2.6 IB DNA & RNA Structure

What is the primary function of DNA?

• To determine the sequence of amino acids in a protein molecule

• To determine the sequence of saccharide monomers in a polysaccharide molecule

• To determine the sequence of traits in an individual

• To determine the sequence of fatty acids in a glycerol molecule

Answer explanation

DNA holds the code that determines which sequence the amnio acids will be arranged in for the primary sequence.

Tags

NGSS.HS-LS1-1

Which of the following differences between DNA and RNA is NOT true?

• DNA and RNA have a different sugar in their nucleotides

• RNA is a single-stranded helix

• RNA can be found in the nucleus and cytoplasm of the cell

• DNA is only found in the cell nucleus

• RNA has the following base paring: A-T, C-G

Answer explanation

Remember, RNA has U in it.

Tags

NGSS.HS-LS1-1

If 23% of the nitrogenous bases in a DNA molecule are guanine, what percentage of the nitrogenous bases will be adenine?

• 27%

• 23%

• 46%

• 54%

Answer explanation

23% guanine means that 23% must be cytosine.

So 46% is G-C, meaning 54% is A-T. Of that 54%, 27% is adenine.

Who is responsible for producing this image?

• Francis Crick

• James Watson

• Rosalind Franklin

• Maurice Wilkins

• Erwin Chargaff

Answer explanation

This is a very famous image, so make sure you recognize it and what it shows - the helical structure of DNA.

What does this image show?

• Double helical structure of DNA
• Triple Helical Structure of DNA
• Double helical structure of RNA
• Triple Helical Structure of RNA

Answer explanation

Rosalind Franklin took this photo and it was the key to unlocking the shape and structure of the DNA molecule.

Tags

NGSS.HS-LS1-1

The work of Erwin Chargaff allowed Watson and Crick to determine the rules of.......

• protein synthesis

• transcription

• hydrogen bonding

• nitrogenous base pairing

Answer explanation

Chargaff noticed that for x% or cytosine there was always x% of guanine, this was the foundation of complimentary base pairing theory.

Tags

NGSS.HS-LS1-1

Who was responsible for the model shown?

• Oswald Avery

• Watson and Crick

• Erwin Chargaff

• Rosalind Franklin

• Maurice Wilkins

Answer explanation

Watson and Crick were the model makers of the group.

The two strands of the DNA double helix are held together by what type of bond?

• hydrogen bonds
• peptide bonds
• covalent bonds
• ionic bonds

Answer explanation

It is a temporary bond that allows the bases to be revealed, so if it is temporary it has to be a hydrogen bond.

Tags

NGSS.HS-LS1-1

What determines the code of a DNA molecule?

• the structure of the nitrogenous bases

• the sequence of the nitrogenous bases

• the type of pentose sugar

• the frequency of nitrogenous bases

Answer explanation

The code is in the sequence of nitrogenous bases.

Tags

NGSS.HS-LS1-1

Which bases are purines?

• A & T
• C & T
• C & G
• A & G

Answer explanation

Purines has a 2-ring structure and are adenine and guanine. A way to remember is they both have 2-n's in their names!

Tags

NGSS.HS-LS1-1