Genetics Final Exam 2023 Questions with correct Answers (Graded A)

What are deleterious genes and list one example - Answer- alleles whose phenotype results in significantly reduced fitness of an animal; Dexter cattle - short legs Genetics - Answer- The scientific study of heredity and hereditary variation. Gregor Mendel is often referred to as - Answer- "Father of Genetics" What plant did Gregor Mendel study? - Answer- peas Why was Mendel more successful than other researchers? (what were they looking for or at differently) - Answer- 1. Picked easy organism to experiment 2. Picked plant that was diploid 3. Picked traits that were simply inherited 4. Mendel looked at traits separately Define genetic improvement and list 3 examples - Answer- The betterment of an organism; 1. bigger 2. smaller 3. faster 4. hairless 5. quicker weight gain Who created the term "genetics?' - Answer- William Batesone What is a chromosome? - Answer- a DNA molecule composed of RNA and proteins to form a threadlike structure; only visible during meiosis and mitosis (contains the genes) What is located on a chromosome? - Answer- genes What is the appearance of the structure of a DNA strand? - Answer- double helix Define DNA - Answer- Genetic material makes up a gene and then makes up a chromosome List the bases that make up DNA - Answer- Adenine Guanine Cytosine Thymine What DNA bases are paired together? - Answer- Adenine - Thymine Cytosine - Guanine List one dominant trait and the corresponding recessive trait Cattle - Answer- Dominant - polled Recessive - horned List one dominant trait and the corresponding recessive trait Chickens - Answer- Dominant - feathered shanks Recessive - clean shanks List one dominant trait and the corresponding recessive trait Horses - Answer- Dominant - smooth hair Recessive - curly hair List one dominant trait and the corresponding recessive trait Dogs - Answer- Dominant - wire hair Recessive - smooth hair List one dominant trait and the corresponding recessive trait Cats - Answer- Dominant - short hair Recessive - long hair List one dominant trait and the corresponding recessive trait Tomato - Answer- Dominant - small fruit Recessive - large fruit List pairs of characteristics and the traits (specific phenotypes) of each trait Mendel studied: Seed color - Answer- yellow, green List pairs of characteristics and the traits (specific phenotypes) of each trait Mendel studied: Flower color - Answer- purple, white List pairs of characteristics and the traits (specific phenotypes) of each trait Mendel studied: Seed shape - Answer- round, wrinkled List pairs of characteristics and the traits (specific phenotypes) of each trait Mendel studied: Pod color - Answer- green, yellow List pairs of characteristics and the traits (specific phenotypes) of each trait Mendel studied: Pod shape - Answer- inflated, constricted List pairs of characteristics and the traits (specific phenotypes) of each trait Mendel studied: Flower position - Answer- axial, terminal List pairs of characteristics and the traits (specific phenotypes) of each trait Mendel studied: Plant height - Answer- tall, dwarf What is a testcross? - Answer- A cross between an individual whose genotype at one or more loci may be unknown and an individual who is homozygous recessive of the genes in question What is the genotype of the parental cross (in a monohybrid) for a testcross? - Answer- G? x gg List the resulting phenotypic and genotypic ratios of a testcross - Answer- Alternative 1 - PR all have same phenotype of dominant trait; GR all have the same heterozygous genotype Gg Alternative 2 - PR 1:1 half have dominant trait and half recessive trait, GR 1:1 half heterozygous, half homozygous recessive What does a test cross hope to confirm about one of the parents? - Answer- determine is the unknown parent is homozygous dominant or heterozygous What ratio does epistasis effect? - Answer- phenotypic ratio What generation does epistasis effect? - Answer- F2 List 3 commonly affected ratios as a result of epistasis - Answer- 13:3 9:6:1 12:3:1 If a plant is tall (TT) and is crossed with a plant that is short (tt), list the phenotype of the F1 if the following dominance categories occur: - Answer- Complete dominance: tall Incomplete dominance: medium height Codominance: some tall What is polydactyly? - Answer- having more than the normal number of fingers and/or toes How many traits can be affected by one gene? - Answer- one gene can affect one or more traits Traits are affected by genes and what other factor? - Answer- environment Explain what a mutant is at the DNA level. - Answer- change in base sequence in DNA What is wild-type? - Answer- non-mutant (normal) In sickle-cell anemia (disease where pleiotrophy occurs), what is the mutant substitution? - Answer- T-A instead of A-T What trait does epistasis primarily effect? - Answer- color Explain epistasis of tomatoes (Yellow fruits and red fruits). - Answer- dominant genes are both required to produce red color; at least one dominant of each gene - can not be from just one gene On a punnet square, which sex is the vertical line? - Answer- female On a punnet square, which sex is the horizontal line? - Answer- male Diploid - Answer- 2 sets of chromosomes Gene - Answer- unit of heredity that occupies a specific location on a chromosome Allele - Answer- 1/2 of a gene pair Hybrid - Answer- offspring of 2 varieties that differ in one trait or more Dominant - Answer- trait that is expressed Recessive - Answer- trait not expressed, unless no dominant is present P1 - Answer- true-breeding generation F1 - Answer- 1st offspring generation Selfing - Answer- crossing one generation to itself Genotype - Answer- genetic make-up Phenotype - Answer- external physical appearance or observable characteristic Homozygous - Answer- gene made of alleles that are the same Heterozygous - Answer- gene made up of different alleles Homozygous dominant - Answer- RR Homozygous recessive - Answer- rr List 1 other commonly affected trait that is affeccted by 2 genes (epistasis effects) and creat novel phenotypes. Explain the gene action on the phenotypes. - Answer- Squash shape; 2 dominants will produce a specific shape, 2 recessive will produce a different specific shape; a dominant and recessive will pro