Genetics

Question 1

gregor mendel

Answer 1

bred garden peas, argued that parents pass on to their offspring discrete heritable factors, said genes retain their individuality generation after generation (don’t blend). true bred plants
hypotheses:
1. there are alternative versions of genes that account for variations in inherited characters, alternative versions of genes called alleles
2. for each character, an organism inherits two alleles, one from each parent. can be homogenous or heterozygous
3. if the two alleles of an inherited pair differ, then one determines the organism’s appearance and is called the dominant allele; the other has no noticeable effect on the organism’s appearance and is called the recessive allele
4. a sperm or egg carries only one allele for each inherited character because allele pairs separate (segregate) from each other during the production of gametes

Question 2

true-breeding

Answer 2

varieties of an organism for which self-fertilization produces offspring identical to the parent

Question 3

hybrid

Answer 3

the offspring of two different varieties of organism (ex. purple plant bred with white plant, offspring is hybrid)

Question 4

fertilization

Answer 4

the union of the nucleus of a sperm cell with the nucleus of an egg cell, producing a zygote. organisms fertilize one another to make more

Question 5

p generation

Answer 5

first generation, parents, true-breeding

Question 6

f1 generation

Answer 6

hybrid offspring of p generation

Question 7

f2 generation

Answer 7

when f1 plants self fertilize or fertilize one another, offspring are f2 generation

Question 8

monohybrid cross

Answer 8

when two parents are mated that only have one different character

Question 9

dihybrid cross

Answer 9

a mating of parental varieties differing in two characters

Question 10

gene

Answer 10

factors that parents pass on to their children. they remain individuality generation after generation. they determine certain characteristics of the children

Question 11

allele

Answer 11

the alternative versions of a gene. different alleles count for variations in inherited characteristics

Question 12

genotype

Answer 12

an organism’s genetic makeup (ex. Gg)

Question 13

phenotype

Answer 13

an organism’s expressed, or physical, traits (ex. white flowers)

Question 14

recessive

Answer 14

the allele that has no noticeable effect on the organism’s appearance. if a gene is recessive, it may skip generations. the only time it is expressed is it the person has two recessive alleles, lower case

Question 15

dominant

Answer 15

the allele that determines the organism’s appearance, upper case

Question 16

heterozygous

Answer 16

an organism that has two different alleles for a gene is heterozygous for that gene and is called a heterozygote

Question 17

homozygous

Answer 17

an organism that has two identical alleles for a gene is homozygous for that gene and is called a homozygote

Question 18

law of segregation

Answer 18

one of mendel’s laws. a sperm or egg carries only one allele for each inherited character because allele pairs separate (segregate) from each other during the production of gametes

Question 19

law of independent assortment

Answer 19

one of mendel’s, each pair of alleles segregates independently of other pairs of alleles during gamete formation

Question 20

gametes

Answer 20

a sex cell; a haploid egg or sperm. the union of two gametes of opposite sex produces a zygote

Question 21

locus

Answer 21

the particular site where a gene is found on a chromosome. homologous chromosomes have corresponding gene loci. alleles of a gene reside at the same locus on homologous chromosomes

Question 22

homologous chromosomes

Answer 22

homologues, chromosomes that carry genes controlling the same inherited characteristics. homologous chromosomes have genes for the same characters located at the same positions along their lengths

Question 23

amniocentesis

Answer 23

needle into uterus, take out fetus cells, allows for karyotyping

Question 24

CVS

Answer 24

chorionic villus sampling, biochemical testing

Question 25

mendelian genetics

Answer 25

explain inheritance in terms of discrete factors (genes) that are passed on along from generation to generation according to simple rules of probability. valid for all sexually producing organisms but often don’t cover it all

Question 26

non mendelian genetics

Answer 26

codominance, incomplete dominance, pleiotropy, polygenic

Question 27

incomplete dominance

Answer 27

when the appearance of f1 hybrids falls between the phenotypes of the two parental varieties (ex. red and white flowers make pink flowers. NOT BLENDING

Question 28

codominance

Answer 28

both alleles are expressed in heterozygous individuals (ex. blood types)

Question 29

pleiotropy

Answer 29

when genes influence multiple characters
SICKLE CELL ANEMIA
most genes

Question 30

polygenic inheritance

Answer 30

the additive effects of two or more genes on a single phenotypic character. converse of pleiotropy. multiple letters (ex. skin color = AABbcc

Question 31

linked genes

Answer 31

genes located close together on the same chromosome tend to be inherited together and are called linked genes. generally do not follow mender’s law of independent assortment
WEIRD RATIO = LINKED GENE

Question 32

chromosome theory of inheritance

Answer 32

cells undergoing meiosis. genes occupy specific loci on chromosomes and it is the chromosomes that undergo segregation and independent assortment during meiosis. thus, it is the behavior of chromosomes during meiosis and fertilization that accounts for inheritance patterns

Question 33

crossing over

Answer 33

recombines linked genes into mixtures of alleles not found in parents
chromosomes of offspring have combo that neither parent has
creates gamete diversity

Question 34

recombinants

Answer 34

recombinant gametes are gametes that are made from a recombination of parental genes (ex. by crossing over)

Question 35

sex chromosome

Answer 35

X and Y

Question 36

sex-linked traits

Answer 36

a gene located on either sex chromosome is a sex-linked gene. traits that are sex-linked are passed on with the sex chromosomes

Question 37

pedigree

Answer 37

a family tree representing the occurrence of heritable traits in parents and offspring across a number of generations

Question 38

autosomal recessive

Answer 38

not sex-linked, two copies of recessive gene given to child, skips generations

Question 39

autosomal dominant

Answer 39

not sex-linked, at least one dominant gene, stays generations

Question 40

chi-square

Answer 40

X^2 = Σ[(O-E)^2/E]

Take observed minus expected squared divided by expected and then add all those together