“12th Class Biology Chapter 20 Quiz: Chromosomes and DNA” explores the molecular structures that carry genetic information in living organisms. This chapter delves into the role of chromosomes and DNA (deoxyribonucleic acid) in heredity, gene expression, and inheritance. Chromosomes, found in the nucleus of eukaryotic cells, contain long strands of DNA that are responsible for encoding the genetic instructions necessary for growth, development, and functioning of all living organisms. Strengthen your knowledge with our MDCAT Quiz and free flashcards, which will help reinforce key concepts and assist with your exam preparation.
Chromosomes: Structures of Genetic Material
Chromosomes are thread-like structures made up of DNA and proteins that are found in the nucleus of eukaryotic cells and the cytoplasm of prokaryotic cells. In humans, there are 23 pairs of chromosomes, each carrying a set of genes that determine various traits. Chromosomes can be seen during cell division, especially during the stages of mitosis and meiosis.
Each chromosome has two chromatids that are joined together at a very specific region called the centromere. These chromatids are actually made up of a very long chain of DNA, which is coiled and packaged in such a compact manner within this structure. Genetic information on chromosomes is organised into genes—each of which codes for a specific protein or function. The arrangement and number of chromosomes vary across different species. Any change in the number or structure of chromosomes leads to genetic disorders.
DNA: The Genetic Blueprint
DNA (Deoxyribonucleic Acid) is the molecular blueprint that carries genetic information. Nucleotides are the building blocks of DNA, and each consists of a phosphate group, a sugar molecule (deoxyribose), and a nitrogenous base. The four nitrogenous bases in DNA are adenine (A), thymine (T), cytosine (C), and guanine (G). These base pairs in a particular manner: adenine with thymine and cytosine with guanine—this gives DNA its characteristic structure, the double helix.
The sequence of nucleotides along a DNA strand encodes the information needed for protein synthesis and the regulation of cellular functions. DNA replication is the process by which a cell makes a copy of its DNA before cell division, so the genetic information is passed on to the daughter cells. Transcription and translation are the processes by which the information in DNA is used to synthesize proteins, which are essential for the structure and function of cells.
MDCAT Quiz: Chromosomes and DNA
Test your knowledge of chromosomes and DNA with our MDCAT Quiz. The quiz will cover critical topics including the structure of chromosomes, DNA replication, gene expression, and mechanisms of inheritance. It will help in reinforcing your knowledge and prepare you for related questions in your exams.
- Test Name: 12th Class Biology Chapter 20 Quiz
- Type: Quiz Test
- Total Questions: 30
- Total Marks: 30
- Time: 30 minutes
Note: Answer of the questions will change randomly each time you start the test, once you are finished, click the View Results button.
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Free Flashcards for Chromosomes and DNA
Review important concepts with our free flashcards on chromosomes and DNA. These flashcards focus on key terms such as chromatids, nucleotides, base pairing, and genetic inheritance. Using flashcards is an effective way to memorize definitions and understand complex processes related to DNA structure and function.
Which nitrogenous base is found in RNA but not in DNA?
Uracil
What is the role of ribosomes in protein synthesis?
Site of protein synthesis
What is the term for the specific sequence of nucleotides that signals the start of translation?
Start codon
What is the function of rRNA during protein synthesis?
Forms the structure of ribosomes
What is the complementary base pair for adenine in RNA?
Uracil
What is the name of the enzyme that proofreads and repairs mistakes during DNA replication?
DNA polymerase
What is the term for the process of copying genetic information from DNA to RNA?
Transcription
What is the function of tRNA during protein synthesis?
Carries amino acids to the ribosome
What is the structure of DNA described as when it consists of two strands twisted around each other?
Double helix
Which nitrogenous base pairs with adenine in RNA?
Uracil
What is the term for the sequence of three nucleotides on tRNA that pairs with the codon on mRNA?
Anticodon
What is the name of the enzyme responsible for adding nucleotides to the growing RNA strand during transcription?
RNA polymerase
In eukaryotic cells, where does translation occur?
Ribosome
Which type of RNA carries the genetic information from DNA to the ribosome?
mRNA
What is the term for the specific region of a chromosome where a gene is located?
Locus
What is the process by which RNA is synthesized from a DNA template called?
Transcription
What is the complementary base pair for cytosine in DNA?
Guanine
What is the role of mRNA in protein synthesis?
Carries genetic information from DNA to the ribosome
What is the term for a change in the sequence of nucleotides in DNA?
Mutation
What is the name of the enzyme responsible for joining Okazaki fragments during DNA replication?
DNA ligase
In eukaryotic cells, which organelle is responsible for protein synthesis?
Ribosome
Which type of RNA carries amino acids to the ribosome during protein synthesis?
tRNA
What is the term for the three-nucleotide sequence on mRNA that codes for a specific amino acid?
Codon
What is the name of the process by which the genetic code carried by mRNA is decoded to produce a specific protein?
Translation
Which nitrogenous base pairs with guanine in DNA?
Cytosine
What is the function of RNA polymerase during transcription?
Synthesizes RNA
What is the structure of DNA known as when it is tightly coiled around proteins?
Chromatin
What is the term for the specific sequence of nucleotides that codes for a particular protein?
Gene
Which enzyme adds new nucleotides to the growing DNA strand during replication?
DNA polymerase
What is the process of synthesizing RNA from a DNA template called?
Transcription
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