SBI3U - Genetics

• The failure of homologous chromosomes to move to opposite poles of the cell during meiosis;

• results in an abnormal number of chromosomes in the daughter cells

• Trisomy (24)

• Monosomy (23)

Chromosome pair #1-22

• Chromosome pair 23

• determines gender

• female (XX)

• Male (XY)

The chromosomes of an individual that have been sorted and arranged according to size and shape

Turner Syndrome

• Sterile, short/stockier build

• Most XO fetuses usually die.

• Disorders of Sex Chromosome Non-disjunction

XXX

(Female)

• 1/1000 female births

• poorly diagnosed

Klinefelter Syndrome

• Can exhibit female characteristics,

• Disorders of Sex Chromosome Non-disjunction

Down syndrome

• round face, short height

• range of intellectual abilities

• Disorders of Autosomal Non-disjunction

Patau Syndrome

• serious developmental problems

• live several months (sometimes yrs)

• Disorders of Autosomal Non-disjunction

Edwards Syndrome

• many organ system failures

• most die before birth

• Disorders of Autosomal Non-disjunction

• because all the eggs a woman will produce have begun their development (to Prophase I) by the time she is born.

• Therefore, a much greater chance exists for problems to occur in the gametes of women than men.

• Gametes only carry one allele for a gene

• Different characteristics are inherited independently from one another

• a diagram of of an individual's ancestors used in human genetics

• to analyze the Mendelian inheritance of a certain trait;

• also used for selective breeding of plants and animals.

• The formation of sex cells in meiosis

• Egg cell formation

• The CYTOPLASM does NOT divide equally

• Daughter cells with less cytoplasm called POLAR BODIES

• Polar bodies will DIE therefore final product is A SINGLE OVUM (EGG CELL)

• Sperm cell formation is called

  • Cytoplasm is divided equally

  • Forms FOUR equal sized SPERM CELLS

  • Each sperm cell is SMALL AND STREAMLINED in size

Occurs when two different alleles control a characteristic, but neither is dominant so both are expressed or blended in the phenotype.

both allele products appear in the offspring at the same time.

Hemophilia, color blindness, male pattern balding,, muscular dystrophy

hemophilia:

• bleeding disorder in which the blood does not clot properly.

• This can lead to spontaneous bleeding as well as bleeding following injuries or surgery.

Muscular dystrophy:

• Over time, muscle weakness decreases mobility, making everyday tasks difficult.

• grows

• DNA replicates

• The cell performs its daily functions

• Spindle fibers form

• Nuclear membrane begins to dissolve

• Centrioles begin to move to opposite sides

• The spindle fibbers move the chromosomes to the equator

• spindle fibbers shorten and contract pulling apart chromosomes and pulling each sister chromatid

telophase:

• spindle fibre’s disappear

• nuclear membrane begins to reform

• the cell begins to divide

cytokinesis:

• the cell separates into two identical daughter cells

• the cytoplasm seperate’s

• in a process called synapsis, chromosomes pair up & bind to form homologous chromosomes forming a tetrad

• In a process called crossing over chromatids from homologous homologous chromosomes exchange allies to create genetic verity

• nuclear membrane dissolves

• spindle fibers form

• tetrads line up at the equator attached to the spindle fibers

• random assortment is when homologous pairs are randomly orientated to face opposite poles

• the accumulation of alkapton in the body

• kidney stones cause damage to cartilage

• recessive allele

• body creates thick sticky mucus that clogs the lungs

• blocks the release of enzymes from the pancreas

• recessive allele

• Accumulation of phenylalanine

• poor mental development and growth

• weak tooth enamel

• recessive allele

• nerve cells in the brain are effected

• deuteriation of muscles and physical abilities

• Tay Sachs Disease

• PKU (Phenylketonuria)

• Describe (cystic fibrosis)

• Alkaptonuria

• Albinism

• genetic disorder that causes accelerated aging in children. It is caused by a mutation

• dominate allele

• degeneration of nervous system that causes loss in muscular control and cognitive abilities

• dominate allele

• high levels of cholesterol accumulation in the blood

• dominate allele

• Progeria

• Huntington’s

• Hypercholesterolemia

Deoxyribonucleic acid

• In 1930 Hammering found out that genetic information is found in the nucleus

• Before that scientist had no idea DNA held genetic information

• Hershey and chase experiment confirmed that DNA carried genetic information

• Nucleotide

• Sugar (deoxyribose)

• nitrogenous base

• Phosphate

• Adenine (A)

• Thymine (T)

• Cytosine (C)

• Guanine (G)

A+T (%%A%%pple grow on %%T%%rees)

C+G (%%C%%ars go in %%G%%rudges)

• Changes to the gene or even chromosome.

• Can be helpful, harmful or have no impact depending on the location of the mutation and the impacts it could have

• substitution - one nucleotide is substituted for another

• insertion - an extra nucleotide(s) is inserted into a sequence of nucleotides

• deletion - a nucleotide(s) is removed from a sequence of nucleotides

• the information in the sequence of DNA nucleotides is read by ribosomes that make proteins.

• chromosomal mutation because it impacts 100s or 1000s of genes whereas a point mutation is an error in one gene.

Animal:

• have centrioles to organize spindle fibers

• forms a cleavage furrow when becoming two daughter cells

Plant:

• no centrioles so microtubles organize the spindle fibers

• forms a cell plate when separating into two daughters cells

• body cells dividing to two identical daughter cells

• production of gametes (sex cells) that are genetically unique

reproductive cells (sperm/egg)

• haploid 1n (one set of chromosomes)

carries 2 sets of chromosomes (parents)

• 2n