DNA and Chromosomes in eukaryotic and prokaryotic cells

• What is the definition of a gene in molecular biology?

  A short section of DNA
• A gene codes for a polypeptide and a functional RNA
• A gene directly codes for a functional protein.

  False
• What is the primary structure of a protein?

  A polypeptide chain
• The Golgi apparatus processes proteins by folding and adding chemical modifications
• What is the definition of a locus in genetics?

  The location of a gene
• All humans have the same genes but different alleles.
• What is an allele?

  A different form of a gene
• Different alleles result in slightly different proteins
• Match the genetic term with its description:

  Gene ↔️ Codes for a polypeptide

  Locus ↔️ The location of a gene

  Allele ↔️ A different form of a gene
• Chromosomes are only visible during cell division.

  False
• How many chromosomes are present in a human somatic cell nucleus?

  46
• During cell division, replicated chromosomes are held together by a centromere
• What is a homologous pair of chromosomes?

  A pair with identical genes
• Homologous chromosomes may have different alleles for the same gene.
• What is a human karyotype?

  An image of all chromosomes
• The 23rd pair of chromosomes in humans determines biological sex
• Which chromosomes are present in a male human?

  X and Y
• Histone proteins help prevent DNA from becoming tangled.
• What is a nucleosome?

  DNA wrapped around a histone
• In prokaryotic cells, DNA is circular and not bound to histones
• Prokaryotic DNA is located within the nucleus.

  False
• Which two organelles in eukaryotic cells contain their own DNA?

  Mitochondria and chloroplasts
• The DNA in mitochondria and chloroplasts is similar to prokaryotic DNA
• The DNA in mitochondria is linear in shape.

  False
• Steps in DNA compaction in eukaryotic cells

  1️⃣ DNA double helix coils around histones

  2️⃣ Nucleosomes form

  3️⃣ Chromosomes are created