Genetics Flashcards Up to Lec 3

What is genetics?

The scientific study of heredity

Who is considered as the father of genetics

Gregor Mendel

What is monohybrid inheritance?

Inheritance of a characteristic controlled by a single gene

What is a dihybrid cross?

inheritance controlled by two genes

What is a gene?

A segment of DNA that codes for a protein; sequence r nucleotides in DNA used to produce a polypeptide chain

Where are genes located?

Chromosomes

What are allelles?

Variations of a gene

What is a locus?

Location of a gene on a chromosome

What is a character?

A phenotypical trait or a physical trait observed

What is an example of an character?

Eye color

What is a trait?

A specific characteristic of the character variations

What is an example of a trait?

Blue eyes, brown eyes, grey eyes, or green eyes

What is the first filal generation?

The first crossing over pair

What is a second filal generation?

The second crossing over pair

What is a hybrid?

A mix of two different traits

What is the phenotypic ratio when you mix two hybrids (heterozygous) in a monohybrid cross?

3:1

What is the genotypic ratio when you mix two hybrids (heterozygous) in a monohybrid cross?

1:2:1 (homozygous recessive: hererozygous: homozygous dominant)

What is dominant gene?

A gene that produces a functional protein

What is a recessive gene?

A gene that produces a non-functional protein

What are some examples of recessive genes?

A folly tongue, no hair in fingers, first toe larger, and freckles

What are some examples of dominant genes?

Normal tongue, hair on fingers, second toe larger, and no freckles

What does homozygous mean?

Same allelles on the chromosome

What does heterozygous mean?

hybrid; two different alleles; typically a carrier

What is true breeding?

When the organising mates they produce only one consistent result

What is a phenotype?

Physical appearance or expression of the genotype; do not need to go within the genes to identify the specific gene

What is a genotype?

genetic makeup of an organism

What is Rh positive?

Presence of rh proteins

What is Rh negative?

Absence of rh proteins

What are the 3 Mendel laws?

1. Law of Segregation

2. Law of Independent Assortment

3. Law of Dominance

What is the law of segregation?

The two alleles for each character segregate (separate) during gamete production.

What is the law of independent assortment?

genes for different traits can segregate independently during the formation of gametes

What is the law of dominance?

If two alleles differ, then one, the dominant allele, is fully expressed in the the organism's appearance

What is a test cross?

crossing an organism with a dominant phenotype with one that has a recessive phenotype

What is albinism?

Recessive condition; a mutated gene that produces a malfunctioning protienninvolved in melinin production

What is cystic fibrosis?

High levels of chloride due to enzyme malfunction

What is Tay-Sachs?

When a dysfunctional enzyme cannot break down brian lipids

What is sickle cell anemia?

Amino acid# changes creating a sickle shape

What is androplasia?

Dwarfism dominant gene

What is Huntington's disease?

degenerative disease of the nervous system

What is polydactyly?

extra fingers or toes

How do you complete a dihybrid cross?

You foil out the genomes of the parents and organize them on the punnet square

What is the phenotypic ratio of a dihybrid cross with heterozygous parents?

9:3:3:1

What is a double heterozygote?

When an individual is heterozygous for both genex

what is a genotypic ratio?

List of all the possible genes ratios and combinations

What are the 4 types of non-mendelian inheritance?

Incomplete dominance, codiminance, multiple allelles, and pleiotrophy

What is incomplete dominance?

A belnding of traits

What are some characteritics of incomplete dominance?

more than one phenotype

genotype and phenotype ratios match

heterozygote has its own phenotype

What is codiminance?

where the phenotype produce by both alleles are expressed simultaneously

What are the genotypes for type a blood?

A or Ai

What are the genotypes of type B blood?

B or Bi

What are the genotypes of type AB blood?

AB

What is the genotype for type O blood?

ii

What blood type is the universal recipient?

AB (it has both antigens so the body produces no antibodies against type A or B)

What is the universal donor?

Type O (has no antigens so will activate no antibodies)

What is coagulation?

blood clotting; blood clots with antibodies for certain types and if it doesn't clot then that's your blood type

What is RH?

An inherited protein found on the surface of red blood cells

What are the genotypes for a positive blood type?

Rr or RR

What are genotypes for a negative blood type?

rr

What is pheilortropic traits?

Traits that can produce more than one phenotypic character

What is an example of a pheilotropic trait?

Sickle cell (you can have normal, mix, and sickled)

What are polygenic genes?

traits controlled by two or more genes

What are examples of polygenic genes?

Epistatisis, quantitative traits, linkage

What is epistasis?

One gene can override another; one gene in a chromosome affects the expression of genes in other chromosomes

What is an example of epistatis in mice?

Mice have two genes for fur color; the actual color and a color deposit gene. If the mice is cc for the color deposit gene no melanin will be deposited and the mouse will be white no matter what B (black) or b (brown) traits are present

What is the epistasis ratio?

9:3:4

What are quantitative traits?

Traits that vary constantly within a population; influenced by many genes and environment

What is phenotypic plasticity?

Some genotypes can have two phenotypes depending on environmental conditions

What is an example of phenotypic plasticity?

A bunny turns black when exposed to the cold. When an ice pack is attached to its back the spot where the ice pack is gradually turns black

What is linkage?

Certain genes are inherited together and are found on the same chromosome

What factor determines linkage?

Distance of genes on the chromosomes

What is only process that can break linkage?

Crossing over

If a queysion includes linkage…

then you do not foil the characterotics

What is incomplete linkage?

Genes that are partially linked making recombination of traits rare but not impossible

What is sex determination?

the mechanism by which the sexual phenotype of an individual is established in a given species

What are 4 common types of sex determination

XY, X0, XW, haploid-diploid

What is the XY system?

XY genes determine male gender, XX determines females

Where is the XY system found?

Humans and drosphila flies

What is the X0 sex determination?

XX for females and X for males

What is the XW system for sex determination?

XX for makes and XW for females

What is the haploid-diploid system?

females diploid, males haploid

What is nondisjunction?

Misseperstion of chromosomes during meiosis causing certain genetic conditions

What is Turner Syndrome?

Occurs in females when they only have one X chromosome; causes sterilization

What happens when a females has 3X's

The female is normal

What is Klinefelter syndrome?

XXY, male has smaller testes, sterile, and has enlarged beasts

wHat happens when a male is XYY?

they are normal (over 50% of the population is afflicted)

What are normal characteristics referred to as?

Wild type

What are mutated characteritics referred to as?

Mutant types

What are sex-linked traits?

Certain genes are carried on the x chromosome

What are some sex linked conditions?

Red-green color blindeness and hemophila

What is a Barr body?

inactive X chromosome, only one x chromosome is active in every cell

What are viruses made of?

Dna, rna, and a protein coat

How do viruses reproduce?

By injecting DNA or RNA into cells and enslaving the cell to produuce mord virus copies

How did Griffith discover transformation?

Griffith wanted to find out how the bacterial caused pneumonia, so he isolated 2 different strains: a harmful s strain and a harmless R strain. He then injected rats with the dead s strain and all the rats survived. Then he injected the rats with a mix of the s and r strain and the rats developed pneumonia. He predicted that the bacteria shared information between each other

What is Chargraff's rule?

A=T and C=G; the percentage of A's will always be approximately equal to the percentages of T's andnite same for guanine