A&P Chapter 25: Genetics

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Genetics
The scientific study of inheritance and human diseases
Gene therapy
Treating fatal inherited disorders
informtion in the genetic code can cause what?
Diseases
BRCA gene tests for
Breast or ovarian cancer
BRCA1 and BRCA2
They are somewhere on DNA that makes a protein
ALS Gentic test look for
SOD1 on Chromosome 21 (found in 20%)
ALS
Amyotrophic Lateral Sclerosis

*Affects the muscle cells causing them to shrink

Human Genome
The entire collection of genetic material in each typical cell of the human body
Genetic testing using saliva (passive drool method) collects what type of cells?
Epithelial cells (Cell inside the cheek) makes a copy
Genetic Material — ______—-Code sequence for proteins—-_______
DNA Strands

Code for each amino acid

Gene
Each part of the DNA that makes proteins
Transfer of Genetic Material

CHROMOSOMES

Coiled up DNA packaged very tightly (contains the genetic material)
How many chromosomes do humans have?
46 X’s

22 autosome + 1 sex chromosome from each parent

Karyotype
Chart that we make to represent each persons set of chromosomes

Nuclear chromosomes is then cut and pasted, arranging each of the 46 chromosomes into number pairs of decreasing size to form a Karyotype.

Describe the chart
Describe the chart
What is an ideogram
Simple cartoon of a chromosome is often used in genomics to show the overalll structure of a chromosome
Describe and label a chromosome
Describe and label a chromosome
Mitosis
Cell to cell copies
Meiosis
Produces your sex cells “Ovaries and testes”
Gametes
Male spermatozoa and female ova
Describe the diagram
Describe the diagram
How do sex cells differ from other tissue type cells?
Sex cells are haploid cells— only containing one strand of DNA.
Stages of Mitosis
Prophase metaphase anaphase telephase
Chromosome pair
Chromosome pair
Genetic Variation
Genotype
Phenotype
Gtype
What the gene is for
Pheotype
How the gene is expressed (not always the same)
Punnett Square
Grid used to determine the probability of inheriting genetic tratis
What is a carrier of a genetic disease
A person who has a recessive (hidden gene) they do not have any symptoms of the disease but could pass the recessive (hidden) gene to their child

Examples: Hemophila, Duchenne Muscular Dystrophy Colorblindness

Examples of Genetic Disease
Sex-Linked
Single Gene Diseases
Chromosomal
Cystic Fibrosis
PKU
Hemophilia
Albinism
Chromosomal
Abnormal number of chromosomes

Non disjunctio-extra chromosome occurs

Example: Down Syndrome (trisomy 21- extra one)
Klinefelter Syndrome XXy
Turner Syndrome XO

Other examples of single cell diseases
Cystic Fibrosis- Thick mucous, one single gene for protein on cell membrane and one Chloride ion is altered, causes mucous to increase

PKU- More common in people descended from Western Europe; one single gene is missing. The gene that codes for one enzyme that digests phenylalanine. Amino acid is in most protein

Hemophilia- Group of blood-clotting disorders caused by a failure to form clotting factors VIII, IX, or XI

Albinism- Born with no skin, pigmentation, melanin in the skin and eyes, cannot go out in the sun.

Tay Sachs Syndrome- Test with a guthrie
One single gene for an enzyme involved in lipid digestion
Too many fatty compounds accumlate in the brain tissue . Can lay dormant for up to 7 months. Starts with muscle twitches, seizures, vision loss, hearing loss, fatal by the age of 4

Why is amniocentesis performed?
Can be chemically tested or used to produce a Karyotype of the developing baby

They draw out fluid from the skin cells.

What is gene therapy
the transplantation of normal genes into cells in place of missing or defective ones in order to correct genetic disorders.
Pedigree
A chart that illistrates genetic relationships in a family over several generations.
There are ________ of genes in humans?
20k-25k
About this percent of the DNA carries active genes.
2%
The shorter arm of the chromosome is the?

The longer arm of the chromosome from from the centromere is the?

p-arm

q-arm

Which of the following increases genetic variation in the offspring?
Independent assortment and crossing over
The normal skin pigment gene “A” is dominant to the recessive albino gene “a.” A person with genes Aa
Would have normal skin pigment and would be a carrier of albinism
Which of the following is not true about the X and Y chromosomes?
Not all sex-linked diseases are carried by the Y chromosome
example of a sex-linked condition.
red/green color blindness
The single-gene disease caused by recessive genes that fail to produce the enzyme phenylalanine hydroxylase is
phenylketonuria.
The most well-known chromosomal disorder is trisomy 21, which produces a group of symptoms called
Down Syndrome
A chart that illustrates genetic relationships in a family over several generations is called a
pedigree
The procedure in which fetal tissue can be collected from the fluid surrounding the fetus is called
Aminocentisis
Which of the following is not true of genetic mutations?
They are always harmful to the cell or individual
This is the science that describes how environmental factors may result in offspring with genetic traits that cannot be explained by genes alone
EpiGenetics
This is a single gene disease which causes an impairment of ion transport across the cell
membrane.
Cystic Fibrosis
This is a single gene recessive condition that involves the failure of an essential lipid processing enzyme, hexosaminidase.
Tay-Sach
This is an epigenetic condition caused by an over-methylation of a section of DNA
Fragile X Syndrome
This condition is caused by a male having an extra X chromosome, XXY.
Klinefelter Syndrome
This condition occurs in a female with a single X chromosome, XO.
Turner Syndrome
This is a grid that is used to determine the probability of inheriting a genetic trait.
Punnett Square
This can be used to detect chromosome disorders by studying photographs of chromosomes in the process of mitosis.
Karyotype
Categories: Genetics