Intro_2_RNA_and_Chromosomes_Flashcards
What does RNA stand for?
Ribonucleic acid.
Is RNA single-stranded or double-stranded?
Single-stranded.
What are the basic building blocks of RNA?
Ribose sugar, phosphate group, and nitrogenous bases (A, G, C, U).
Which base does RNA have instead of Thymine (T)?
Uracil (U).
What is the backbone of RNA made of?
Alternating ribose sugars and phosphate groups.
How is RNA different from DNA in terms of sugar?
RNA has ribose sugar; DNA has deoxyribose sugar.
What is the function of messenger RNA (mRNA)?
Carries genetic code from DNA to ribosomes for protein synthesis.
What is the role of ribosomal RNA (rRNA)?
Forms the core of ribosomes and facilitates protein synthesis.
What does transfer RNA (tRNA) do?
Carries specific amino acids to ribosomes during protein synthesis.
What are non-coding RNAs (ncRNAs)?
RNAs that don’t code for proteins but regulate gene expression.
Give examples of ncRNAs.
microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and ribozymes.
What percentage of transcriptional output in eukaryotes is ncRNAs?
About 97%.
Name three functions of RNA.
Protein synthesis, gene regulation, and catalysis.
What is a ribozyme?
An RNA molecule with catalytic activity.
How does RNA size compare to DNA?
RNA molecules are much shorter than DNA.
How long are most RNA molecules?
A few thousand nucleotides.
How is RNA integrity assessed?
Using a denaturing agarose gel stained with ethidium bromide.
What does a 2:1 intensity ratio of 28S to 18S rRNA bands indicate?
Intact RNA.
What is chromatin?
A complex of DNA and proteins that make up chromosomes.
Who discovered chromatin?
Walther Flemming.
What is a nucleosome?
The basic unit of chromatin, with DNA wrapped around histone proteins.
What are the levels of chromatin structure?
DNA double helix, nucleosome, 30 nm fiber, chromatin loops, chromosomes.
What is euchromatin?
Less condensed chromatin that is gene-rich and transcriptionally active.
What is heterochromatin?
Highly condensed chromatin that is gene-poor and transcriptionally inactive.
Name the core histones in nucleosomes.
H2A, H2B, H3, and H4.
What is the role of linker histone H1?
Binds linker DNA and helps form higher-order chromatin structures.
What is the function of chromosomes?
To carry and protect DNA during cell division.
What is a karyotype?
An organized visual representation of an individual’s chromosomes.
What is the function of the centromere?
Attaches chromosomes to spindle fibers during cell division.
What are telomeres?
Repetitive DNA sequences at the ends of chromosomes that protect DNA from degradation.
How many nucleotides are in the human genome?
About 3.2 billion.
How many pairs of chromosomes are in the human genome?
23 pairs.
What percentage of the human genome codes for proteins?
About 2%.
What was the goal of the Human Genome Project?
To sequence the entire human genome.
When was the Human Genome Project completed?
In 2003.
What is genetic polymorphism?
Variations in DNA sequences among individuals or populations.
What is a single nucleotide polymorphism (SNP)?
A DNA sequence variation involving a single nucleotide difference.
What are tandem repeats?
Repetitive DNA sequences where the number of repeats varies between individuals.
What is DNA fingerprinting used for?
Forensic investigations and paternity testing.
How do RNA and DNA differ in structure?
RNA is single-stranded; DNA is double-stranded.
What sugar is found in RNA but not in DNA?
Ribose (DNA has deoxyribose).
What base does RNA have that DNA does not?
Uracil (DNA has Thymine).
What is a nucleotide?
The building block of DNA and RNA, consisting of a sugar, phosphate group, and nitrogenous base.
What is a nucleoside?
A nucleotide without the phosphate group.
What are purines?
Double-ring nitrogenous bases (A and G).
What are pyrimidines?
Single-ring nitrogenous bases (C, T, and U).
What bonds link nucleotides in RNA and DNA?
Phosphodiester bonds.
What does the RNA backbone consist of?
Ribose sugars and phosphate groups.
What is the function of mRNA?
Carries the genetic code from DNA to ribosomes for translation.
What is the role of histones in chromatin?
Organizing and compacting DNA into nucleosomes.
