Chapter 4 & 5

Question 1

What is sex?
Gender?

Answer 1

• male/female
• person’s biological/anatomical sexual identity
• person’s socially defined sexual identity

Question 2

What is an example of a species where the environment determines the sex of their offspring?

Answer 2

many reptiles
- turtles

Question 3

Define genic?

Answer 3

alleles at autosomal loci

Question 4

Which chromosome has female-promoting genes?

Answer 4

X

Question 5

What has male promoting genes?

Answer 5

autosomes

Question 6

Does the Y chromosome determine the sex of an offspring?

Answer 6

No

Question 7

What is the use of the Y chromosome?

Answer 7

fertility in males

Question 8

What determines the sex of an offspring?

Answer 8

the ratio of chromosomes to autosomes

Question 9

What is the ratio of sex chromosomes (female) and autosomes (male)?

Answer 9

Female
- 1

Male
- 0.5

Question 10

If the sex chromosomes to autosome ratio is between 1 and 0.5, what is this called?

Answer 10

intersex

Question 11

What is the significane of the SRY gene?

Answer 11

any human with the SRY gene will be male

Question 12

How does the SRY gene indicate a male offspring?

Answer 12

• some gonad tissue produces male sex hormones
• gonads develop into testes
• hormones suppress the female duct and produce other male characteristics

Question 13

For females are both X chromosomes active?

Answer 13

no, only one

Question 14

Females:
What is it called when only on X chromosome is active?

Answer 14

Barr body

Question 15

What syndrom is diagnosed with X0 chromosomes?
What are the symptoms?

Answer 15

• Turner’s syndrome
• sterile femal
• some unnormal traits

Question 16

What syndrom is diagnosed with XXY (XXXY, XXXXY, XXYY) chromosomes?
What are the symptoms?

Answer 16

• Kleinfelter’s syndrome
• sterile male
• likely without full male development

Question 17

What syndrom is diagnosed with XXX (XXXX, XXXXX) chromosomes?
What are the symptoms?

Answer 17

• Triplo-X syndrome
• females may be sterile
• show little physical deviation from normal
• more X’s, more severe

Question 18

What syndrom is diagnosed with XYY chromosomes?
What are the symptoms?

Answer 18

normal

Question 19

What is the diagnosis of an intersex individual?

Answer 19

androgen insensitivity syndrome

Question 20

Why could females never have the SRY gene?

Answer 20

SRY gene could be harmful to female

Question 21

Where is the pseudo-autosomal regions located?

Answer 21

at the ends of the Y chromosome

Question 22

What sex linkage?

Answer 22

a locus is on one sex chromosomes, not the other

Question 23

What are the advantages of studying with fruit flies?

Answer 23

• short generations
• many offspring
• small
• only 4 pairs of chromosomes (8 total)

Question 24

How did Morgan’s experiment with fruit flies support the chromosomal theory of inheritance?

Answer 24

• sex was determined by sex chromosomes
  
  • genes must be on chromosomes
• eye color locus is on the X chromosome, not the Y chromosome

Question 25

What is a reciprocal cross?

Answer 25

cross the parents, then reverse the sexes - switch the genes from the mother to the father (vic versa), the cross

Question 26

What is complete dominance?

Answer 26

when phenotypes of the heterozygote and dominant homozygote are identical

Question 27

What ratio does Mendel's traits cause?

Answer 27

3:1

Question 28

Why is there complete dominance?

Answer 28

the recessive allele's function is negated

Question 29

Can complete dominance be qualitative, quantitative, or both?

Answer 29

only qualitative

Question 30

What are a couple diseases caused by recessive alleles?

Answer 30

- cystic fibrosis - Cl-transport protein

Question 31

What can increase the speed of enzymes?

Answer 31

- build up of substrate - a lower amount of product

Question 32

What is incomplete dominance?

Answer 32

when one allele is not completely dominant over the other

Question 33

What ratio dose incomplete dominance have? Genotype? Phenotype?

Answer 33

1:2:1

Question 34

What is codominance?

Answer 34

when both alleles contribute to the phenotype

Question 35

What is polydactyly?

Answer 35

extra fingers or toes

Question 36

What is penetrance?

Answer 36

% of individuals having a certain genotype that express an expected phenotype

Question 37

What is expressivity?

Answer 37

the degree to which a trait is expressed

Question 38

What are lethal alleles?

Answer 38

alleles that cause the death of the organism that carries them

Question 39

What is the phenotype ratio of lethal alleles?

Answer 39

2:1

Question 40

What is Huntington's disease in humans?

Answer 40

causes nerve cells (neurons) in parts of the brain to gradually break down and die

Question 41

What is a gene interation?

Answer 41

a single phenotype is determined by more than one locus

Question 42

What is an interaction with epistasis?

Answer 42

one epistatic locus masks or hides the effect of a second hypostatic locus

Question 43

What is epistatic?

Answer 43

interaction of genes at different loci

Question 44

What is hypostatic?

Answer 44

A gene that is affected by another gene

Question 45

What is recessive epistasis? What is its ratio?

Answer 45

- homozygous recessive condition at a locus that prevents the expression of phenotypes determined by a second locus - 9:3:4

Question 46

What is dominant epistasis? What is the ratio?

Answer 46

- dominant genotype on one gene inhibits expression of another gene - 12:3:1

Question 47

What is duplicative recessive epistasis? What is its ratio?

Answer 47

- homozygous recessive at either of two loci - 9:7

Question 48

What is complementation?

Answer 48

two parents with similar recessive phenotypes, whom produce offspring with a wild-type phenotype.

Question 49

What are sex-influenced characteristics?

Answer 49

- traits that are controlled by genes on autosomes - are expressed differently in males and females

Question 50

What are sex-limited characteristics?

Answer 50

autosomal genes whose expression is limited to one sex

Question 51

What is cytoplasmic inheritance?

Answer 51

transmission of genetic material independent of the nucleus

Question 52

What are some distinct characteristics of the mitochondria and chloroplast?

Answer 52

- small chromosomes - few genes - materially inherited in most species

Question 53

Multiple copies of chromosomes allow cells and individuals to be what?

Answer 53

chimeric (chimera)

Question 54

What is epigenetics?

Answer 54

the study of environmental influences on gene expression that occur without a DNA change

Question 55

What is DNA methylation? What can it do?

Answer 55

- the addition of methyl groups to certain bases in DNA - inhibit or completely turn off a gene

Question 56

define a histone?

Answer 56

any of a group of basic proteins found in chromatin.

Question 57

What is trans-generational epigenetics?

Answer 57

When parents transmit epigenetic changes in gene expression to their children.

Question 58

What is anticipation?

Answer 58

when highly unstable repeated sequences increase in number very rapidly

Question 59

What is the effect of anticipation?

Answer 59

mutations are fast enough to be visible within a single family

Question 60

What are environmental effects?

Answer 60

anything other than genetics

Question 61

What are continuous traits? What are they called?

Answer 61

- require measurements for description - quantitative characteristics

Question 62

What is polygenic?

Answer 62

A trait that is controlled by many genes

Question 63

What are multifactorial characteristics?

Answer 63

Characteristics influenced both by environmental and genetic factors.

Question 64

What is pleiotrophy?

Answer 64

When one gene affects other genes it is not related to