#13 Genetics

Question 1

Genetics

Answer 1

Tell us how traits are passed down from one gen. to next

Question 2

Genes

Answer 2

• located on chromosomes (strands of DNA mol)

- diploid: one haploid from each parent

Question 3

Mendel (1860s)

Answer 3

• found specific ratio 3:1

- dominance: only one trait exhibited

Question 4

Alleles

Answer 4

Alt. forms of genes that cause diff heritable traits

Question 5

Homozygous

Answer 5

Two copies of same allele

Question 6

Heterozygous

Answer 6

One copy of each diff allele

Question 7

Dominant allele

Answer 7

Copy that is expressed

Question 8

Recessive allele

Answer 8

Copy that is not expressed

Question 9

Law of segregation

Answer 9

Allele pairs segregate during formation of gametes (one allele per gamete)

Question 10

Phenotype

Answer 10

Trait that is expressed

Question 11

Genotype

Answer 11

Genetic makeup

Question 12

Autosomal disorders

Answer 12

Recessive Disorders:
Albinism
-lack of pigment in skin
Cystic fibrosis
-excess muscle in lungs, digestive track, liver
Sickle-cell disease
-sickled red blood cells

Dominant disorders
Achondroplasia
-dwarfism
Hypercholesterolemia
-excess cholesterol in blood
-heart disease

Question 13

Law of Independent Assortment

Answer 13

Each pair of alleles segregates independently of the other pairs of alleles during gamete formation (only occurs when on different chromosomes, when on same chromosome: crossing over)

Question 14

Complication: incomplete dominance

Answer 14

Results in intermediate phenotypes (a blending)

Question 15

Complete dominance

Answer 15

Same phenotype whether one or two copies present (dom allele -> dom expressed)

Question 16

Complication: co-dominance

Answer 16

Heterozygote expresses traits of multiple alleles (e.g. blood type)

Question 17

Complication: pleiotropy

Answer 17

One gene affects many heritable traits (e.g. sickle cell anemia)

Question 18

Complication: polygenic inheritance

Answer 18

One heritable trait due to many genes, creates continuum of variation (e.g. skin color)

Question 19

Complication: environment

Answer 19

E.g. height can be influenced by nutrition, disease, sleep, exercise, etc.

Question 20

Complication: linked genes

Answer 20

Genes on same chromosome tend to be inherited together

Question 21

Complication: crossing over

Answer 21

Linkages among genera that are on the same chromosome may be broken by crossing over

Question 22

Sex determination

Answer 22

Female XX
Male XY

Leads to unique patterns of inheritance because sex linked genes (on sex chromosome)

Sex linked disorders affect mostly males (e.g. color blindness)

Question 23

Epigenetics

Answer 23

Change expression of gene

Temporary

Question 24

Microbiome

Answer 24

Bacteria passed on to children via birth canal and breast milk