genetics exam 1

What is the study of genes and inheritance in living organisms?

Genetics

The specific genetic composition or DNA sequence of a cell is known as its _____.

Genotype

What term describes the outward, physical manifestation of an organism's traits?

Phenotype

The flow of genetic information in cells follows the sequence: DNA → _____ → protein.

RNA

What fundamental principle of molecular biology describes the flow of genetic information from DNA to RNA to protein?

The Central Dogma

Term: Gene

The fundamental physical and functional unit of heredity that carries information between generations.

A _____ is a segment of DNA composed of a transcribed region and a regulatory sequence.

Gene

What is the term for one of the different forms of a gene that can exist at a single locus?

Allele

What is the term for one of the different forms of a gene that can exist at a single locus?

Homozygous

What term describes an organism that contains different alleles for a specific gene?

Heterozygous

In a heterozygote, which trait is physically expressed or shown?

dominant

Who is considered the founder of modern genetics for discovering the laws of inheritance?

Gregor Mendel

Mendel proposed that factors controlling traits act like _____ rather than fluids.

particles

What were the 'particles' proposed by Mendel to control inheritance eventually named?

genes

Non-sex cells in multicellular organisms are referred to as _____ cells.

somatic

What is the general term for sex cells in multicellular organisms, such as eggs and sperm?

gametes

Which British scientist coined the term 'Genetics' in 1900?

William Bateson

Which scientist demonstrated that genes are located on chromosomes, establishing the chromosome theory?

Thomas Morgan

The _____ model proposed that genes encode enzymes that perform biochemical functions.

one-gene–one-enzyme

What genetic approach begins by identifying a mutant phenotype and works toward identifying the DNA sequence?

Forward genetics

What genetic approach begins with a known gene and alters it to observe the resulting physical effects?

Reverse genetics

Identify one primary characteristic that makes an organism suitable for use as a 'model organism' in genetics.

Fast cell growth and production of offspring.

Just before cell division, chromatin condenses to form discrete bodies called _____.

Chromosomes

What substance in the nucleus contains genomic DNA and gives it a granular appearance in non-dividing cells?

Chromatin

Approximately how many genes are humans estimated to have?

20,000 to 25,000

How many total chromosomes are found in a standard human somatic cell?

46 (or 23 pairs)

Which scientist discovered 'transformation' in 1927 while experimenting with S and R bacterial strains?

Frederick Griffith

Griffith concluded that a 'transforming principle' from the heat-killed _____ strain converted the live R strain.

S

Early geneticists initially believed _____ was the genetic material because of its complex structures.

Protein

According to Mendel's results, what determines the color of a pea plant?

An inherited gene

In a Y/y pea plant, which allele is recessive?

The y (green) allele

The principle of _____ states that the members of a gene pair separate equally into eggs and sperm.

Equal segregation

How many alleles of a specific gene does a single gamete contain?

One

At fertilization, gametes fuse _____ regardless of the alleles they carry.

Randomly

Which phenotypic ratio is characteristic of single-gene inheritance in a F2​ generation?

3:1

Which genotypic ratio is diagnostic of single-gene inheritance in a F2​ generation?

1:2:1

Genome

The collective term for all the different DNA molecules within a cell or organism.

Why did early geneticists doubt DNA was the hereditary material based on nucleotide ratios?

They incorrectly believed the four nucleotides were always in a 1:1:1:1 ratio.

Identify the process where DNA is used to synthesize complementary RNA.

Transcription

Identify the process where RNA is used as a template to build a polypeptide chain on a ribosome.

Translation

A DNA segment that makes transcription possible is called a _____ sequence.

Regulatory

What two simple questions define the beginning of the study of Genetics?

Why do offspring resemble parents and why are there differences between them?

Mendel's experimental model involved the cross-pollination of different varieties of the _____ plant.

Pea

What specific flower colors did Mendel use in his pioneering genetic cross experiment?

purple and white

The term _____ refers to the physical position of a gene on a chromosome.

Locus

Which scientist's laboratory worked to identify the specific 'transforming factor' after Griffith's experiment?

Oswald Avery

Which two scientists performed experiments using radioactivity in bacteria to confirm DNA as the genetic material?

Alfred Hershey and Martha Chase

What is the primary role of histone proteins in the cell?

They are the core around which DNA winds to form nucleosomes.

The 'beads on a string' structure in the nucleus consists of DNA wound on _____.

Nucleosomes

In Mendel's crosses, what was the phenotypic ratio of offspring when crossing an F1​ yellow seed plant (Y/y) with a green seed plant (y/y)?

1:1

How does the 'one-gene-one-enzyme' model explain the link between genotype and phenotype?

Genes provide the instructions to create enzymes that carry out specific biochemical functions.

Somatic cells in humans contain _____ pairs of chromosomes.

23

What Greek words form the root of the term 'chromosome'?

Colored bodies

Geneticists who study how traits are passed from parents to offspring are focused on _____ genetics.

Transmission

Forward genetics begins with a _____ phenotype.

Mutant

Reverse genetics uses techniques such as gene _____, knockout, or over-expression.

Mutation

In the context of single-gene inheritance, equal segregation occurs in a _____ organism.

Heterozygous

What occurs at the molecular level when a polypeptide chain folds?

It forms the native structure of a functional protein (like hexokinase).

Identify the two types of DNA molecules that can exist within a eukaryotic cell.

Nuclear DNA and Mitochondrial DNA.

What chemical energy molecule is required for hexokinase to convert glucose to glucose 6-phosphate?

ATP