Chapter 12 (bioquest 13?)

Question 1

Thomas Hunt Morgan

Answer 1

Did early genetic work- used Drosophilia melanogaster (fruit flies). Fruit flies have 4 pairs of chromosomes. 3 were the same in both males and females. for the fourth- female had XX but males had XY

Question 2

sex chromosomes

Answer 2

chromosomes that determine the sex of organism

Question 3

autosomes

Answer 3

remaining chromosomes that don’t determine sex of organism

Question 4

Sex determination

Answer 4

determined by the Y chromosome. Y has a specific region called SRY (sex determining region y)

Question 5

SRY (sex determining region y)

Answer 5

this region codes for a specific protien that stimulates gonads to produce/develop testes. (X chromosomes dont have a SRY region- therefore the gonads produce ovaries)

Question 6

Sex-linked traits

Answer 6

a trait taht is coded for by an allele on a sex chromosome

Question 7

Linked genes

Answer 7

pairs of genes that tend to be inherited together- a mixture is due to crossing over

Question 8

chromosome mapping

Answer 8

developed by geneticists to determine where specific genes are located- for treatment of various diseases

Question 9

germ cell mutation

Answer 9

afffects the gametes and the offspring (not the organism itself though)

Question 10

Somatic mutation

Answer 10

takes place in the body cells - affects the organism- not inherited

Question 11

Lethal mutations

Answer 11

cause death to organism

Question 12

chromosome mutations (4 types)

Answer 12

deletion, inversion, translocation, nondisjunction

Question 13

deletion (chromosome mutation)

Answer 13

loss of a piece of the chromosome

Question 14

inversion

Answer 14

1 section of chromosome breaks off and re-attaches backward

Question 15

translocation

Answer 15

piece of 1 chromosome breaks off and reattaches to a different (non homologous) chromosome

Question 16

nondisjunction

Answer 16

a chromosome fails to separate from homologue during meiosis- 1 gamete receives an extra copy of a chromosome, and the other receives none. (ie. down syndrome)

Question 17

Gene mutations

Answer 17

affects specifically: genes

point mutation: substitution, deletion mutation, insertion mutation, frameshift mutation

Question 18

point mutation

Answer 18

affects a single nucleotide (single letter) -the substitution, addition or removal of one

Question 19

substitution

Answer 19

1 nucleotide replaces another

Question 20

insertion mutation

Answer 20

nucleotide added - can cause frameshift mutation

Question 21

deletion mutation (gene mutations)

Answer 21

nucleotide removed- can cause frameshift mutation

Question 22

frameshift mutation

Answer 22

all the amino acids are all wrong

Question 23

pedigree

Answer 23

diagram that shows how a trait is inherited over several generations (family tree that traces how trait is inherited)

Question 24

patterns of inheritance

Answer 24

• most diseases tend to be recessive

- carriers: have 1 copy of the recessive allele but do not have the disease

Question 25

genetic traits and disorders

Answer 25

diseases that affect genetic characteristics

Question 26

polygenic inheritance

Answer 26

characteristics that are influenced by several genes (ie. height, skin color, eye color, hair color)

Question 27

complex characteristics

Answer 27

characters that are influenced by genes and the environment as well (ie. heart disease, diabetes, skin color)

Question 28

multiple alleles

Answer 28

genes with 3 or more alleles

Question 29

gene

Answer 29

1 portion fo chromosome that controls a single trait

Question 30

allele

Answer 30

one of the alternate forms of a gene

Question 31

co-dominance

Answer 31

both alleles will be expressed equally

Question 32

incomplete dominance

Answer 32

blended trait (ie. red + white = pink)

Question 33

X linked traits

Answer 33

carried on the X chromosome (determined by the X)

Question 34

sex influenced traits

Answer 34

these are usually autosomal, complex traits (ie. male pattern baldness)

Question 35

single allele traits

Answer 35

autosomal dominant: huntington’s disease

Question 36

detecting genetic diseases

Answer 36

amniocentesis, chorionic villi

Question 37

amniocentesis

Answer 37

testic amniotic fluid at about 14-16 weeks. Covers about 200 disorders

Question 38

chorionic villi

Answer 38

testing of chorionic villi cells that grow between uterus and placenta (covers about 400 diseases) 8-10 weeks (more chance of miscarriage)

Question 39

Huntington’s disease

Answer 39

30-40 years of age: forgetfullness and irritablilty

Question 40

Sickle cell

Answer 40

red blood cells chance shape- recessive chromosome 11

Question 41

hemophilia

Answer 41

factor 8 missing, on x chromosome

blood clotting disorder (blood won’t clot)

Question 42

downs

Answer 42

extra chromosome #21 (during meiosis they dont separate correctly)

Question 43

genetic counseling

Answer 43

person who talks to you about genetic disorders

Question 44

gene therapy

Answer 44

technique that replaces the “bad copy” of the gene with a healthy one