3C1 Heredity Flashcards
Explain how structure, function, and processes of DNA and RNA underlie genetic inheritance and variation. (81 cards)
What does DNA stand for?
Deoxyribonucleic acid
DNA is a molecule that carries genetic instructions for the development, functioning, growth, and reproduction of all known living organisms.
What does RNA stand for?
Ribonucleic acid
RNA plays a role in protein synthesis and can act as genetic material in some viruses.
What is the shape of the DNA molecule?
Double helix
DNA’s double-helix structure was discovered by James Watson and Francis Crick, supported by Rosalind Franklin’s X-ray diffraction data.
What sugar is found in DNA?
Deoxyribose
Deoxyribose is a 5-carbon sugar that lacks an oxygen atom at the 2’ position, distinguishing it from ribose in RNA.
Which base is unique to RNA?
Uracil
Uracil replaces thymine in RNA and pairs with adenine during base pairing.
True or False:
Thymine is found in RNA.
False
Thymine is found only in DNA, whereas RNA contains uracil instead.
What are the four nitrogenous bases in DNA?
- Adenine
- Thymine
- Cytosine
- Guanine
Adenine pairs with thymine, and cytosine pairs with guanine through complementary base pairing.
What are the building blocks of DNA?
Nucleotides
Each nucleotide consists of a phosphate group, deoxyribose sugar, and a nitrogenous base.
Fill in the blank:
In DNA, adenine pairs with _______.
Thymine
Adenine pairs with thymine through two hydrogen bonds, maintaining the double-helix structure.
What is the function of DNA?
Storing genetic information.
DNA serves as the blueprint for all cellular processes and is passed from parent to offspring.
True or False:
RNA is double-stranded like DNA.
False
RNA is typically single-stranded, although it can fold into complex shapes for specific functions.
Fill in the blank:
DNA replication occurs in the ________ of eukaryotic cells.
nucleus
DNA replication takes place during the S-phase of the cell cycle in the nucleus.
What is transcription?
The process of creating RNA from a DNA template.
This occurs in the nucleus where RNA polymerase synthesizes messenger RNA (mRNA).
What are the three types of RNA?
- mRNA
- tRNA
- rRNA
mRNA carries genetic code, tRNA brings amino acids, and rRNA forms ribosomes.
What is the function of mRNA?
It carries the genetic code for protein synthesis.
Messenger RNA (mRNA) transfers genetic information from DNA to ribosomes for translation.
Where does transcription occur in eukaryotic cells?
In the nucleus.
In eukaryotes, DNA is located in the nucleus, so transcription must occur there.
What enzyme catalyzes transcription?
RNA polymerase
This enzyme binds to the DNA template strand and synthesizes complementary RNA.
True or False:
Transcription occurs in the cytoplasm of prokaryotes.
True
In prokaryotes, transcription occurs in the cytoplasm because they lack a nucleus.
What are the three main stages of transcription?
- Initiation
- Elongation
- Termination
Initiation begins the process, elongation builds the RNA strand, and termination ends transcription.
Fill in the blank:
RNA polymerase binds to the _______ during transcription initiation.
promoter
The promoter is a DNA sequence that signals the start of transcription.
What is the central dogma of molecular biology?
DNA → RNA → Protein
The central dogma explains the flow of genetic information: DNA is transcribed into RNA, which is then translated into proteins.
Why is the central dogma important?
It explains how genetic information leads to protein synthesis.
The central dogma outlines the essential flow of information needed for gene expression and protein production.
Fill in the blank:
During translation, amino acids are brought to the ribosome by _______.
tRNA
(transfer RNA)
tRNA contains anticodons that pair with mRNA codons, allowing amino acids to assemble into proteins.
Define:
codon
A sequence of 3 nucleotides that code for a specific amino acid.
Also referred to as triplet code, these sequences exist in both DNA and RNA.
For example, the codon “CAG” codes for the synthesis of the amino acid glutamine.