Name:_Answer Key_______________________________ Date:__________________ Block:___________________
Unit 6 Study Guide: DNA Structure
Use your notes to define the following terms or scientists. DO NOT forget your illustrations.
Word and Definition
Illustration/Contribution
DNA:
Deoxyribonucleic acid is a molecule that encodes the
genetic instructions used in the development and
functioning of all known living organisms and many
viruses.
Draw and label:
Nitrogen Base:
Nitrogenous bases are one of the fundamental
components of nucleic acids, such as DNA
Draw and Label:
Codon:
A sequence of three nucleotides that together form a
unit of genetic code in a DNA molecule.
Draw:
Nucleotide:
Draw and Label:
A nucleotide is a molecule made up of a
nitrogen base, a five-carbon sugar, and at least
one phosphate group. Nucleotides make up the
basic units of DNA molecules.
Double Helix:
A term used to describe the structure of DNA. The
shape is similar to that of a spiral staircase.
Draw:
Chargaff’s Rule:
In the base composition of DNA, the quantity of adenine
equaled the quantity of thymine and the quantity of
guanine equaled the quantity of cytosine.
Draw and label:
Chromosome:
A structure of nucleic acids and protein found in the
nucleus of most living cells, carrying genetic
information in the form of genes.
Draw
Gene:
A hereditary unit consisting of a sequence of DNA that
occupies a specific location on a chromosome and
determines a particular characteristic in an organism.
Draw:
Rosalind Franklin:
Contribution
British x-ray crystallographer; Franklin's x-ray photograph
depicting the double-helix shape of DNA gave Watson and
Crick the essential experimental evidence they needed to
determine DNA's structure.
Franklin's x-ray photograph depicting the double-helix
shape of DNA gave Watson and Crick the essential
experimental evidence they needed to determine DNA's
structure.
Watson and Crick:
Contribution
In 1962 James Watson & Francis Crick jointly received
the Nobel Prize for their 1953 determination of the
structure of deoxyribonucleic acid (DNA).
A new understanding of heredity and hereditary
disease was possible once it was determined that
DNA consists of two chains twisted around each
other, or double helixes, of alternating phosphate
and sugar groups, and that the two chains are held
together by hydrogen bonds between pairs of
organic bases
1. If TTGGCTA is a strand of DNA, what would its complementary strands look like?
AACCGAT
2. In DNA, what are the sides of the ladder and the steps of the ladder made up of?
Sides – phosphate and sugar
Rungs (steps) – nitrogen bases
3. Describe the relationship between DNA, chromosomes, and genes. What makes up what? Describe in words and
illustrate below:
Chromosomes are composed of long
strands of material made of DNA and
proteins. Chromosomes are made
of tightly coiled strands of DNA. A gene
is a particular segment of the chromosome
that codes for an inherited trait.