vitamin D resistant rickets = X-linked dominant trait Signup and view all the answers

Match these key genetic principles with their descriptions:

Law of Segregation = Alleles separate during gamete formation Law of Independent Assortment = Different genes independently separate from one another when reproductive cells develop Penetrance = The proportion of individuals with a genotype that express the associated phenotype Expressivity = The degree to which a genotype is expressed in the phenotype Signup and view all the answers

Match the following genetic traits with their corresponding examples:

Autosomal dominant = Achondroplasia X-linked recessive = Duchenne muscular dystrophy X-linked dominant = Fragile X syndrome Autosomal recessive = Cystic fibrosis Signup and view all the answers

Match the following cloning techniques with their descriptions:

Therapeutic cloning = Produces embryonic stem cells for tissue replacement Adult cloning = Uses cells from fully developed adult tissue Economic cloning = Focuses on cost-effective resource development Biopiracy = Utilization of traditional knowledge without permission Signup and view all the answers

Match the symbiotic relationships with their definitions:

Mutualism = Both organisms benefit from the relationship Commensalism = One organism benefits while the other is unaffected Parasitism = One organism benefits at the expense of the other Predation = One organism hunts and eats another organism Signup and view all the answers

Match the examples to their type of symbiotic relationship:

Bird and buffalo = Mutualism Clownfish and anemone = Commensalism Remora fish and shark = Commensalism Pygmy possum and flowers = Mutualism Signup and view all the answers

Match the autosomal dominant conditions with their descriptions:

Huntington's disease = Condition that appears in nearly every generation Dwarfism = Expressed with one or more copies of the dominant allele Alzheimer's disease = Inherited condition that tends to affect both genders equally Familial breast cancer = Condition linked to genetic predisposition in families Signup and view all the answers

Match the autosomal recessive pattern with their characteristics:

Expressed when = Two copies of recessive allele are present Affected individuals = Can be born to non-affected parents Gender distribution = Equal number of sexes affected Generation appearance = May skip generations in lineage Signup and view all the answers

Match the elements of Aboriginal and Torres Strait Islander practices with their impacts:

Sustainable fishing = Prevents overfishing and promotes population recovery Cultural connection to land = Strengthens spiritual relationships with the environment Indigenous knowledge study = Helps in understanding adaptations for survival Population management = Ensures density and distribution are not negatively impacted Signup and view all the answers

Match the following terms with their meanings in genetics:

Dominant allele = Allele that masks the effect of the recessive allele Recessive allele = Allele that only expresses if two copies are present Pedigree = Diagram tracking inheritance of traits in families Genotype = Genetic constitution of an individual Signup and view all the answers

Match the types of symbiotic relationships with their key characteristics:

Mutualism = Both species benefit Commensalism = One species benefits without affecting the other Parasitism = One species benefits and the other is harmed Competition = Two species compete for the same resources Signup and view all the answers

Match the following stages of meiosis with their descriptions:

Metaphase 1 = Homologous chromosomes line up in the center. Anaphase 1 = Whole chromosomes pulled to opposite ends. Telophase 1 = Nuclear membrane reforms and cell divides. Metaphase 2 = Pairs of chromatids line up along the equator. Signup and view all the answers

Match the following blood types with their antigens:

Blood Type A = A antigen on cell surface. Blood Type B = B antigen on cell surface. Blood Type AB = Both A and B antigens present. Blood Type O = No antigens present. Signup and view all the answers

Match the following terms with their examples:

Co-dominance = Both alleles are expressed in the phenotype. Homo dominant = Genotype AA. Homo recessive = Genotype aa. Carrier = Has genotype Aa. Signup and view all the answers

Match the following stages of meiosis with their outcomes:

Anaphase 2 = Chromatids pulled apart to opposite ends. Telophase 2 = Four haploid cells produced. Prophase 2 = Nuclear membrane breaks down. Cytokinesis = Cell divides after telophase. Signup and view all the answers

Match the following characters with their meanings in genetics:

Genotype = Set of genes in an organism's DNA. Phenotype = Visible traits observed in an organism. Allele = One version of a gene. Trait = Characteristic controlled by genotype. Signup and view all the answers

Match the following genotype combinations with their classifications:

AA = Homozygous dominant. Aa = Heterozygous. aa = Homozygous recessive. IAIB = Co-dominant alleles. Signup and view all the answers

Match the following statements with their implications in genetic inheritance:

Diploid = Organism with two complete sets of chromosomes. Haploid = Organism with one complete set of chromosomes. Cytokinesis occurs = Final step in cell division. Chromosome number doubles = Result of anaphase 1 in meiosis. Signup and view all the answers

Study Notes

Genes

A gene is an inherited characteristic made of DNA.
It controls structures, physiology and behaviour.
A gene codes for a protein, a polymer made from amino acids (monomers).
Three bases form a codon, and when read, produce an amino acid.
A chain of amino acids forms a protein.
An allele is a variation of a gene; different forms of the same gene.
The genome is the total set of genetic DNA (base pairs) carried by an individual in a body cell.
Epigenetics is the study of mutations to gene expression that do not involve altering DNA sequences.

Chromosomes

DNA coils in eukaryotic cells to form chromosomes.
Body (somatic) cells have 46 chromosomes (diploid- 2n), with two sets of linear chromosomes.
Sex cells have 23 chromosomes (haploid- n), with one set of linear chromosomes.
Chromosome number and size vary in different species, and even within the same species.
Autosomes are chromosomes 1-22 (22 pairs or 44 overall).
Sex chromosomes are pair 23 (XX for females, XY for males).
There are 46 homologous chromosomes, arranged into 23 pairs.

Meiosis

Meiosis is the splitting of a cell to produce four cells with half the number of chromosomes as the original.
Body cells are diploid (2n=46).
Sex cells are haploid (n=23).
Meiosis produces gametes (haploid cells) with half the genetic material of the original cell.
Fertilization of sperm (n) and ova (n) produces a zygote (2n).
Meiosis produces random combinations of homologous pairs via independent assortment.
It provides variation and occurs during metaphase 1.
Meiosis allows exchange of chromatid segments between chromosomes, known as crossing over, which occurs during prophase 1 and provides variation.

Meiosis Stages

Interphase: Chromosomes duplicate.
Prophase 1: Chromosomes become visible, double-stranded, crossing over occurs, and the nuclear envelope breaks down. Homologous chromosomes pair up (synapsis) and swap sections (chiasmata).
Metaphase 1: Homologous chromosomes line up in the center of the cell.
Anaphase 1: Whole chromosomes are pulled to the opposite ends of the cell by spindle fibers.
Telophase 1 & Cytokinesis: Chromosomes are at opposite ends, the nuclear membrane reforms, and the cell divides to create two daughter cells.
Prophase 2: Nuclear membrane breaks down, and chromosomes become visible.
Metaphase 2: Chromosomes line up along the equator of the cell.
Anaphase 2: Chromatids are pulled apart and move to opposite ends of the cell.
Telophase 2 & Cytokinesis: Nuclear envelope forms around chromosomes/cells and cytoplasm divides, resulting in 4 haploid cells.

Genotypes & Phenotypes

Genotype is the set of genes in DNA controlling a trait.
Dominant traits are expressed by individuals (AA or Aa).
Recessive traits are masked by dominant traits (aa).
Homozygous means 2 identical alleles (AA or aa).
Heterozygous means 2 different alleles (Aa). Heterozygotes are carriers for recessive alleles.
Phenotype is the visible trait observable from an organism's structure or function, determined by genotype and environment. Examples include eye color, height and fruit color.

Co-dominance

Co-dominance occurs when both alleles are expressed in the phenotype. Neither allele is recessive.
Blood type is an autosomal trait.
Blood type A has A antigen on cell surface (IA).
Blood type B has B antigen on cell surface (IB).
Blood type AB has both A and B antigens (IA and IB), which is co-dominant.
Blood type O has neither antigen (ii).

Asexual Reproduction

Asexual reproduction is where one parent organism produces offspring genetically identical to it.
No gametes are involved.
Methods include budding, where a "bud" breaks away from the parent and develops into a new organism; fragmentation, where the parent organism divides into separate parts, each capable of developing into a new organism; and vegetative propagation in plants, where new plants are formed from parts of the parent plant, such as cuttings.

Sexual Reproduction

Sexual reproduction involves the fusion of two haploid gametes (ova and sperm) to form a genetically unique zygote.
It provides genetic variation in a population, allowing organisms to adapt to changes in the environment and develop resistance to diseases.
Disadvantages include more time, energy and resources, risk of spreading diseases and loss of embryo.

Cloning

Cloning involves getting DNA from one organism and creating identical copies of it.
Copied material/organism is called a clone.
Reproductive cloning produces copies of whole animals.
Therapeutic cloning produces embryonic stem cells for experiments to replace injured/damaged tissues.

Relationships in Ecosystems

Symbiosis is the relationship between two different species, where they can benefit, not be affected, or harmed.
Mutualism is a relationship where both organisms benefit (e.g., bird picking fleas off a buffalo).
Commensalism is a relationship where one organism benefits and the other isn't affected (e.g., clownfish and sea anemone).

Aboriginal & Torres Strait Islander Knowledge

Aboriginal & Torres Strait Islander people have a strong spiritual connection to land.
They study the adaptations of indigenous animals and how they reproduce to ensure survival.
Community practices ensure that the density and distribution of populations aren't negatively impacted.
Biopiracy occurs when traditional indigenous knowledge is used to develop resources without permission.

Autosomal Dominant Pattern

Expressed when one or more copies of a dominant allele are present.
Both males and females can have it.
All affected individuals have at least one affected parent.
Appears in nearly every generation and equally affects males and females. Example: Huntington’s disease, dwarfism, high cholesterol.

Autosomal Recessive Pattern

Expressed when two copies of a recessive allele are present.
Both males and females can have it.
Two unaffected parents can have an affected child.
Equally affects males and females example: Albinism, Thalassaemia, Tay-Sachs disease .

X-linked Dominant Pattern

Dominant gene carried on the X chromosome and one copy is needed to express the phenotype.
More affected females than males.
Male with trait passes it to all his daughters.
Female with trait can pass it to both daughters and sons.

X-linked Recessive Pattern

Trait carried on the X chromosome where one copy is required for males and two for females to express the phenotype.
More males than females show the trait.
All sons of a female with trait will be affected.
All daughters of a male with trait will be carriers.

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Description

This quiz covers the fundamental concepts of genes and chromosomes, including their structure and function. It explores topics such as DNA, allele variation, and the distinction between somatic and sex cells. Test your understanding of these essential genetic principles.