Introduction to Genetics Terminology

Questions and Answers

What is the study of heredity called?

Evolution

Genetics (correct)

Biology

Zoology

What occurs during fertilization?

Sperm enters egg

True-breeding genotypes are always heterozygous.

False

What is a trait?

A characteristic passed on to offspring through genes Signup and view all the answers

What defines a hybrid organism?

An organism that has two different alleles for a trait Signup and view all the answers

What is an allele?

An alternative form of a gene Signup and view all the answers

What is the Law of Segregation?

Mendel's law stating homologous chromosomes separate in meiosis Signup and view all the answers

Define a gamete.

A haploid cell such as an egg or sperm Signup and view all the answers

What is the probability in genetics?

The possibility of a child having a certain trait Signup and view all the answers

What is a Punnett square?

A chart showing possible combinations of alleles from a genetic cross Signup and view all the answers

What does homozygous mean?

Having two identical alleles Signup and view all the answers

What does heterozygous mean?

Having two different alleles Signup and view all the answers

What is a phenotype?

The physical appearance of an organism Signup and view all the answers

Define genotype.

The genetic makeup of an organism Signup and view all the answers

What does the Law of Independent Assortment state?

Each allele pair segregates independently during gamete formation Signup and view all the answers

Incomplete dominance means one allele is completely dominant over the other.

False Signup and view all the answers

Codominance occurs when both alleles are expressed equally.

True Signup and view all the answers

What are multiple alleles?

Three or more alleles of the same gene Signup and view all the answers

What are polygenic traits?

Traits controlled by two or more genes Signup and view all the answers

Define homologous chromosomes.

Chromosomes with the same information Signup and view all the answers

What does diploid mean?

Two sets of chromosomes Signup and view all the answers

What does haploid mean?

One complete set of chromosomes Signup and view all the answers

What is meiosis?

Process of one cell becoming four haploid cells Signup and view all the answers

Define a tetrad.

Each pair of homologous chromosomes Signup and view all the answers

What is crossing-over?

Process where chromosomes share DNA with each other Signup and view all the answers

What is a gene map?

Diagram showing the relative locations of each known gene on a chromosome Signup and view all the answers

What is selective breeding?

Breeding certain organisms to obtain desired characteristics Signup and view all the answers

What is hybridization?

Breeding two different types of characteristics Signup and view all the answers

What is inbreeding?

Selective breeding method crossing individuals with similar alleles Signup and view all the answers

Define genetic engineering.

Process of altering the DNA code of living organisms Signup and view all the answers

What is a clone?

The copying of DNA Signup and view all the answers

What is a karyotype?

A display of chromosome pairs arranged by size and shape Signup and view all the answers

What are sex chromosomes?

Chromosomes that determine gender Signup and view all the answers

Define an autosome.

Chromosomes that are not sex chromosomes Signup and view all the answers

What is a pedigree?

Diagram showing the occurrence of a genetic trait in several generations Signup and view all the answers

What is a sex-linked gene?

Gene located on the X or Y chromosome Signup and view all the answers

What is nondisjunction?

Error in meiosis when homologous chromosomes fail to separate Signup and view all the answers

What is gel electrophoresis?

Procedure used to separate and analyze DNA fragments Signup and view all the answers

What is a restriction enzyme?

Enzyme that cuts DNA at a specific sequence of nucleotides Signup and view all the answers

What is recombinant DNA?

DNA produced by combining DNA from different sources Signup and view all the answers

What is a DNA fingerprint?

Technique for identifying individuals based on DNA base-pair patterns Signup and view all the answers

Study Notes

Genetics Terminology

Genetics is the scientific study of heredity, focusing on genes and their roles in inheritance.
Fertilization is the biological process where sperm enters the egg, crucial for mammalian reproduction.
True-breeding organisms are homozygous for a trait, consistently producing offspring with identical phenotypes.
A trait is a specific characteristic passed from parents to offspring through genes, such as freckles.

Genetic Variations

A hybrid organism possesses two different alleles for a given trait, leading to diverse characteristics like in grapefruits.
Alleles are alternative forms of a gene that contribute to variations in traits; they are found in non-sex-linked genes.
The Law of Segregation, proposed by Mendel, describes how homologous chromosome pairs separate during meiosis, allowing for genetic diversity in gametes.

Gametes and Probability

Gametes are haploid cells, like eggs and sperm, essential for sexual reproduction and fertilization.
Probability in genetics refers to the likelihood of an offspring inheriting a specific trait, often represented in pedigree projects.
A Punnett square is a tool that visually represents the possible allele combinations from a genetic cross.

Genotypic and Phenotypic Concepts

Homozygous individuals have identical alleles, while heterozygous individuals carry different alleles for the same gene.
Phenotype refers to the observable physical traits of an organism, while genotype indicates its genetic makeup.

Mendelian Laws

The Law of Independent Assortment states allele pairs separate independently during gamete formation, contributing to genetic variation.
Incomplete dominance occurs when neither parental allele is completely dominant, resulting in a blended phenotype.
Codominance arises when both alleles are expressed equally, exemplified by certain patterns in co-captain traits.

Genetic Complexity

Multiple alleles refer to the presence of three or more alleles for a single gene, increasing trait variability.
Polygenic traits are influenced by multiple genes, encompassing characteristics like human eye and hair color.
Homologous chromosomes have identical genetic information, crucial for accurate cell division.

Chromosomes and Cell Division

Diploid organisms possess two sets of chromosomes, such as humans with 46 chromosomes, while haploid organisms have one set, like gametes with 23 chromosomes.
Meiosis is the process where one cell divides to form four unique haploid cells, crucial for sexual reproduction.
Tetrads consist of paired homologous chromosomes during meiosis, facilitating genetic recombination through crossing-over.

Genetic Technologies

Crossing-over is the exchange of DNA between homologous chromosomes during meiosis, increasing genetic diversity.
A gene map displays the locations of genes on chromosomes, aiding in genetic research and mapping efforts.
Genetic engineering involves altering an organism's DNA code to achieve desired traits or functions.

Cloning and Identification

Cloning refers to creating copies of DNA or entire organisms, particularly in agricultural and medical research.
A karyotype is a diagram showing chromosome pairs arranged by size and shape, used to identify chromosomal abnormalities.
Sex chromosomes determine an organism's gender, while autosomes are all other chromosomes not involved in sex determination.

Genetic Disorders and Techniques

A pedigree is a family tree that illustrates the inheritance of a genetic trait across several generations.
Sex-linked genes are found on sex chromosomes, influencing traits such as color blindness.
Nondisjunction refers to errors in meiosis where chromosomes fail to separate, leading to disorders like Down syndrome.

Molecular Techniques

Gel electrophoresis separates and analyzes DNA fragments, a key technique for forensic and genetic studies.
Restriction enzymes cut DNA at specific sequences, critical for genetic engineering and DNA analysis.
Recombinant DNA technology combines DNA from different organisms, allowing for advances in biotechnology.
DNA fingerprinting is a method for identifying individuals based on their unique base-pair patterns, widely used in forensic science.

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Description

This quiz covers fundamental concepts in genetics, including key terms like heredity, fertilization, and genetic variations. Explore the roles of alleles and the Law of Segregation in understanding biological inheritance and diversity. Test your knowledge of these essential principles that form the basis of genetic science.