quiz 1: genetics (lesson 1-3)

the study of heredity and variation of living organisms and how genetic information is passed down from one generation to another

a plant or animal cell that forms the body of the organism; excludes reproductive cells

the physical structure of DNA formed by double stranded molecules of nucleic acids

• the basic building block of nucleic acids • made of phosphate, sugar and a base

a chromosome that is not involved in determining the sex of an organism (the first 22 chromosomes)

a chromosome that contains the same sequence of genes as another chromosome

a different form of the same gene (variation of genes)

a part of a chromosome that governs the expression of a trait and is passed on to off spring; it has a specific DNA sequence

a photograph of pairs of homologous chromosomes in a cell

• deoxyribonucleic acid • contains genetic code that is unique to every individual

• different for every different type of cell • can be minutes, hours or years

• major period of growth for a cell • cell is synthesizing new molecules in preparation for the next phase

• DNA is replicated • DNA exists as in condensed fibres called chromatin

cell synthesizes more molecules prior to mitosis

• chromatin condenses into chromosomes which contain DNA • sister chromatids and chromosomes joined together by centromere • nuclear membrane breaks down, spindle apparatus separates and moves to opposite poles

• spindle fibres guide the chromosomes to the equator • spindle fibres from opposite poles attach to the centromeres

• centromere splits apart and sister chromatids separate • spindle fibres shorten, pulling chromosomes to opposite poles • at the end, 1 complete set of chromosomes have been gathered at each pole

• begins when chromosomes have reached opposite ends of the cell • chromosomes unwind into less visible strands of chromatin • spindle fibres breakdown, nuclear membrane forms around chromosomes, nucleus forms

• indentation forms in the cell membrane along equator if the cell (deepens until the cell is pinched in 2) • cytoplasm divides equally between 2 halves of the cell, creating 2 daughter cells

• adenine • thymine • guanine • cytosine