Topic 3 - Dna Flashcards
(17 cards)
What is the basic unit of DNA?
Nucleotide
Nucleotides consist of a pentose sugar, a phosphate group, and a nitrogenous base.
What type of replication does DNA undergo?
Semi-conservative replication
In semi-conservative replication, each new DNA molecule contains one original strand and one new strand.
What is the structure of DNA?
Double helix
DNA is composed of two strands that are antiparallel and held together by hydrogen bonds between complementary bases.
What are the nitrogenous base pairs in DNA?
Adenine-Thymine, Cytosine-Guanine
These pairings are fundamental to the structure of DNA and its replication.
What type of chromosomes do eukaryotic cells have?
Long, thin, linear chromosomes associated with proteins called histones
In contrast, prokaryotic DNA is short and circular.
What are homologous chromosomes?
Matching chromosomes that are the same size and have the same genes
They may carry different alleles for those genes.
What is the sugar component of DNA?
Deoxyribose
This distinguishes DNA from RNA, which contains ribose.
What is the difference between DNA and RNA in terms of strands?
DNA is double-stranded while RNA is single-stranded
This structural difference affects their functions in the cell.
What are the types of RNA?
mRNA, tRNA, rRNA
Each type of RNA has a specific role in protein synthesis.
What is the function of DNA helicase during replication?
It breaks hydrogen bonds between bases, unwinding the DNA
This allows the original strands to act as templates for new strands.
What is a polynucleotide?
A polymer of nucleotides
Polynucleotides form the backbone of DNA and RNA.
Fill in the blank: The ends of a DNA strand are called the _______ and the _______.
5’ end, 3’ end
These designations refer to the orientation of the sugar-phosphate backbone.
True or False: DNA replication is a carefully controlled process.
True
This control helps to preserve genetic information but mutations can still occur.
What are common types of DNA mutations?
Substitution, Deletion, Addition, Duplication, Inversion, Translocation
Each type of mutation can lead to changes in protein synthesis and function.
What role do hydrogen bonds play in DNA?
They hold the two strands of DNA together
Hydrogen bonds form between complementary nitrogenous bases.
What is the sugar-phosphate backbone of DNA made of?
Alternating sugar and phosphate groups
This backbone provides structural support for the DNA molecule.
What is the difference between heterozygous and homozygous?
Heterozygous has different alleles; homozygous has the same alleles
These terms describe the genetic composition of an organism.
