3.4.1 DNA , Genes and chromosomes ( 3.4 Genetic information , variation and relatoonships between organisms) Flashcards
What are the similarities between DNA in eukaryotic and prokaryotic cells?
Nucleotide structure is identical - deoxyribose attached to phosphate and a base. Adjacent nucleotides joined by phosphodiester bonds, complementary bases joined by hydrogen bonds. DNA in mitochondria / chloroplasts have similar structure to DNA in prokaryotes.
Short, circular, not associated with proteins.
What are the differences between DNA in eukaryotic and prokaryotic cells?
Eukaryotic DNA is longer, linear, and associated with histone proteins. Prokaryotic DNA is circular and not associated with proteins. Eukaryotic DNA contains introns, while prokaryotic DNA does not.
What is a chromosome?
Long, linear DNA + its associated histone proteins, located in the nucleus of eukaryotic cells.
What is a gene?
A sequence of DNA (nucleotide) bases that codes for the amino acid sequence of a polypeptide or a functional RNA (e.g., ribosomal RNA or tRNA).
What is a locus?
Fixed position a gene occupies on a particular DNA molecule.
What is the nature of the genetic code?
Triplet code: A sequence of 3 DNA bases, called a triplet, codes for a specific amino acid. Universal: The same base triplets code for the same amino acids in all organisms. Non-overlapping: Each base is part of only one triplet, so each triplet is read as a discrete unit. Degenerate: An amino acid can be coded for by more than one base triplet.
What are the similarities between DNA in eukaryotic and prokaryotic cells?
Nucleotide structure is identical - deoxyribose attached to phosphate and a base. Adjacent nucleotides joined by phosphodiester bonds, complementary bases joined by hydrogen bonds. DNA in mitochondria / chloroplasts have similar structure to DNA in prokaryotes.
Short, circular, not associated with proteins.
What are the differences between DNA in eukaryotic and prokaryotic cells?
Eukaryotic DNA is longer, linear, and associated with histone proteins. Prokaryotic DNA is circular and not associated with proteins. Eukaryotic DNA contains introns, while prokaryotic DNA does not.
What is a chromosome?
Long, linear DNA + its associated histone proteins, located in the nucleus of eukaryotic cells.
What is a gene?
A sequence of DNA (nucleotide) bases that codes for the amino acid sequence of a polypeptide or a functional RNA (e.g., ribosomal RNA or tRNA).
What is a locus?
Fixed position a gene occupies on a particular DNA molecule.
What is the nature of the genetic code?
Triplet code: A sequence of 3 DNA bases, called a triplet, codes for a specific amino acid.
Universal: The same base triplets code for the same amino acids in all organisms.
Non-overlapping: Each base is part of only one triplet, so each triplet is read as a discrete unit.
Degenerate: An amino acid can be coded for by more than one base triplet.
What are non-coding base sequences?
DNA that does not code for amino acid sequences or polypeptides.
Where are non-coding base sequences found?
- Between genes (e.g., non-coding multiple repeats)
- Within genes (introns)
In eukaryotes, much of the nuclear DNA does not code for polypeptides.
What is an exon?
Base sequence of a gene coding for amino acid sequences in a polypeptide.
