Chapter 3: Genetics: Nature and Structure of Genetic Code

What are the different ways that genetics are studied?

There are 5 different ways that genetics are studied. This includes:

1) Cellular and Molecular genetics
2) Classical or Mendelian Genetics
3) Population Genetics
4) Phylogenetics
5)Behavioral Genetics

What is Cellular and Molecular genetics?

The study of genetics at the building block level (cells). It is also the study of the level of genetic transmission.

What is Classical or Mendelian Genetics?

This type of study looks at the pedigree of related individuals to track how traits are passed from one generation to the next

What is a pedigree?

A diagram used in the study of human genetics that shows the transmission of a genetic trait over generations of a family

What is Population genetics?

The study of genetic variation within and between populations to gin insight on the evolutionary histoy of those populations and species as a whole.

What is Phylogenetics?

Concerned with determining evolutionary relationships between species by using treelike diagrams that visually indicate how closely or distantly species are related to one another

What is behavioral genetics?

Trying to understand how the behavior of animals, including humans, is influenced by genetics

What is a prokaryote?

A single celled organism that has no nucleus

What is a eukaryote?

A multicellular organism that has a nucleus

What is the Plasma Membrane?

Regulates the passage of material into and out of the cell and governs communication and coordinate activity between cells

What is the Cytoplasm?

The region within the cell membrane that surrounds the nucleus; it contains organelle, which carry out the essential functions of the cell, such as energy production, metabolism, and protein synthesis

What are organelles?

The structures in the cell that help maintain the cell and carry out its functions

What are Somatic cells?

The cells in the body that are not sex cells

What are gametes?

The sex cells in the body

How many different types of cells do humans have?

200 different types of tissue.

What are stem cells?

Undifferentiated cells found in the developing embryo that can be induced to differentiate into wide variety of cell types

What is the most prominent structure in the cytoplasm of eukaryotic cells?

The nucleus

What is found in the nucleus?

DNA

What are the primary functions of DNA?

Protein synthesis an cellular respiration

What are proteins?

Complex molecules formed from chains of amino acids or from a complex of polypeptides

What is protein synthesis?

The assembly of proteins from amino acids that occurs at ribosomes in the cytoplasm and is based on information carried by mRNA

What is RNA?

Single stranded and can be found in the nucleus and the cytoplasm

What is the Mitochondria?

Capsule-shaped organelles that produce ATP which helps fuel the activities of the cell

What is unique about the Mitochondria?

They have their own DNA

What is the Endoplasmic Reticulum?

Organelle in the cytoplasm consisting of folded membrane. There is Rough ER and Smooth ER. Rough ER has ribosomes but smooth er does not

What are Ribosomes?

Structures composed of RNA and are the site of protein synthesis

What is a nucleotide?

The basic unit of DNA and RNA. It consists of a phosphate, sugar, and base

What is an enzyme?

A complex protein molecule that mediates a chemical or biochemical reaction

What does hemoglobin do?

Transports oxygen

What do hormones do?

Influences the activity or physiology of cells in a different location

What do enzymes do?

Catalyze countless biochemical reactions in cells

What are amino acids?

molecules that form the basic building blocks of proteins. There are 20 different amino acids and 9 are essential

What is a polypeptide?

A molecule made up of a chain of amino acids

What is a genetic code?

The system that helps DNA nd RNA get the information for synthesizing proteins from the amino acids

What is a codon?

A triplet of nucleotide bases in mRNA that specifies an amino acid or the initiation or termination of a polypeptide sequence

What is a gene?

The fundamental unit of heredity. Consists of a sequence of DNA bases that carries the information for synthesizing a protein. Genes also occupy a specific chromosomal locus

What is transcrption?

Occurs in the nucleus of the cell

What is translation?

Also called protein synthesis which occurs in the cytoplasm of a cell

What is mRNA?

A strand of RNA synthesized in the nucleus as a compliment to a specific gene. It carries the information for the sequence of amino acids to make a specific protein into the cytoplasm

What is tRNA?

RNA molecules that bind to specific amino acids and transport them to ribosomes to be used during protein synthesis

Who made the term "gene?"

Wilhelm Johannsen in 1909

How many proteins can be made by humans?

90,000+

Is a gene a separate structure?

No a gene is a location where a code sequence is located - a locus

When does a mutation occur?

When the sequence of bases is altered

What is an exon?

Active code it does get translated into a protein

What are introns?

Regulatory regions and it is 24% of base pair sequences

What are non coding regions?

Resting DNA and it makes up 75%

How does protein synthesis occur?

First transcription occurs in the nucleus and turns DNA into a RNA message or mRNA. Then the mRNA is read and capped then goes to the cytoplasm to be translated. Translation occurs in the cytoplasm and the mRNA is read an the information is used to make a protein

What is an anicodon?

A sequence of three nucleotides forming a unit of genetic code in a tRNA molecule corresponding to a complementary codon in mRNA

What is chromatin?

When DNA is in a state of dispersed, uncoiled strands, supported by proteins

What is mitois?

The process of somatic cell division

What is meiosis?

Cell division that occurs in the testes and ovaries/ovum that leads to the formation of gametes

What is a chromosome?

A discrete structure composed of condensed DNA and supporting proteins. It is coiled and tightly wound

What is a centromere?

The location where the sister chromatids attach to each other

What is the locus?

The location of a gene on a chromosome

What is an allele?

Alternate version of a gene

What is homozygous?

To have the same allele at the loci for a gene on both members of a pair of homologous chromosomes

What is heterozygous?

Having two different alleles at the loci for a gene on a pair of homologous chromosomes

What is different in the process of meiosis than in the process of mitosis?

In meiosis there are two stages of each phase and in prophase 1 crossing over occurs.

What is crossing over?

The recombination of genetic material between pairs of homologous chromosomes.

What is a karyotype?

A picture that shows all the chromosomes in a single somatic cell

How many different chromosomes do humans have?

Haploid: 23

Diploid: 46

What is a non disjunction error?

The failure of homologous chromosomes to separate properly during cell division.

What is a monosmy?

When on chromosome in a pair is absent

What is a trisomy?

When there is an extra chromosome

What is a genome?

The sum total of all the genes carried by an individual

What is a polymerase chain reaction?

A method for amplifying DNA sequences using the Taq polymerase enzyme.

What is mitochondrial DNA?

Small loop of DNA found in the mitochondria. It is clonally and maternally inherited.