DNA and RNA

1
DNA and RNA
2
DNA

• Deoxyribonucleic acid (DNA)- contains information
  on how to make proteins. Proteins are the
  building blocks of life.
• DNA is made up of a sugar (deoxyribose), a
  phosphate group and four nitrogen bases.
• The 4 nitrogen bases are
• Guanine (G), Cytosine (C), Thymine (T) and
  Adenine (A).

3

• In DNA, Adenine and Thymine make up a base pair,
  while Guanine and Cytosine make up the other base
  pair.
• Together a phosphate group, a sugar and one
  nitrogen base make up a NUCLEOTIDE.

4
Structure

• DNA is a double stranded structure referred to as
  a double helix or twisted ladder.
• DNA always turns to the right.
• Nitrogen base pairs are held together by Hydrogen
  bonds- AT, GC

5
Where is DNA found?

• DNA is found in the nucleus of cells, and can be
  referred to as chromatin.

6
RNA

• Like DNA, Ribonucleic acid is also made up a
  sugar, phosphate group and nitrogen bases. But
  there are some major differences--
• The sugar in RNA, is Ribose.
• the nitrogen bases consist of Uracil (U),
  Adenine, Guanine (G) and Cytosine (C).
• Uracil and Adenine Base Pair
• Guanine and Cytosine Base Pair

7
                 

• A nucleotide consist of a sugar, phosphate group
  and one nitrogen base.
• Like DNA, the backbone of RNA is composed of
  phosphates and sugars.
• RNA is single stranded.

8
Time for practice!

• Practice Questions

9
Question from Fall 2005 TAKS Test

• 28. Thymine-guanine-thymine-cytosine
• describes
• Nucleotides within an RNA strand
• A sequence of bases within the DNA section
• Points of DNA separation during protein synthesis
• J. tRNA codons for specific amino acids

10
Answer!!!

• The answer is G!!!!
• Thymine, adenine, Guanine and Cytosine are all
  nitrogen bases that can be found in a DNA
  sequence.

11
Question from July 2004

• All of the following are found in a DNA molecule
  except-
• carbon dioxide
• deoxyribose
• nitrogen
• phosphate

12
Answer!!!

• The answer is A!!!
• A DNA molecule is made up of 3 main parts. The
  Phosphate group, a nitrogen base and a sugar
  (deoxyribose). Together these 3 parts are called
  a nucleotide.

13
Question from 2003 TAKS test

• If the template of a strand of DNA is AGATGCATC,
  the complementary strand will be-
• TCTACGTAG
• CTACGTAGA
• AGATGCATC
• J. AGACGTCTA

14
Answer!!!

• The answer is F!!!
• Adenine and Thymine pair up together
• Guanine and Cytosine pair up together

15
Question from April 2006

• In all plant and animal cells, the nucleus
  contains long molecules of DNA. Which of the
  following best describes the function of DNA?
• DNA provides the shape and structure of the
  nucleus.
• DNA packages materials for transport through the
  nucleus.
• DNA carries materials into and out of the
  nucleus.
• J. DNA contains the blueprint for producing
  the whole organism.

16
Answer!!!

• The answer is J!!!
• DNA can be thought of as a blueprint, or a set of
  instructions for building an organism.

17
Question from April 2006

• Erwin Chargaff studied the DNA of organisms
  within a single species. Chargaff discovered
  that the amount of adenine is about equal to the
  amount of thymine. Which of these explains why
  the ratio of adenine to thymine is nearly 11?
• Adenine and Thymine pair with each other.
• Adenine binds with phosphates, while thymine
  binds with nitrates.
• Adenine and thymine are identical in their
  chemical composition.
• Adenine bases contain a form of thymine.

18
Answer!!!!

• You guessed it! The answer is A!!!!!
• Remember, Adenine binds with thymine and guanine
  binds with cytosine.
• Each base is its own chemical, they are not like
  each other.