Chapter 8: Inheritance, Genes, and Chromosomes

Question 1

Blending Inheritance

Answer 1

gametes contained “hereditary derminants (genessss)” that blended
think inks of different colors
short and tall = medium
smooth seed and wrinkled seed = intdeterminate
this would create the loss of parental characteristics
not real anymore

Question 2

Particulate inheritance

Answer 2

when gametes fuse, each determinant was distinct and remained intact
wrinkled seeds and smooth seeds would have offspring with determinants for both

Question 3

character

Answer 3

an observable physical feature

ex. seed shape

Question 4

trait

Answer 4

a particular form of a character

ex. spherical or wrinkled seeds

Question 5

true-breeding

Answer 5

when crossed wrinkled with another wrinkled, all wrinkled

homozygous

Question 6

How did Mendel perform his experiments?

Answer 6

Step One: cut the stamen off one parental flower (why you may ask? so it can’t self-fertilize)
step two: fertilize it with pollen from another flower with contrasting chracters
step three: plant the seeds from this pairing and watch them grow (write down traits and how many)
optional step 4: The F1 plants (in step three) self-pollinate and see what happens

Question 7

Parental generation P

Answer 7

the truebreeding plants that mendel used in his experiment

Question 8

First filial generation F1

Answer 8

the first offspring generation in Mendel’s experiments

Question 9

Second Filial Generation F2

Answer 9

the second offspring generation in Mendel’s experiments

Question 10

hybrid

Answer 10

the offspring of crosses between organisms differing in one or more characters

Question 11

monohybrid

Answer 11

Mendel’s F1 generation
the offspring between parental varieties with contrasting traits for a single character
smooth v. wrinkled

Question 12

Dominant

Answer 12

the trait that “overpowers”

Question 13

Recessive

Answer 13

the trait that will only be expressed if the gene for the dominant trait is not present

Question 14

allele

Answer 14

different forms of a gene for particular characters

smooth seed allele vs wrinkled seed allele

Question 15

Homozygous

Answer 15

two alleles that are the same

ex. two alleles for wrinkled seeds

Question 16

Heterozygous

Answer 16

two alleles that are different

ex. one allele for wrinkled seedfs, another for smooth

Question 17

Phenotype

Answer 17

the physical appearance of an organism

Question 18

Genotype

Answer 18

genetic constitution of an organism

Question 19

Law of Segregation

Answer 19

Mendel

when any individual produces gametes, the two copies of a gene separate, so that each gamete receives only one copy

Question 20

Punnett square

Answer 20

with the blocks
grid
male gametes on top, female on the side

Question 21

How is the recessive gene suppressed?

Answer 21

it can become mutated so it doesn’t get transcribed and translated or encode a nonfunctinoal protein

Question 22

Test cross

Answer 22

used to determine whether or not someone showing a dominant trait is homozygous
this is done by crossing them with an individual who is homozygous recessive for the trait (which isn’t hard to identify becuase if they display the recessive phenotype then they are homozygous recessive)

Question 23

Dihybrid cross

Answer 23

cross between indiciduals that are identical double heterozygotes

ex. two heterozygous smooth and yellow plants
9: 3:3:1 ratio

Question 24

Law of Independent Assortment

Answer 24

Mendel

alleles of different genes assort independently of one another during gamete formation

Question 25

Basic conventions of probability

Answer 25

certain= probability of one impossible= probability of 0 everything else in between

Question 26

Pedigrees

Answer 26

family trees that show the occurence of inherited phenotypes in several generations of related individuals

Question 27

What are the key things to look for in a dominant pedigree?

Answer 27

``` every person with the abnormal phenotype has an affected parent either all (homozygous parent) or half (heterozygous parent) or the children in an affected family are affected ```

Question 28

What are the key things to look for in a recessive pedigree?

Answer 28

Affected people often have two unaffected parents | about one fourth of children of unaffected parents in affected families are affected

Question 29

Mutations

Answer 29

rare, stable, and inherited changes in the genetic material

Question 30

True or false: an allele can mutate to become a different allele

Answer 30

true

Question 31

What affects the prevalence of a new allele?

Answer 31

the fitness of the individuals carrying it

Question 32

wild type

Answer 32

THE ALLELE THAT IS PRESENT in most of the individuals in nature

Question 33

Mutant alleles

Answer 33

the not wild type

Question 34

Polymorphic

Answer 34

a gene with a wild type allele that is present less than 90% of the time

Question 35

Incomplete dominance

Answer 35

alleles are not dominant or recessive to one another heterozygotes have intermediate phenotypes red and white makes pink

Question 36

Codominance

Answer 36

two alleles of a gene both produce phenotype when present in a heterozygote ex. AB blood type

Question 37

Epistasis

Answer 37

the phenotypic expression of one gene is affected by another ex. labsssss (such cuties) Ee or EE other gene is good to go ee, other alleles turned off

Question 38

Hybrid vigor (heterosis)

Answer 38

Darwin- corn offspring produced by different genetic barieties are tall Shull- they are also heavier

Question 39

Quantitative traits

Answer 39

traits conferred by multiple genes | must be measured, not assesed qualitatively

Question 40

True or false: most complex phenotypes are determined by multiple genes

Answer 40

true

Question 41

True or false: the phenotype of an indivdual results from its genotype alone

Answer 41

falsee | genotype and environment interact to create phenotype

Question 42

Penetrance

Answer 42

the proportion of individuals in a group with a given genotype that actually show the expected phenotype helps describe the eggects of genes and enviro on phenotype ex. not everyone with the mutant BRCA1 develops breast cancer--> incompletely penetrant mutation

Question 43

Expressivity

Answer 43

degree to which a genotype is expressed in an individual ex. one person with BRCA1 may have breast and ovarian cancer, another just breast cancer, so it has variable expressivity

Question 44

locus

Answer 44

a particular site on a chromosome where a particular sequence of DNA (gene) resides

Question 45

`Thomas Hunt Morgan

Answer 45

gene linkage Columbia University Fruit fly experiments

Question 46

Morgan Experiments with fruit flies

Answer 46

he did a test cross with two known genes B and Vg for wing shape and body color expected 1:1:1:1 of different phenotypes often the two traits were inherited together loci linked on same chromosome crossing over makes the coupled inheritance not absolute

Question 47

recombination frequency

Answer 47

the number of recombinant progeny divided by the total number of progeny greater for loci that are father apart on a chromosome, which means they

Question 48

genetic linkage

Answer 48

association between genes on a chromosome so that they do not exhibit random assortment and only rarely recombine the closer they are, the lower the frequency of recombination

Question 49

autosomes

Answer 49

regular chromsomes (these pairs are similar in size to one another)

Question 50

sex chromsomes

Answer 50

determine the sex of an individual

Question 51

What are two differences between x and y chromsomes?

Answer 51

size | more genes are present on the x than the y

Question 52

hemizygous

Answer 52

a gene that is present as a single copy in a diploid organism

Question 53

sex-linked inheritance

Answer 53

inheritance of a gene that is carried on a sex chromosome

Question 54

patterns of sex0linked recessive phenotypes

Answer 54

appears a lot more in males than females (men only need one copy) men can only pass mutation to daughters (sons get the y chromosome) daughters with one x linked mutation are heterozygous carriers mutant phenotypes can skip a generation if it passes from father to daughter to son

Question 55

Heterozygous carriers

Answer 55

phenotypically wild type, but can pass on mutant allele to children

Question 56

True or false: the only organelle with genetic material in the cell is the nucleus

Answer 56

false | mitochondria and plastids

Question 57

True or false: the inheritance of organelle genes differs from that of nuclear genes

Answer 57

true | mitochondria and plastids only inherited from mother (sperm only bring nucleus to fuse, no organelles)

Question 58

Cytoplasmic inheritance

Answer 58

the inheritance of organelles and genes | come from maternal cytoplasm

Question 59

True or false: prokaryotes can transfer genes from one to the other

Answer 59

truee

Question 60

Bacterial conjugation

Answer 60

happens via physical contact initiated by the sex pilus material then passes through a conjugation tube (JUST ONE WAY FROM DONOR TO RECIPIENT) once inside, it can recombine donor DNA can line up beside homolgous genes and cross over genes from donor can be integrated and change the recipients genetics only about hald of transfered genes become integrated, the integrated ones are passed on

Question 61

sex pilus

Answer 61

extends from the donor prokaryotic cell to the recepient prokaryotic cell, initiating contact and gene transfer

Question 62

Plasmids

Answer 62

smaller, circular DNA in bacteria have a few dozen genes tops generally these genes are for: unusual metabolic abilities (like breaking down hydrocarbons) antibiotic resistance (plasmids with these are R factors and are really dangerous)

Question 63

True or false: plasmids transfer genes between bacteria

Answer 63

true they can move between cells during conjugation don't need to recombine with main chromsome because they copy separately