Question

period: 3rd
date: 10/20/25
dna structure and its parts: exploring the blueprint of life
deoxyribonucleic acid (dna) is the molecule that contains the genetic instructions for
the development and function of living things. dna is found in the nucleus of your cells
and is made up of smaller parts that work together to store information. the structure of
dna is often described as a double helix, which looks like a twisted ladder. the sides of
this ladder are made up of a phosphate backbone and deoxyribose sugars. the
ungs\
of the ladder are made of pairs of nitrogenous bases. there are four nitrogenous bases in
dna: adenine (a), thymine (t), cytosine (c), and guanine (g). these bases pair up in a
specific way: adenine with thymine, and cytosine with guanine. the discovery of dnas
structure in 1953 by james watson and francis crick, with help from rosalind franklins
x - ray images, changed our understanding of biology forever.
fill in the blank: phosphate, thymine, double helix, cytosine, deoxyribose, rosalind
franklin

1. the two main components of the dna backbone are

and

1. dna is shaped like a , which is often described

as a twisted ladder.

1. the four nitrogenous bases found in dna are adenine, thymine,

and guanine.

1. the scientist who took important x - ray images that helped discover dnas structure

was

1. in dna, adenine always pairs with

multiple choice questions: choose the correct answer from the choices for each
question.

1. what is the sugar found in the backbone of dna?

a) ribose
b) deoxyribose
c) glucose
d) fructose

Explanation:

1. The text states "The sides of this ladder are made up of a phosphate backbone and deoxyribose sugars." So the two main components of the DNA backbone are phosphate and deoxyribose.
2. The text clearly says "DNA is often described as a double helix, which looks like a twisted ladder."
3. The text lists "There are four nitrogenous bases in DNA: adenine (A), thymine (T), cytosine (C), and guanine (G)."
4. The text mentions "with help from Rosalind Franklin's X - ray images".
5. The text says "adenine with thymine" for base - pairing.

For the multiple - choice question: The text says "deoxyribose sugars" in the DNA backbone description.

Answer:

1. phosphate, deoxyribose
2. double helix
3. cytosine
4. Rosalind Franklin
5. thymine

Multiple - Choice: b) Deoxyribose