Lesson #2

Question 1

23rd pair of chromosomes:

Answer 1

Sex chromosomes.

Question 2

1st-22nd chromosomes:

Answer 2

Autosomes.

Question 3

Meiosis:

Answer 3

Sexual reproduction, produces 4 haploid gametes (Sperm or eggs) - These are genetically unique due to crossing over and independent assortment.

Question 4

Mitosis:

Answer 4

Produces genetically identical, diploid, cells.

Question 5

Genotype:

Answer 5

Genetic coding for a specific trait.

Question 6

Gene nomenclature in mice and rats:

Answer 6

Gene symbol - Sox2 (in italics)
Protein designation - SOX2

Question 7

Gene nomenclature in humans, primates, and domestic species:

Answer 7

Gene symbol - SOX2 (in italics)
Protein designation - SOX2 (not in italics)

Question 8

The short arm of chromosome:

Answer 8

P arm.

Question 9

The long arm of chromosome:

Answer 9

Q arm.

Question 10

Polygenic traits:

Answer 10

multiple genes located on more than one chromosome contributing to 1 trait - eye color/skin tone.

Question 11

The additive effects of many abnormal genes and environmental factors, that will be passed down in families?

Answer 11

Multifactorial events.

Question 12

Examples of multifactorial events:

Answer 12

Obesity, hypertension, atherosclerosis, and diabetes.

Question 13

What can occur from a single gene or a chromosomal defect?

Answer 13

Genetic disorders.

Question 14

This may occur spontaneously or due to toxic substances - such as radiation, chemicals, etc.

Answer 14

Genetic mutations.

Question 15

True or false - Single gene mutations in both autosomes and sex chromosomes are spread to offspring?

Answer 15

FALSE - single gene mutations are passed down in sex chromosomes, but not in autosomes.

Question 16

Mendelian traits are caused by:

Answer 16

Inheritance of defective alleles - either 1 (dominant) or 2 (recessive) alleles.

Question 17

True or false - X-linked dominant and recessive genes are examples of non-mendelian inheritance.

Answer 17

True!

Question 18

_______ ________ ________ normally affect structural proteins and receptors.

Answer 18

Autosomal dominant mutations.

Question 19

_________ ________ _________ normally cause defective enzymes.

Answer 19

Autosomal recessive mutations.

Question 20

True or false - Sex-linked recessive genes are most commonly expressed in men because they only have one X and do not need two alleles.

Answer 20

True!

Question 21

The process that inactivates one X chromosome in women, for gene dosage compensation, is called:

Answer 21

X-Inactivation.

Question 22

When does X-Inactivation occur? What pattern does it follow?

Answer 22

X-Inactivation occurs in the early blastocyst stage, and will replicate that X gene via mitosis to create a mosaic pattern.

Question 23

What amount of genes will escape X-Inactivation?

Answer 23

1/4 of genes on an inactive X will escape.

Question 24

What syndrome is due to an overdose of escaped genes in X-inactivation? What sex chromosomes would it have?

Answer 24

1. Klinefelter syndrome.
2. XXY

Question 25

What syndrome is due to a lack of escaped genes in X-Inactivation? What sex chromosomes would it have?

Answer 25

1. Turner syndrome. 2. X.

Question 26

___-______________ is due to an unequal separation of chromosomes in meiosis 1, giving either 22 or 24 chromosomes in gametes.

Answer 26

Non-disjunction, a chromosomal abnormality.

Question 27

Non-disjunction will occur when?

Answer 27

During mitotic divisions in early embryonic phase - causing mosaicism.

Question 28

What is the name for an interchange of chromosome parts between 2 or more non-homologous chromosomes?

Answer 28

Translocation, a chromosomal abnormality.

Question 29

The 2 types of translocation - Describe them:

Answer 29

1. Reciprocal - Some chromosomes will receive extra copies, while others will receive fewer copies than normal. No chromosome parts are lost. 2. Non-reciprocal - also called robertsonian translocations. When the long arms of a chromosome become bound to a common centromere, and the short arms of the chromosome are lost.

Question 30

Chromosomes for klinefelters syndrome?

Answer 30

XXY

Question 31

Chromosomes for turner's syndrome?

Answer 31

X

Question 32

Lethal chromosomes?

Answer 32

Y

Question 33

Down syndrome chromosomes:

Answer 33

47 chromosomes, trisomy 21.

Question 34

Patau syndrome chromosomes:

Answer 34

47 chromosomes, trisomy 13.

Question 35

Edwards syndrome chromosomes:

Answer 35

47 chromosomes, trisomy 18.

Question 36

Which two trisomies are due to robertsonian translocations?

Answer 36

Trisomy 21 and trisomy 13 (downs and patau)

Question 37

True or false? 60-70% of spontaneous abortions in the first trimester are due to some form of trisomy?

Answer 37

FALSE - Only 40-50% of spontaneous abortion in the first trimester is due to trisomy.

Question 38

What products do we get from non-disjunction in meiosis 1?

Answer 38

2 diploid gametes and 2 gametes with no chromosomes - All 4 SHOULD be haploid.

Question 39

What products do we get from non-disjunction in meiosis 2?

Answer 39

2 normal haploid gametes, 1 diploid gamete, and one gamete with no chromosomes - All 4 SHOULD be haploid.

Question 40

__________ __________ is caused by a balanced chromosomal translocation of the telomeric portion of chromosome 22Q and chromosome 9Q, and vice versa.

Answer 40

Philidelphia chromosome.

Question 41

True or false - The translocated fragment on a Philadelphia chromosome is non-functional.

Answer 41

FALSE - The translocated fragment of a Philidelphia chromosome IS functional.

Question 42

What type of translocation disorder occurs when the mother of the affected child has 45 chromosomes, where the long arms of chromosomes 21 and 14 translocate?

Answer 42

Translocation down syndrome - an example of a robertsonian translocation.

Question 43

What does the philidelphia chromosome produce?

Answer 43

Philidelphia chromosome produces a strong tyrosine kinase that causes malignant transformation. BAD!

Question 44

Mitochondria:

Answer 44

1. Arise by division of pre-exisiting mitochondria. 2. Has it's own it's own genetic machinary. 3. Has some functional mDNA proteins, but mostly utilizes nDNA.

Question 45

True or false: Homoplasmy is where mitochondria are inherited in a mixture of normal and mutant.

Answer 45

FALSE - Homoplamsy is when mitochondria are inherited either entirely mutant or entirely normal.

Question 46

____________ is when daughter cells receive a mixture of mutant and normal mitochondria.

Answer 46

Heteroplasmy.

Question 47

_______ pass down mitochondrial DNA, but ________ offspring are affected

Answer 47

Female, all.

Question 48

If a cardiac glycoside does not become resolved, it can cause damage to the mitochondria - this is called:

Answer 48

Calcium overload: