Chapter 24 Flashcards Preview

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Flashcards in Chapter 24 Deck (67):
0

Name 3 things true of chromosomes

Contain DNA
Coated with histones
46 mitotic cells

Chromosomes become visible only when they are condensed during active division, they r comprised of DNA molecules coated with histone protiens

1

The genes for cystic fibrosis are located on chromosome number

7

Cystic fibrosis is a hereditary disease that causes scar tissue to form in several organs, from nucleotide positioning techniques, it has been correlated with chromosome 7

2

Huntington disease is associated with chromosome

4

Huntington's disease is a neurological condition with seizures and psychological alterations, associated with chromosome number 4

3

When does the chromosome number reach 92

Before prophase

4

What term refers to the inheritance of traits that require 2 genes

Recessive

5

When a physician questions a patient about their family history, they are gathering evidence to construct a

Pedigree

6

How is familial hypercholesterolemia usually inherited

Incomplete dominance

High blood cholesterol has been linked to defective LDL liver receptors, inherited by incomplete dominance

7

Diseases that display different symptoms and signs for the same disease are displaying

Pleiotropy

Heterogeneity refers to the expression of a phenotype by many different genes

8

The the SRY gene causes expression of ? Chromosome gene

X

The sex determining gene on the Y chromosome causes expression of traits for sex on the X

9

What is an example of a codominant trait in humans

ABO blood groups

Codominance means that both alleles can be expressed. As in the blood type AB

10

Traits that are controlled by one or more genes and influenced by the influence by the environment are said to be

Multifactorial

When both genes and environment play a role in a trait it has many factors

11

The fact that a woman cannot generally grow a beard is because beard growth is a ? Trait

Sex-limited

Sex-limited traits occur in certain sexes, usually due to hormonal influence

12

The normal chromosome number is referred to as

Euploid

Eu means normal

13

The last pair of 23 chromosomes is referred to as the

Sex chromosomes

The 23rd pair of chromosomes is the X and/or Y chromosomes

14

Which chromosomes indicate a normal male fetus

XY

A normal male is XY. XX is female

15

Persons with dark skin who produce offspring with the same color have genes that are probably

Homozygous for melanin enzymes

Homozygous alleles are pairs of genes on two chromosomes, one from each parent, that contain the same information for a specific protein synthesis

16

Name 3 organ systems significantly affected by cystic fibrosis

Pulmonary
Gastrointestinal
Reproductive

17

Sickle cell genes are present in ?% of the American population with Central African ancestry

8%

About 8% of Americans with Central Africa ancestry have the sickle cell anemia gene but only 1 out of every 170 children develop sickle cell anemia

18

When will a person with sickle cell trait develop symptoms

Under hypoxia

During times when the oxygen tension is low, the red blood cells may sickle and distort, blocking capillaries, exercise may not be a sufficient provocation

19

The genes for the ABO blood types are

Codominant

The genes for the ABO blood antigens are co-dominant and appear on multiple allele chromosome position

20

Persons with blood type B have the ? Agglutinogens (antigen)

B

Since the ABO blood types are inherited as co-dominants, a person with phenotype B must have only agglutinogen (antigens) B on their erythrocyte membranes

21

What blood type could these parents NOT produce in their children, AO and BB

O

22

The final height of a child is determined by

Polygenic inheritance

The height of individuals or variations in skin tone is inherited in a polygenic pattern with many genes involved in complex arrangements, a child can be quite different from their parents

23

Name 3 things that affect the expression in an individual with a homozygous recessive trait

The health of the mother
Disease in the father
Diet

The expression of genes is an interaction among gene DNA potentials and the ability to allow development of traits, given the influence of environmental factors such as diet or health.

24

The result of meiosis is to produce

23 chromosomes

25

Traits only transferred from fathers to their sons are associated with the ? Chromosome

Y

Traits on the X chromosome may be given to males or females

26

What condition is NOT usually found in females

Duchenne dystrophy

27

The growth of facial hair is an example of

Sex-limited trait expression

28

What is the probability of there being a recessive gene in the gametes from a parents who is Aa (assuming a is recessive)

50%

If the parent cells contain the Aa genome, it is assumed that the genes will separate and assort randomly as A or a resulting in a 50% distribution

29

What offspring result from Aa and aa parents

Aa, Aa, aa, aa

If it is assumed that the genes separate with equal probability, then 2 of each Aa and aa must result

30

The inheritance of maleness is caused by a ? Chromosome pattern

XY

Chromosome pair number 23 is associated with sex determination while the other 22 are autosomal and code other factors, XX would be the karyotype for a female and XY is male

31

Which type of condition can only be passed from the father to his sons

Holandric

Sex-linked recessive traits are passed by the mothers to her sons.

32

Name 3 X-linked recessive conditions

Hemophilia A
Color Blindness
Optic atrophy

33

The condition ? Is characterized by a deficiency of plasma thromboplastin component (factor IX)

Hemophilia B

34

What term is correctly used to describe all Down's people?

Aneuploidy

Down's syndrome is an aneuploidy or abnormal chromosome pattern

35

The term for prenatal genetic testing sloughed-off fetal cells is called

Amniocentesis

36

Name 3 conditions are usually seen in Down's syndrome

Kidney defects
Heart defects
Mental retardation

37

How many genes are believed to constitute the human genome

40,000

38

During which meiosis division is the number of chromosomes halved

During meiosis I

39

Name a recessive human trait

Hairless forearms

40

Name 3 things that contribute to increasing genetic variability

Meiosis
Cross-over
Having children with someone who is not a relative

41

Several variant forms of a gene for a given trait are called

Alleles

42

A person who can pass either a widow's peak or straight hairline to the next generation is said to be ? For the hairline trait

Heterozygous

43

If a recessive trait, such as hemophilia, occurs more often in males than in females, it is because the gene for the trait is most likely carried on

The X chromosome

44

If a child contain a genes that is not found in either parent, then one of them is not the biological parent

T or F

True

Gene identification techniques are sufficiently precise at this time to prove that someone is not a parent beyond a reasonable doubt

45

Traits such as skin pigment are totally governed by inheritance

T or F

False

Environmental factors influence the expression of genes such as the effect of sunlight on dispersion of melanin and darkness of the skin

46

Gene therapy has not been completely successful at this time

T or F

True

Although medical research is making great progress, no disease has been cured by genetic replacement at this printing

47

All forms of gene therapy changes cannot be inherited

T or F

True

Some theoretical applications of gene therapy will involve fundamental changes in the genome at the level of the zygote

48


Fetal stem cells have no value over bone marrow in gene therapy research

T or F

False

Fetal cells have tremendous value because of their multipotential capabilities

49

A younger women has a higher risk of a Down's conception than one who is older

T or F

False

The greater the women's age, the higher the risk for having a baby with Down's

50

Chorionic villus sampling is less invasive than amniocentesis

T or F

False

Chorionic villus sampling carries a higher risk of miscarriage

51

Gene therapy using the liver can be used to prevent heart disease

T or F

True

Gene's can be inserted for Person's lacking LDL receptors in the liver thereby reducing the risk of LDL-induced coronary artery cholesterol plaque formation

52

Viruses are the usual cause of brain tumors such as gliomas

T or F

False

Actually viruses can be theoretically inserted in brain glioma tumors as a treatment

53

The phenomenon of incomplete dominance will result in the meiosis of cells with two forms of a particular gene

T or F

True

Incomplete dominance occurs when a particular gene such as for hemoglobin, has two distinct allele forms in which each pair may be homozygous or Herterozygous

54

Males always determine the sex of a fetus

T or F

True

Only the sperm cells contain either a Y or X chromosome, the oocytes are all X

55

A male with color blindness cannot have a daughter who is color blind because it is a X linked recessive

T or F

False

Mainly males exhibit x linked disorders because their single x gene cannot be masked by another x, therefore making the recessive x appeardominant, a female who is homozygous for color blindness gene will express the trait, although it is rare

56

It is possible for human cells to have more than 46 chromosomes

T or F

True

Because of the phenomenon of non-disjunction and other abnormal processes, many individuals 48 or more chromosomes such ad a XXYY pattern

57

The disintegration of chromosomes during meiosis is called nondisjunction

T or F

False

Nondisjunction is when chromosomes remain attached at the centromere

58

Older women carry a greater chance of having a child with trisomy 21 than a younger mother

T or F

True

Facts show that the risk of trisomy 21 increase dramatically with maternal age

59

Persons with Turner's syndrome have male chromosomes but have a female appearance

T or F

False

Turner's syndrome is having only one sex chromosome, the X

60

Only the sperm have the ability to determine the sex of the offspring

T or F

True

The egg always contributes an X chromosome

61

All genetic abnormalities are inherited

T or F

False

Mutations can occur during a lifetime

62

Sex-linked genes are those associated with chromosomes X or Y

T or F

True

Sex-limited means coming from the X or Y chromosome

63

Males and females have equal chances of inheriting X-linked disorders

T or F

False

Males are at higher risk of X linked disorders because they only receive one X chromosome

64

All Preston's with Down's syndrome display profound mental retardation

T or F

False

Not all people with Down's syndrome are retarded, some display perfectly normal or even higher intelligence

65

The genes of an individual will always be different from those of the parents

T or F

True

Since there are random variations in the DNA base sequences, the offspring resemble but are always slightly unique because of these new combinations and interactions with the environment

66

All birth defects are genetic and inherited

T or F

False

Birth defects are caused by teratogens from the environment