Genetics : Chapter 2

What is a gene?

a length of chromosome made of DNA; the basic unit of inheritance

What is heredity?

The genetic passing on of traits from one generation to another.

What is DNA?

Deoxyribonucleic acid, or DNA, is the molecular unit of heredity, containing the genetic information responsible for the development and function of an organism.

What is the structure of DNA?

it is a double stranded helix that is a polymer made up of many monomer subunits called nucleotides.

What are nucleotides?

A monomer subunit of a nucleic acid, consisting of a phosphate group bound to a five-carbon sugar, which in turn is bound to a nitrogenous base.

What is a polymer?

a molecule made from many repeating subunits called monomers.

How do the nitrogenous bases pair with each other?

Adanine (A) always pairs with Thymine (T) and Guanine (G) always pairs with Cytosine (C), This is called complementary base pairing.

How do the nitrogenous bases bind to complementary bases?

Hydrogen bonds hold them together.

How many hydrogen bond are needed for Guanine and Cytosine? and Adenine and Thymine?

3 hydrogen bonds for GC, 2 for AT

Which bases have a double ring structure? and what does this make them?

Guanine and Adenine, this makes them purines

Which bases have a single ring structure, and what does this make them?

Thymine and Cytosine, this makes them pyrimidites.

What is chromatin?

a mixture of DNA and proteins that form chromosomes.

What is a chromosome?

A thread-like structure of tightly wound DNA and proteins called histones.

What are centomeres?

A structure that holds two sister chromatids together

What are sister chromatids?

two copies of the same chromosome, conneted at a telomere.

What are telomeres?

Structures made from DNA and proteins that protect protect the ends of chromosomes.

What are autosomes?

any chromosome that is not a xes chromosome.

what are xes chromosomes?

A specialized pair of chromosomes that determine the biological gender of an individual.

What is transcription?

The first stage in protein synthesis in which the base sequence of DNA is copied into RNA.

What nitrogenous base is replaced by Uracil in mRNA

Thymine

What is the process of transcription?

RNA polymerase binds to the gene being copied, causing the DNA to unwind, allowing for the enzyme to read code on one of the DNA strands. From there it follows the same pairing system as DNA, forming messager RNA, which peels back and heads towards the ribosomes.

What is translation?

The second stage of protein synthesis in which a sequence of mRNA is translated into a sequence of amino acids.

What is the process of translation?

the nitrogenous bases within the mRNA are read in codons, which each codon specifiies which amino acid is added to a chain of amino acids, called a polypetide chain. This repeats until the polypeptide chain stops and the amino acids wrap up to form a functioning protein.

What are codons?

A chain of 3 nucleotides that code to a specific amino acid.

What is mitosis?

the splitting of a cell to become 2 identical cells, that is common for growth and repair of an organism.

What is the process of mitosis?

Follows IPMAT, starts at prophase, where chromatin forms X shaped chromosomes, then metaphase, where all the chromosomes line up in the middle of the cell, then anaphase, where the chromosomes are pulled to the ends of the cell, and finally telophase, where the chromsomes decondense back into chromatin, making 2 diploid cells.

What is meiosis?

The process of the production of 4 unique gametes.

What is the process of meiosis?

Follows the same PMAT, but instead does it 2 times, and creates 4 unique haploid cells

What are haploids?

Contain only a single set of chromosomes.

What are diploids?

Have a 2 full sets of chromosmes, one from each parent.