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Flashcards in Genetics Deck (45)
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1

Heredity

The passing of traits from parent to offspring

2

Describe the law of dominance....

Some traits can mask other traits when both traits appear in the parents.

Ex: Red is dominant to white

3

Describe the law of segregation.....

During the formation of reproductive cells (sperm, egg) the paired factors (genes) separate from one another and then recombine.

4

Describe the law of independent assortment...

Each trait is inherited independent of one another

(Exception: blond hair, blue eyes)

5

Factor-
Gene-
Allele-

Describing a gene (mendels word)

Trait

A form of a trait

6

Describe incomplete dominance....

The two alleles are neither dominant or recessive. Both contribute to the phenotype of the offspring. (Blending)

Ex: Snap dragons

7

Describe co-dominance and multiple alleles....

Two alleles may contribute equally in the offspring and are both dominant. (No blending)

Example: speckled chicken produced from a black chicken and white chicken.

Or blood types (Type AB has both A and B)

8

Describe sex linked traits....

All organisms that reproduce sexually have a combination of X and Y chromosomes.

Male: XY Female: XX

9

Acquired trait

Inherited trait

Trait that has been learned
Ex: scars, attitude

Trait passed from parent to offspring (or from ancestor)
Ex: eye colour

10

Autosome

Non sex chromosome

11

Carrier

A female that carries a gene but does not express it in her phenotype.

Ex: Hemophilia (XRXr)

12

Chromosome

Threadlike structure carrying genetic information in the form of genes

13

Diploid

A cell that contains two sets of homologous chromosomes

14

Fertilization

During sexual reproduction, an egg and sperm combine to form a zygote

15

Gamete

Sex cell (sperm or egg)

16

Genotype

Symbolic representation of a characteristic

17

Haploid

A cell that contains only a single set of genes

18

Heterozygous

Having two different alleles for a particular gene

19

Homologous

Chromosomes in which one set comes from the male parent and one set from the female parent

20

Homozygous

Having two identical alleles for a particular gene

21

Karyotype

Micro graph showing the number and visual appearance of the chromosomes

22

Meiosis

Cell division that results in 4 daughter cells each with half the chromosomes as the parent.

Formation of gamers

23

Multiple alleles

3 or more alternative forms of a gene

24

Non disjunction

Failure of homologous chromosomes or sister chromatids to separate during cell division.

25

Phenotype

Physical characteristic of an organism

26

Pedigree

Diagram that shows the occurrence and appearance or phenotype of a genetic trait from one generation to the next within a biological family

27

Test cross

Genetic cross between homozygous recessive and a suspected heterozygous to determine the genotype of the later.

28

Tetrads

4 chromatids in groups of 2 formed in prophase 1

29

Synapsis

Fusion of chromosome pairs at the start of meiosis that enables crossing over to occur

30

Cystic fibrosis cause and symptoms

Autosomal recessive Inherited disease passes a defective gene that causes buildup of thick mucus that can damage organs. Clogs lungs and is associated with digestive problems.

31

Down syndrome causes and symptoms

Nondisjunction causes an extra chromosome 21 which leads to cognitive impairment, flattened facial appearance and upward slanted eyes.

32

Hemophilia causes and symptoms

Sex linked trait that can lead to lack of blood clotting proteins. This creates excessive bleeding.

33

Kleinfelter’s syndrome causes and symptoms

Due to non disjunction a big is born with an extra X chromosome resulting in small testicles, breasts and reduced muscle mass.

34

Marfan syndrome causes and symptoms

Autosomal dominant: Mutation of gene that makes fibrin (protein in connective tissue) inherited from one parent. Leads to disproportionate legs and arms, heart murmurs, tall and slender build

35

Turners syndrome

A female with only 1 X chromosome due to non disjunction. Girls affected are short, infertile and have heart defects.

36

Huntington’s

Autosomal dominant disorder causing progressive breakdown of nerve cells in the brain. Leads to uncontrollable movements, difficulty with speech, lack of awareness

37

Sickle cell disease

Autosomal recessive disease where abnormal (sickle shaped) hemoglobin are inherited. Causes fatigue, pooling if blood in spleen, low resistance to infection, and pain.

38

Autosomal recessive

Autosomal dominant

Two copies of abnormal gene must be present in order to develop le disease.

One copy of abnormal gene from one parent needed to get disease.

39

Two names of cells that become sperm and egg

Oogonial (overly)

Spermatogonial (testes)

Both diploid or 2n

40

Describe meiosis 1

Interphase- DNA duplicates 46 chromosomes (92) chromatids
Prophase- DNA condenses and homologous pairs match up for crossing over to transfer genetic information.
Metaphase- Chromosomes in pairs at equator of cell
Anaphase- Chromosomes pulled away
Telophase and cytokinesis- 2 new nuclei form 2 new cells

41

Describe meiosis 2

Prophase 2-Spindle form
Metaphase 2- Chromosomes lime up in single file line
Anaphase 2- Chromatids pulled away
Telophase 2 and cytokinesis- 4 haploid cells formed

42

What is the meaning of each....

P
F1
F2

P=parental generation
F1- First filial generation
F2- Second filial generation

43

Purebred

Hybrid

Organism that is the offspring of genetically similar parents that were both homozygous for a trait.

Organism that is the offspring of genetically dissimilar parents.

44

Dominant

Recessive

Expressed in phenotype


Only expressed in phenotype when paired with another recessive allele

45

Why do two heterozygous Tall plants create three tall and one short?

The paired genes separate and recombine. (Law of segregation)

TtxTt=TT, Tt,Tt,tt
3:1