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Flashcards in Unit 3 Deck (37)
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1
Q

Karyotype

A

an ordered display of the pairs of chromosomes from a cell

2
Q

Homologous chromosomes

A

2 chromosomes in each pair, same shape and same genes

3
Q

Diploid cell

A

has 2 sets of chromosomes (2n). Normal eukaryotic organism. Humans have 46

4
Q

Haploid cell

A

half the number of chromosomes

5
Q

Gamete

A

(sperm or egg) contains a single set of chromosomes and is thus a haploid cell. Only type of human cells produced by meiosis, rather than mitosis

6
Q

Zygote

A

Fertilized egg

7
Q

Meiosis 1

A

Separates homologous chromosomes

8
Q

Meiosis 2

A

Separates sister chromatids

9
Q

Meiosis

A

reduces the number of chromosome sets from two (diploid) to one (haploid), producing cells that differ genetically from each other and from the parent cell

10
Q

Mitosis

A

conserves the number of chromosome sets, producing cells that are genetically identical to the parent cell

11
Q

Crossing over

A

occurs between prophase 1 and metaphase 1 and is the process where homologous chromosomes pair up with each other and exchange different segments of their genetic material to form recombinant chromosomes

12
Q

Recombinant chromosomes

A

combine DNA inherited from each parent

13
Q

True breeding

A

plants that produce offspring of the same variety when they self pollinate

14
Q

Hybridization

A

mating of 2 contrasting, true-breeding varieties

15
Q

The law of segregation

A

states that allele pairs separate or segregate during gamete formation, and randomly unite at fertilization

16
Q

Allele

A

Alternative version of a gene

17
Q

Independent assortment

A

each pair of alleles segregates independently of any pair of alleles during gamete formation

18
Q

Incomplete dominance

A

the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties. Not blending because recessive genotype/phenotype can be separated

19
Q

Codominance

A

two dominant alleles affect the phenotype in separate, distinguishable ways

20
Q

Pleitophy

A

multiple phenotypic effects

-cystic fibrosis and sickle cell anemia

21
Q

Epistasis

A

expression of a gene at one locus alters the phenotypic expression of a gene at a second locus

22
Q

Quantitative characters

A

are those that vary in the population along a continuum. Uses polygenic inheritance

23
Q

Polygenic inheritance

A

an additive effect of two or more genes on a single phenotype

24
Q

Carrier

A

heterozygous individuals who carry the recessive allele but are phenotypically normal

25
Q

Aminocentesis

A

the liquid that bathes the fetus is removed and tested

26
Q

Chorionic villus sampling

A

a sample of the placenta is removed and tested

27
Q

Chromosome theory of inheritance

A

Identifies chromosomes as the carrier of genes

- Sutton and Boveri

28
Q

Nondisjunction

A

Pairs of homologous chromosomes do not separate normally during meiosis
-as a result, only one gamete receives two of the same types of chromosome, and another gamete receives no copy

29
Q

Aneuploidy

A

results from the fertilization of gametes in which nondisjunction occurred

- offspring with this condition have an abnormal number of a particular chromosome
- aneuploid condition
30
Q

Mono sonic zygote

A

Has only one copy of a particular chromosome

31
Q

Trisomic zygote

A

has 3 copies of a particular chromosome

-ex trisomy 21, Down syndrome

32
Q

Polyploidy

A

a condition in which an organism has more than two complete sets of chromosomes

- triploidy: 3 sets
- tetraploidy: 4 sets
33
Q

Deletion

A

Removes a chromosomal fragment

34
Q

Duplication

A

Repeats a segment

35
Q

Inversion

A

Reverses orientation of a segment within a chromosome

36
Q

Translocation

A

Moves a segment from one chromosome to another

37
Q

Genomic imprinting

A

Phenotype variation, the phenotype depends on which parent passed along the alleles for those traits