Genetics and Cell Biology: DNA, Chromosomes, and Cell Types

What is a chromosome?

A DNA molecule with protein found in the nucleus that carries genetic information.

What are nucleotides?

The building blocks of DNA and RNA, made of phosphate group, sugar, and nitrogenous base.

What are the bases in DNA?

Adenine (A), Cytosine (C), Guanine (G), Thymine (T).

What are the bases in RNA?

Adenine (A), Cytosine (C), Guanine (G), Uracil (U).

What sugar is found in DNA?

Deoxyribose.

What sugar is found in RNA?

Ribose.

How do bases pair in DNA?

A‑T and C‑G via hydrogen bonds.

How do bases pair in RNA?

A‑U and C‑G.

What is the difference between prokaryotic and eukaryotic cells?

Prokaryotes lack a nucleus/organelles; eukaryotes have a nucleus and organelles.

What type of chromosome do prokaryotes have?

A single circular chromosome attached to the membrane.

What type of chromosomes do eukaryotes have?

Linear chromosomes inside the nucleus, wrapped around histone proteins.

What is DNA?

Deoxyribonucleic acid, a double helix that encodes genetic information and guides protein production.

What is RNA?

Ribonucleic acid, a single strand that transfers genetic information from nucleus to cytoplasm.

What are autosomes?

Non‑sex chromosomes; humans have 44 autosomes (22 pairs).

What are allosomes?

Sex chromosomes (X and Y).

How many chromosomes do humans have?

46 total (23 pairs).

What is a karyotype?

The photographic arrangement of a complete set of chromosomes in homologous pairs.

Which pair of chromosomes determines sex?

The 23rd pair (XX = female, XY = male).

What is a gene?

A region of DNA that encodes a function, such as a protein.

How many genes can a human chromosome contain?

Thousands, up to 500 million base pairs.

What is heredity based on?

DNA sequences called genotypes.

What is the difference between dominant and recessive alleles?

Dominant allele (D) masks recessive allele (d); genotypes can be DD, Dd, or dd.

What is a genetic mutation?

An abnormal change in DNA sequence that can produce abnormal proteins or no protein.

Chromosome

A cell that contains protein and one DNA molecule and that is found in the nucleus of the cell

Nucleotides

The basic cells that serve as the building blocks of both RNA and DNA.

DNA

Deoxyribonucleic acid, a nucleic acid, long molecule and macromolecule

RNA

Ribonucleic acid, a nucleic acid, long molecule and macromolecule

Gene

The part of the DNA that encodes information

Autosome

A sex chromosome

Allosome

Also referred to as an allosomal chromosome or a body chromosome is a non sex chromosomes despite the fact that allosomes do play a role in sexual determination for males and females.

Prokaryotes

A types of cell that does not have organelles or a nucleus

Eukaryotes

The type of cell that has a nucleus containing genetic material and organelles