Unit 1 - Definitions

Question 1

alleles

Answer 1

two or more alternate forms of a gene. The alleles are located at the same position on one of the pairs of homologous chromosomes

Question 2

heredity

Answer 2

passing down from older generations

Question 3

variation

Answer 3

change

Question 4

gene

Answer 4

a segment of the DNA that carries information codes for a particular trait

Question 5

locus

Answer 5

the location of a gene on a chromosome

Question 6

cloning

Answer 6

the process of forming identical off-spring from a single cell or tissue ``

Question 7

enucleated

Answer 7

the condition where a cell does not contain a nucleus

Question 8

totipotent

Answer 8

having the ability to support the development of an egg to an adult

Question 9

blastula

Answer 9

an embryoria stage consisting of a ball of cells produced by division following the fertilization of an egg

Question 10

centriole

Answer 10

cylindrical organelles that aid in the formation of spindle fibers

Question 11

spindle fibers

Answer 11

protein structures that guide chromosomes during cell divison

Question 12

homologous chromosomes

Answer 12

paired chromosomes similar in shape, size, gene arrangement, and gene information
- but different versions (blue vs green eyes)

Question 13

tetrad

Answer 13

a pair of homologous chromosomes, each with two chromatids

Question 14

cytokinesis

Answer 14

the division of cytoplasm

Question 15

gametes

Answer 15

sex cells that have a haploid chromosome number

Question 16

haploid

Answer 16

refers to the number of chromosomes in a gamete, n

Question 17

diploid

Answer 17

refers to twice the number of chromosomes in a gamete, every cell in the body except for sex cells contain a diploid chromosome number (2n)

Question 18

zygote

Answer 18

a cell resulting from the union of a male and a female sex cell until it divides, and then it is called an embryo
sperm + egg = zygote

Question 19

meiosis

Answer 19

two-stage cell division in which the chromosome number of the parental cell is reduced by half. Meiosis is the process by which gametes are formed

Question 20

mitosis

Answer 20

a type of cell division in which a daughter cell receives the same number of chromosomes as the parent cell

Question 21

terminal

Answer 21

cell dies

Question 22

non-terminal

Answer 22

cell lives

Question 23

non-disjunction

Answer 23

can occur in Anaphase I or II

- the chromosomes do not seperate & instead both move to the same pole of the cell

Question 24

trisomy

Answer 24

one pair is actually a triple

Question 25

montsomy

Answer 25

one pair is actually singular

Question 26

karyotype

Answer 26

organization of the chromosome

Question 27

down's syndrome

Answer 27

trisomy of 21

Question 28

edward's syndrome

Answer 28

trisomy of 18

Question 29

klinefelter syndrome

Answer 29

trisomy of 23

Question 30

turner

Answer 30

monosomy of 23

Question 31

triple X

Answer 31

trisomy of 23

Question 32

genotype

Answer 32

the allele combination HH Hh hh

Question 33

phenotype

Answer 33

the observed trait | - dominant or recessive

Question 34

test cross

Answer 34

performed to determine the genotype of a dominate phenotype; always between unknown genotype & homozygous recessive

Question 35

in breeding

Answer 35

mating with closely related individuals

Question 36

hydridization

Answer 36

two parents, each with a different desired phenotype

Question 37

complete dominace

Answer 37

one allele is dominant over the other

Question 38

incomplete dominace

Answer 38

neither allele is dominant over the other, they are blended together red, white - pink

Question 39

codominace

Answer 39

both alleles attempt to dominate the other but are unsuccessful; results in both phenotypes being expressed red, white - red & white

Question 40

autosomes

Answer 40

non-sex chromosomes

Question 41

somatic cells

Answer 41

all the cells of an organism other than the sex cells

Question 42

sex-linkage

Answer 42

occurs when the condition comes form a gene on the 23rd homologous pair

Question 43

dihybrid cross

Answer 43

a type of cross that involves two genes, each consisting of nonidentical alleles

Question 44

chromosomes

Answer 44

long threads of genetic material found in the nucleus of cells

Question 45

crossing over

Answer 45

the exchange of genetic material between two homologous chromosomes

Question 46

nucleus

Answer 46

the control center for the cell, which contains hereditary information. the nucleus is bound by a double membrane

Question 47

asexual reproduction

Answer 47

the production of offspring from a single parent; offspring inherit the genes of that parent only

Question 48

sexual reproduction

Answer 48

the production of offspring from the union of two sex cells, one from each different parent; the genetic makeup of the offspring is different from that of either parent

Question 49

synapsis

Answer 49

the pairing of homologous chromosomes