16 Questions
What is the study of heredity and the variation of inherited traits known as?
Genetics
What is the sugar molecule that is part of a nucleotide?
Deoxyribose
How are nucleotides linked together in a DNA molecule?
By phosphodiester bonds
Which of the following is a characteristic of the DNA molecule?
It is a twisted, double-stranded structure
What is the nitrogenous base that always pairs with thymine (T) in a DNA molecule?
Adenine (A)
What is the term for the stable and specific structure formed by hydrogen bonds between base pairs?
Double helix
What is the primary function of the genetic code in DNA?
To determine the structure and function of proteins and other essential biological molecules
What is the main difference between the sugar molecules in DNA and RNA?
Number of carbon atoms
What is the term for the units of nucleic acids, such as DNA and RNA?
Nucleotides
What is the function of the phosphate group in a nucleotide?
To form a phosphodiester bond with the next nucleotide
What is the relationship between chromosomes and genes?
Chromosomes are composed of many genes
What key principle of DNA is highlighted by Chargaff's rules?
Complementary base pairing
In DNA, what is the significance of the 5' and 3' ends of each strand?
Indicates the direction of DNA replication
How do pyrimidines and purines contribute to maintaining Chargaff's rule?
Pyrimidines pair with purines
Which genetic component contains the information necessary for synthesizing proteins or RNA?
Genes
How many pairs of chromosomes are found in human cells?
46 pairs
Study Notes
Genetics: Understanding the Basics
Genetic Components
Genetics is the study of heredity and the variation of inherited traits, which is passed from one generation to another. The genetic material of an organism is called deoxyribonucleic acid (DNA). DNA is a nucleic acid that contains the instructions for the development, growth, reproduction, and functioning of all living organisms.
The DNA Molecule
The DNA molecule is a long, twisted, double-stranded structure made up of nucleotides. Each nucleotide consists of a sugar called deoxyribose, a phosphate group, and a nitrogenous base. DNA uses four types of nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Nucleotides are linked together by phosphodiester bonds, forming a polymerized chain of nucleotides.
Nucleotide Structure
The nucleotide structure consists of a sugar-phosphate backbone and a nitrogenous base. The phosphate group is attached to the 5' carbon of the deoxyribose sugar, while the nitrogenous base is bonded to the 1' carbon of the deoxyribose. The base is also connected to the 3' carbon of the neighboring nucleotide via a phosphodiester bond, forming a continuous strand of nucleotides.
DNA Structure
The DNA molecule adheres to Chargaff's rules, which state that A always pairs with T, and C always pairs with G. These base pairs are held together by hydrogen bonds, which form a stable and specific structure called the double helix. The double helix is antiparallel, meaning that the two strands run in opposite directions and have 5' and 3' ends.
Chromosomes vs Genes
While chromosomes are physical structures within the nucleus of a cell that contain an organism's genetic material, genes are segments of DNA that contain the information for a specific trait or characteristic. Chromosomes are made up of long, linear DNA molecules, while genes are specific sections of those molecules. Chromosomes are typically visualized during cell division, while genes are studied through genetic analysis and sequencing.
Test your knowledge on the genetic components, DNA molecule, nucleotide structure, DNA structure, chromosomes, and genes. Topics include nucleotides, nitrogenous bases, phosphodiester bonds, Chargaff's rules, double helix, and the relationship between chromosomes and genes.
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