test 6 Flashcards
- Which statement does not describe a classical assumption most scientists and the general public had before the experiments of Kolreuter (1760s), T.A. Knight (1832) and Mendel?
- you can take two different species with same body parts and get an offspring (minitar, goat headed man)
- species don’t change over time (obviously not true, constant changes, species never stay the same)
- if you have something physically happen to you, you’re child would receive the same thing (traits will be transmitted genetically)
- What were the findings of Josef Kolreuter (1760s) regarding patterns of inheritance?
tried to complete hybridization in plants in the 1760s. Different strains of tobacco plants were cross-fertilized and obtained fertile offspring. Wanted to see what would be produced and got different results, so he stopped his discoveries here.
- What were the findings of T.A. Knight (1832) regarding patterns of inheritance?
True-breeding; noticed that when bred 2 white you only got white over time; bred 2 purple you would get white sometimes. He never got the answer. Worked with pea plants.
- What is the definition of true-breeding?
true-breeding: the offspring produced from self-fertilization (breeding by yourself) remained uniform from one generation to the next
- Mendel, through his pea experiments, came up with the terms segregation, character, and traits. How are these words related to one another?
segregation: when some offspring exhibited alternative forms of a character = different physical traits/features (remember why . . . because of crossing over, synapsis, separation during anaphase, you will have completely different gametes)
characters: physical representation of your genetics
Traits: different forms of your characteristics (based on your genetics)
- Male and female sexual organs are enclosed within a pea flower which Mendel used. He would self-pollinate and cross-pollinate to obtain his results. What is the difference between self-pollination and cross-pollination?
self (male and female sex organs creating a zygote from the same plant)
cross-fertilization (different individual plants, but same species creating a zygote)
- What is the difference between a dominant and recessive trait?
Dominant- traits always show up
Recessive- traits only show up sometimes if the dominant trait isn’t present
- What is the (a) genotypic and (b) phenotypic ratio of the offspring of a monohybrid cross of a heterozygous male and heterozygous female plant? H = tall and h = short
genotypic ratio: HH, Hh, HH, and hh (50% HH, 25% Hh, and 25% hh) 1:2:1
Phenotypic ratio: 75% tall and 25% short (3:1)
- What is the (a) genotypic and (b) phenotypic ratio of the offspring of a monohybrid cross of a homozygous short male and a heterozygous female plant? H = tall and h = short
genotypic ratio: Hh and hh (50% Hh and 50% hh)
Phenotypic ratio: 50% tall and 50% short
- What does it mean that Mendel discovered a “disguised ratio?”
the recessive trait was hidden
- What is the definition of a gene?
Particular DNA nucleotide sequence
- What is the definition of an allele?
alternative varying genetic traits, represent phenotypes
- What is the definition of a locus?
particular location of a gene on a chromosome
- What is the difference between a homozygous and heterozygous individual?
-HH and hh are homozygous, no alternative allele
-Hh is always heterozygous, alternating alleles
- What is the difference between a genotype and phenotype?
-Genotypes: alleles, gene (hh)
-Phenotypes: physical representation
- What does it mean that Mendelian genetics are considered “discrete” genetics?
The dominant will always show up if present (one or the other)
○ The recessive allele will not show unless there are two there
○ Both alleles will not be shown proportionally in a heterozygous individual
- Which statement does not describe Mendel’s First Law of Heredity: Segregation?
You won’t look exactly like you’re parents because during synapsis and crossing over your genetics get mixed up and then gets decided which sides they go to and then form 4 different gametes
- What is the difference between completing a monohybrid verses dihybrid test cross?
Monohybrid test cross - only one character (one thing)
Dihybrid test cross - two characters (two things)
- Which statement describes the results of Mendel’s experiments for dihybrid crosses?
If you breed two complete heterozygous it will always be a 9:3:3:1 phenotypic ratio
- What do the letters on the outside of the Punnett square stand for?
Gametes of parents
- What do the letters on the inside of the Punnett square stand for?
Possible genotypes of their offspring
- What is the (a) genotypic and (b) phenotypic ratio of the offspring of a dihybrid cross of a homozygous tall and green male and homozygous short and yellow female plant? H = tall, h = short, G = green, and g = yellow
genotypic ratio: HhGg (100% HhGg)
phenotypic ratio: 100% tall and green
- What is the phenotypic ratio of the offspring of a dihybrid cross of a heterozygous male and a heterozygous female plant? H = tall, h = short, G = green, and g = yellow
Phenotypic ratio: 9:3:1
- Hornless (H) in cattle is dominant over horned (h). A homozygous hornless bull mated with a homozygous horned cow. What will be the genotype and phenotype of the first generation?
Genotype - Hh
Phenotype - hornless cattle
- In tomatoes, red fruit (R) is dominant over yellow fruit (r). A plant that is homozygous for red fruit is crossed with a plant that has yellow fruit. What would be the genotypes and phenotypes of the P1 and F1 generations?
Genotypes: RR : Rr : rr = 1 : 2 : 1
Phenotype: 75% plants red fruit, 25% plants yellow fruit
- In humans, being a tongue roller (R) is dominant over non-roller (r). A man who is a non-roller marries a woman who is heterozygous for tongue rolling. What is the probability of this couple having a child who is a tongue roller?
50%
- Brown eyes in humans are dominant over blue eyes. A brown-eyed man, whose mother was blue-eyed, marries a brown-eyed woman whose father had blue eyes. What is the probability that this couple will have a blue-eyed child?
25%
- What is the Law of Independent Assortment regarding genetics?
genes located on different chromosomes, assort independently
- Regarding non-Mendelian genetics, which statement accurately describes continuous variation?
the greater the # of genes that influence a character, the more continuous, the expected distribution of the character.
- Regarding non-Mendelian genetics, which statement describes an example of continuous variation discussed in class?
Ie. height and weight. Extremes are very rare; if both parents have a fast metabolism, you most likely will have a fast metabolism. Intermediates are more common.
- Regarding non-Mendelian genetics, which statement accurately describes pleiotropic effects?
an individual allele has more than 1 effect on the phenotype.
- Regarding non-Mendelian genetics, which statement describes an example of pleiotropic effects discussed in class?
Ie. Let’s say you have sickle cell disease you can inherit, but because of that one disease, you can have multiple issues because of ONE disease. One disease= multiple problems
- Regarding non-Mendelian genetics, which statement accurately describes incomplete dominance?
non-mendelian genetics; not all alternative alleles are fully dominant or fully recessive in heterozygotes.
- The coat color in mice is incompletely dominant. Yellow and white-colored mice are homozygous, while cream-colored mice are heterozygous. If two cream-colored mice mate, what phenotypic ratio can we expect of their offspring?
1:2:1 phenotypic ratio
- In radishes, red and white are pure-breeding colors, while hybrids are purple. If a red radish is crossed with a white radish, what will be the phenotype of the F2 generation (assuming the F1generation self-pollinates)?
Phenotype: 1 red, 2 purple,1 white
- Regarding non-Mendelian genetics, which statement describes an example of incomplete dominance discussed in class?
A cross between white- and red-flowering carnation plants may result in offspring with a phenotype of pink flowers.
- Regarding non-Mendelian genetics, which statement accurately describes environmental effects affecting genetic expression?
the degree to which an allele is expressed may depend on the environment.
- Regarding non-Mendelian genetics, which statement describes an example of environmental effects affecting genetic expression discussed in class?
Ie. an arctic fox will be white in the winter and brown in the summer because certain conditions and temperatures can make it change, are your genetics chosen? NO
- Regarding non-Mendelian genetics, which statement accurately describes epistasis?
one gene interferes w the expression of another gene. Only going to work with dihybrids, nothing is ever going to be fully dominant or fully recessive,
- Regarding non-Mendelian genetics, which statement describes an example of epistasis discussed in class?
this means you have to have a dominant gene from each parent to get a purple corn. If you have A and B you will have purple corn. Have to have at least one capital dominant of each.
- Carl Correns (1900) and Walter Sutton (1902) were two scientists who contributed to the discovery of the chromosomal theory of inheritance. Which statement describes this theory?
true
- Carl Correns’s (1900) and Walter Sutton’s (1902) work led to the chromosomal theory of inheritance. Which of these statements describe this theory?
First principle: diploid individuals=2 copies of each pair of homologous chromosomes and gametes=1
Second principle: Chromosomes segregate during meiosis (like the mendel model)
- Which statement does not describe the results of Thomas Hunt Morgan’s sex-linked experiments (know information pertaining to the 𝐹1 and 𝐹2 generations)?
wanted to redo Mendel’s work and accidentally worked with sex-linked traits. Wanted to look at the eye color of fruit flies mother red eye dominant and father white eyes (F1 results), F2 results took females that are carriers and the male was normal and he got 2 females that got red eyes and male 50% that could get red eyes and male 50% that could get white eyes.
- A trait determined by a gene on the X chromosome is said to be ————– because the behavior of the trait in crosses correlates with the sex of the individual. Fill in the blank.
sex-linked (x-linked) trait
- Color blindness is a recessive, sex-linked (X-linked) disorder in humans. A colorblind man has a child with a woman who is a carrier of the disorder. What is the chance that the offspring will be colorblind?
50%
- In Guinea pigs, the genotype (BB) is black, and the genotype (bb) is white color, and (Bb) is gray color, The gene (B) and (b) are sex-linked. What type of offspring are to be expected in a cross between a gray female and a black male?
The offspring is 100% going to be black
- In fruit flies, white eyes is a sex-linked recessive trait. Normal eye color is red. If a white-eyed male is crossed with a heterozygous female, what is the proportion of the offspring will have red eyes?
2:4 or 1:2 ratio
- Is sex determination the same in all organism? (know the answer and anything else we discussed regarding this question)
Sex determination is not the case in all organisms because sometimes the male has a double of the same letter and the female has the equivalent of what we call X and Y. All organisms do not have the same sex determination as humans do.
- Usually only ——- (number) is activated in each female mammal. Fill in the blank.
2?
- The inactivated X chromosome of a female is highly condensed making it visible as an intensely staining —— attached to the nuclear membrane. Fill in the blank.
Barr body
- Females that are heterozygous for X chromosome alleles are ———–. Their individual cells may express different alleles, depending on which chromosome is inactivated. Fill in the blank.
genetic mosaics
- As distance between two genes on a chromosome ———, the probability of recombination between them increases. Fill in the blank.
increases
- Regarding changes in chromosomes, what is disjunction?
The normal separation or moving apart of chromosomes toward opposite poles of the cell during cell division.
- What is the definition of (a) aneuploidy, (b) monosomy, or (c) trisomy?
Aneuploidy: gain or loss of a chromosome; frequency: happens in 7-10% of the gametes created
- Which statement describes an example discussed in class regarding Y chromosomal genetic defects?
Jacob’s syndrome
- Which statement accurately describes how someone would receive either (a) sickle-cell disease, (b) hemophilia, or (c) Huntington’s disease?
-Hemophilia: sex linked recessive disorder, males much more likely to get this disorder, male that has this and a female that is a carrier get hemophilia, it’s when your blood can’t clot well and you bleed out to death
-Sickle-cell anemia: recessive disorder, changes concavity of your red blood cells
-Huntington’s disease: dominant, if you have this you don’t want to pass this to your kids, effects your brain and muscles, die at a very young age, doesn’t have a cure, need one big H to be present
- Know how to read a pedigree chart and be able to interpret the answers for (a) reading generations, (b) reading male from female, (c) knowing if someone has a disease, and (d) being able to figure out if the disease is recessive or dominant.
- According to the video Incomplete Dominance, Codominance, Polygenic Traits, and Epistasis, what is the definition of codominance?
Codominance- alleles work together
- According to the video Incomplete Dominance, Codominance, Polygenic Traits, and Epistasis, what would be the color of chicken offspring of BB (black) and WW (white) parents following codominance genetic rules? Why does this occur?
The offspring would be black and white, speckled. This occurs because both traits show up in the essence of codominance.
- According to the video Incomplete Dominance, Codominance, Polygenic Traits, and Epistasis, what are polygenic traits?
Polygenic traits: Many genes coding for one traits
- According to the video Incomplete Dominance, Codominance, Polygenic Traits, and Epistasis, both height and skin color can be influenced by ——– factors. ————— can affect your height and spending a lot of time in the sun can affect your ———. However, it cannot affect your genetics for a trait. Fill in the blanks.
environmental
nutrition
skin color
- Mitochondrial and chloroplast genes are inherited from the female parent (from the egg cell during fertilization). Why?
Mitochondria has its own genetic information, female passes these genes because inside her egg cells she can fit these genes because she has a lot more space.
- A mode of uniparental inheritance from the mother is called —————. Fill in the blank.
maternal inheritance
- How are mitochondrial genes inherited?
mitochondrial genes are inherited only from the mother.
- Most mitochondrial genes encode proteins that are part of your ATP synthase and the protein complexes of the electron transport chain. If these are mutated or damaged, it can affect your nervous system and metabolic functions. For example, ———————— can be caused and result in optic neuron degeneration over time. Fill in the blank.
leber’s hereditary optic neuropathy
- How are chloroplast genes inherited?
Chloroplasts were individual bacterium that formed in plant cells and inherited and never left since. Inherited only by female plants.
- According to the video Multiple Alleles (ABO Blood Types) and Punnett Squares, what happens if you try to give a B-antigen person (a) A-antigen, (b) AB-antigen, or (c) O-antigen blood?
A, AB) immune system doesn’t recognize and will attack O) safe because it doesn’t have A or B antigens
- According to the video Multiple Alleles (ABO Blood Types) and Punnett Squares, why can O-antigen blood only receive donated blood from an O-antigen individual?
O blood does not have A or B antigens so it will attack and can only receive O blood.
- According to the video Multiple Alleles (ABO Blood Types) and Punnett Squares, which blood type is a universal acceptor? Why?
AB because they have both A and B antigens and O has no antigens to worry about
- According to the video Multiple Alleles (ABO Blood Types) and Punnett Squares, what does it mean your blood is + or – ?
If you are positive you have a protein called Rh factor, if you are negative you don’t have the Rh factor protein
