Nucleic Acids

Where is DNA primarily found?

The nucleus of most cells

How many pairs of chromosomes does each person have?

23

There are 22 pairs of what kind of chromosomes?

Autosomal

There is one pair of what kind of chromosome?

Sex

What is the genetic information in DNA utilized as?

As instructions for the production of proteins at the cellular level

What are somatic cells?

They are bodily cells (aside from gametes)

What are diploid cells?

Cells that contain 2 copies of each chromosome in the genome

What are haploid cells?

Cells that contain only one set of chromosomes

Are somatic cells diploid or haploid?

Diploid

What are germ cells?

(Gametes) the sperm and the egg

Are germ cells haploid or diploid?

Haploid

Nucleic acids RNA and DNA are composed of which type of polymer?

Nucleotides

Nucleotides contain what 3 components?

1. Sugar molecule (ribose for RNA and deoxyribose for DNA)

2. Phosphate group

3. Nitrogenous group

How is the phosphate group of RNA/DNA utilized?

It is utilized for the polymerization of the nucleotides

What is the sugar molecule of nucleotides utilized for?

For the structural backbone of the nucleic acid

What is the nitrogenous base of the nucleotides utilized for?

For representing the “alphabet” of the genetic code

If nucleoTIDES are a (1) sugar, (2) a base, (3) a phosphate group then what are nucleoSIDES?

A sugar and a base WITHOUT the phosphate group

(Instead with a OH group)

What kind of bonds form between the phosphate group of a 5’ carbon and the hydroxyl group of a 3’ carbon?

Phosphodiester bond

5’ and 3’ are important for understanding what?

For understanding that RNA and DNA have distinct ends: the 5’ end and the 3’ end

What are the 2 families of nitrogenous bases?

1. Purines

2. Pyrimidines

When does base pairing take place?

In double stranded DNA molecule and in interactions between DNA and RNA

What are the 2 complementary base pairings in DNA?

1. Cytosine (C) and guanine (G)

2. Adenine (A) and thymine (T)

What are the 2 complementary base pairings in RNA?

The same as in DNA except uracil (U) replaces thymine

What type of bonding explains the pairing relationship?

Hydrogen bonding

DNA is composed of what type of strands?

Anti parallel strands

Is RNA a single or double strand?

Single strand

What is chromatin?

DNA complexed with structural proteins

How is DNA packaged up in the nucleus?

As two complementary strands of polynucleotides in packages called chromosomes

Which proteins serve structurally for the coiling and packaging of DNA?

Histones

What does RNA lack that DNA doesn’t?

The continuous helix structure. Instead forms loops

Is RNA also composed of nucleotides joined by 3’ and 5’ phosphodiester bonds?

Yes

What are the 3 types of RNA?

1. mRNA

2. .rRNA

3. .tRNA

When and where is mRNA generated?

During transcription in the nucleus from a gene

What does mRNA serve as?

Serves as an RNA “complementary copy” or TRANSCRIPT of the DNA sequence for translation into a protein in the cytoplasm

What is the purpose of rRNA?

To combine with certain proteins to form ribosomes

Is rRNA coding, or non-coding in nature?

Non-coding

What are ribosomes?

Protein synthesis complexes that are directly involved in translation of mRNA codes into protein

What is the purpose of tRNA?

To carry an amino acid to ribosomes for incorporation into a polypeptide chain

What do tRNA contain?

An anticodon portion of 3 nucleotides that pair up with mRNA codons

How many different tRNA molecules are in a cell?

20

There is one type of tRNA for each type of what?

Amino acid

What shape is tRNA?

Cloverleaf shape

A cell’s genome must be replicated during what?

Cell division

Why must a cell’s genome be reproduced during cell division?

So that each daughter cells has a copy of the genetic information

In eukaryotes multiple _________ form along the double stranded DNA complex

Replication forks

Each strand of a double helix can serve as what?

A template for replication

What are DNA polymerases’ role in the replication process?

They add nucleotides to the new, growing strand in a 5’-3’ direction

(The original’s direction is 3’-5’)

What components are needed in order to start the replication process?

Segments of RNA called RNA primers

Does DNA polymerase replicate nucleotides in the lagging strand of DNA or in the leading strand?

It replicates nucleotides continuously in the leading strand

What happens to the lagging strand?

It is synthesized discontinuously by joining Okazaki fragments

How long are Okazaki fragments?

150-200 base pairs long

Okazaki fragments are added onto the growing strand of DNA by what?

DNA ligase

What phase of the cell cycle does DNA replication occur?

The “S” (synthesis) cycle

How many mitochondria do cells contain?

Hundreds to thousands of DNA containing mitochondria

What shape is mtRNA?

Circular (like plasmid) with a heavy strand and a light strand

.mtRNA codes for how many genes?

Codes for roughly 37 genes in 16.5k base pairs

The genes in mtRNA code for structures involved in what?

Oxidative phosphorylation (ETC) such as enzymes for various mRNA and tRNA molecules

Mitochondrial DNA is passed down to offspring via what parent?

The mother only

What is the basic unit of heredity?

A gene

What determines a specific physiologic of physical trait?

The DNA sequence

What do most genes code for?

A specific protein that have specific bodily functions

What are alleles?

Different versions of the same gene

What is a dominant allele?

An allele where you only need one copy for a trait to be physiologically demonstrated

What is a recessive allele?

An allele where you need 2 copies for the trait to be expressed

What does the Mendelian inheritance principal describe?

The frequency in which dominant vs. recessive traits are passed down genetically based on the genetic makeup of the parents

Which tool helps answer the questions asked by the Mendelian principal?

(Which percentage of offspring will exhibit the dominant trait?; which percentage of offspring will exhibit the recessive trait?”

The punnett square