Chapter 7 – DNA Structure and Gene Function

Flashcards covering key terms and definitions related to DNA structure, gene function, and various biological processes.

DNA

Deoxyribonucleic Acid, the molecule that carries genetic information.

Nucleotide

The building block of DNA, consisting of deoxyribose, a phosphate group, and a nitrogenous base.

Double Helix

The structure of DNA, resembling a twisted ladder.

Nitrogenous Bases

Four chemical bases in DNA: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).

Rosalind Franklin

Scientist who contributed critical data to the discovery of DNA's structure.

RNA

Ribonucleic Acid, which carries genetic messages from DNA and helps make proteins.

Mutagen

A factor that causes mutations, such as UV light or chemicals.

Apoptosis

Programmed cell death.

Meiosis

Process that produces haploid gametes for sexual reproduction.

Cancer

A condition characterized by uncontrolled cell division due to mutations.

Gametes

Haploid cells (sperm and egg) involved in sexual reproduction.

Zygote

A fertilized egg formed by the union of sperm and egg.

Chromosome

A structure that carries genetic information, composed of DNA.

Karyotype

A size-ordered chart of an individual's chromosomes.

Homozygous

An organism with two identical alleles for a given trait.

Heterozygous

An organism with two different alleles for a given trait.

Dominant Allele

An allele that is expressed in the phenotype regardless of its partner allele.

Recessive Allele

An allele that is masked by the presence of a dominant allele.

Phenotype

The physical appearance or observable characteristics of an organism.

Genotype

The genetic makeup of an organism.

Punnett Square

A diagram used to predict the genotypes of a genetic cross.

What is the structure of DNA?

DNA (deoxyribonucleic acid) has a double helix structure, consisting of two strands of nucleotides twisted together, with complementary bases pairing between them (adenine with thymine, and cytosine with guanine).

What is the function of genes in DNA?

Genes are segments of DNA that contain the instructions for making proteins, which perform various functions in the body and determine traits.

Describe the process of DNA replication.

DNA replication is the semi-conservative process where the DNA molecule unwinds and each original strand serves as a template for the creation of a new complementary strand, resulting in two identical DNA molecules.

What are the key steps of DNA replication?

The key steps of DNA replication include:

• Initiation: DNA unwinding by helicase.
• Elongation: DNA polymerase synthesizing new strands.
• Termination: Completion of the complementary strands and re-forming the double helix.

What is mitosis?

Mitosis is the process of cell division that results in two genetically identical daughter cells, allowing for growth and repair in an organism.

What is meiosis?

Meiosis is a specialized form of cell division that produces four non-identical gametes (sperm or eggs) with half the number of chromosomes, which is essential for sexual reproduction.