DNA and Chromosomes

An illustration of a molecule that stores genetic code for cellular use is shown. The ordering of base pairs (A, T, G, and C) determine what amino acids will be used when making protein.

What is the name of this molecule?

What is a nucleosome?

• protein in nucleus that folds DNA

• strand of DNA

• part of the nucleus

• DNA wrapped around a histone complex

The DNA molecule's structure is described as a double helix. Some people describe it as looking like a twisted ladder.

Which component of the DNA molecule would make up the rungs (or steps) on the ladder?

• nitrogenous bases

• 5' ends

• phosphate groups

• deoxyribose sugar

Match the following

• 4

• Phosphate

• 2

• Pyrimidine

• 3

• Purine

• 5

• Deoxyribose (sugar)

• 1

• Complimentary Base Pairing

Purines and pyrimidines are two groups of organic compounds that serve as the building blocks for nucleic acids.

Which statement is true about the relationship between purines and pyrimidines?

• Each purine bonds with a specific pyrimidine.

• Purines make up the base pairs in DNA, and pyrimidines make up the base pairs in RNA.

• In a DNA molecule, pyrimidines carry the genetic code and purines provide structural support.

• A purine only forms bonds with another purine.

What is the function of nucleosomes in relation to DNA?

• folding DNA, allowing it to fit into the nucleus

• joining nucleotides in order to produce DNA molecules

• linking the single, circular chromosome in prokaryotic cells

• to be the backbone of DNA

Match each nitrogenous base to the nitrogenous base it typically pairs with in DNA.

Adenine binds with ​ (a)  

Guanine binds with ​ (b)  

• Thymine
• Cytosine

Complimentary strands of DNA are two strands that can bind together. Consider the given strand.

ATTACCGATTACCG

Look at the given strand and choose its correct complimentary strand.

• ATTACCG

• TAATGGC

• GCCATTA

• CGGCAAT

Select all items that comprise chromosomes.

• DNA

• Nucleus

• centrioles

• protein molecules

Choose all statements that are true about chromosomes.

• The location of a gene on a chromosome is called a locus.

• The combined structure of DNA and proteins, visible during the replication of a cell, is called chromatin.

• A chromosome is a structure found in the nuclear region of a cell that is composed completely of proteins.

• Many nucleosomes are coiled, condensed, and looped together to form a single chromosome.