Biology Ch 9

Front 1

Gene

Back 1

Sequence of DNA that codes for a trait

Front 2

Allele

Back 2

gene form

Front 3

Dominant

Back 3

gene that will get expressed; determines the organism's appearance

Front 4

Recessive

Back 4

gene that will only be expressed if a dominant allele is not present; have no noticeable affect on the organism's appearance

Front 5

Homozygous

Back 5

both alleles are the same (AA) or (aa)

Front 6

Heterozygous

Back 6

alleles are different (Aa)

Front 7

Genotype

Back 7

the types of genes you have, genetic makeup (ie All Tt)

Front 8

Phenotype

Back 8

observable or expressed traits (ie All Tall)

Front 9

Wild type

Back 9

phenotype most commonly found in nature, most common type

Front 10

True breeding

Back 10

organism for which sexual reproduciton prodcues offspring with inherited traits identical to those of the parents; the organisms are homozygous for the characteristics under consideration

Front 11

hybrid

Back 11

the offspring of parents of two different species or or two different varieties of one species; the offspring of two parents that differ in one or more inherited traits; an individual is heterozygous for one or more pairs of genes

Front 12

monohybrid cross- p156

Back 12

a genetic cross with one trait, mating of organisms idffering at one genetic locus

Front 13

(Mendel's) Law of segregation- p 156 & 171

Back 13

(Mendel's first law of inheritance)
Individuals have two alleles for each gene, and when gametes form by meiosis, the two alleles separate, and each resulting gamete ends up with only one allele of each gene

Front 14

Homologous

Back 14

two chromosomes ( 1 mom, 1 dad) that make up a matched pair in a diploid cell. They are of the same length, centromere position, and staining pattern, & possess alleles for the same genes at the corresponding loci.

Front 15

Law of independent assortment
p158 & 171

Back 15

(Mendel's second law of inheritance)
alleles of a pair segregate independently of other allele pairs during gamete formation

Front 16

Rule of multiplication- p 160
(look @ Q on p160)

Back 16

Calculates the probability of TWO independent events...The probability of a compound event is the product of the separate probabilities of the independent events. (ie two coins tossed-1/2x1/2=1/4)

Front 17

Testcross (dogs-p 159)

Back 17

The mating between an individual of unknown genotype for a particular characteristic and an individual that is homozygous recessive (bb) for that same characteristic

Front 18

The rule of addition
P 160

Back 18

Calculates the probability of an event that can can occur in different ways. (Tt +Tt=1/4+1/4=1/2)

Front 19

Autosomal Disorders

Back 19

Disorders controlled by a single gene located on autosomes (not the x or y chromosome). Recessive & Dominant disorders fall under this category.

Front 20

Recessive disorder

Back 20

Most common type of human genetic disorders. Most common is cystic fibrosis. Other examples include: albinism, galactosemia, PKU, sickle-cell anemia, Tay-
Sachs

Front 21

Dominant Disorder

Back 21

Disorder due to dominant alleles. Examples include extra fingers/toes, webbed fingers/toes, achondrolasia (dwarfism), alzheimer's, huntington's, and hypercholesterolemia

Front 22

Inbreeding

Back 22

Mating of close relatives that increases the probability of recessive homozygous traits, Especially prevalent with dogs, where hips, eyes, and behavior are at risk. Also, can increase the risk for still births, birth defects.

Front 23

Fetal /ultrasound imaging

Back 23

Using sound waves to produce a picture of the fetus.Sound waves bounce off the fetus. This technique is non-invasive; no known risk

Front 24

Fetoscopy

Back 24

procedure where a needle-thin tube with viewing scope/fiber optics is inserted into the utuerus

Front 25

Amniocentesis

Back 25

Procedure taken after 14-16 wks of pregnancy. needle is inserted into the abdomen that takes 10 ml (2 tsp) of amnio fluid out of the uterus. Bio chemical Tests on the fetal cells in the fluid are done immediately, as well as a few wks out. 1% chance for maternal bleeding, miscarriage, or preemie birth.

Front 26

Chorionic Villus Sampling (CVS)

Back 26

A procedure performed during pregnancy where a suction tube is inserted thru the cervix that takes tissue (fetal cells) from the chorionic villi. The fetal cells are then tested within hrs,with results within days

Front 27

Incomplete dominance p 166

Back 27

Type of inheritance where the phenotype (appearance) is intermediate of a zygote (Aa) is intermediate between the phenotypes of 2 homozygotes (AA & aa). ie pink and red flower yield pink flower. normal cholesterol, high cholesterol yield moderate cholesterol.

Front 28

Codominant p 167

Back 28

Inheritance pattern where a heterozygote expresses the distinct trait of both alleles (ie blood type)

Front 29

Pleiotropy p 168

Back 29

A single gene may affect phenotype in many ways/May affect several characteristics. ie Sickle cell Disease-lots of symptoms, multiple organs affected. The direct opposite of Polygenetic Inheritance.

Front 30

Polygenetic Inheritance p 169

Back 30

Additive effects of 2 or more gene loci on a single phenotypic characteristic. ie assume that skin color is controlled by 3 genes that are inherited differently (dark skin gene, medium skin gene, light skin gene)

Front 31

Chromosomal Basis or Theory of Inheritance p 171

Back 31

Theory stating that genes occupy specific loci (positions) on chromosomes that undergo segregation and independent assortment during meiosis. Thus it is the BEHAVIOR of the chromosomes during meiosis & fertilization that account for inheritance patterns.

Front 32

Linked genes p 172

Back 32

Genes located on the same chromosome that tend to be inherited together because they reside close together on the same chromosome. These genes generally DON'T follow Mendell's Law of Independent Assortment. ie purple flower and pollen shape don't follow 9:3:3:1 ratio

Front 33

Crossing over 173

Back 33

Process between two homologues during meiosis where new combinations of alleles are formed. It can separate linked alleles and produce gametes with recombinant chromosomes
ie AB & ab cross over and recombinant Ab & Ba gametes are produced

Front 34

Recombination frequency

Back 34

(When looking at two characteristics) The number of recombinant offspring (progeny)divided by the total number of offpsring/progeny.
Can also be used to map the relative positions of genes on chromosomes.

Front 35

Recombinant progeny

Back 35

Progeny (from mating) that carry combinations of alleles different from those in either of the parents as a result of independent assortment of chromosomes or crossing over.
ie Parents Ab & Bb result in Ab and Ba.

Front 36

Autosome

Back 36

A chromosome NOT directly involved in determining the sex of an organism; in mammals, for example, any chromosome other than X or Y.

Front 37

Male Chromosomes

Back 37

X and Y chromosomes

Front 38

Female Chromosomes

Back 38

XX chromosomes

Front 39

Gamete

Back 39

A sex cell; a haploid egg or sperm. Contains 1 sex chromosome and a haploid set of 22 autosomes
The union of two from opposite genders produces a zygote.

Front 40

Sex-linked gene

Back 40

A gene located on a sex chromosome..BE AWARE-sex chromosomes ALSO carry genes unrelated to sex

NOT to be confused with LINKED GENE