With your host…Ms. Turner! Genetics and Monohybrid & Dihybrid Cross Test Review

VocabMendel’s Laws Monohybrid Cross Dihybrid Cross Miscellaneous

Vocab: 10 Define genetics. ANSWER

Vocab: 10 - Answer Genetics is the study of biological inheritance patterns (how traits are passed from parent to offspring) and variation in organisms.

Vocab: 20 What does it mean for a genotype to be homozygous? (I’m looking for a specific vocab word in your answer) ANSWER

Vocab: 20 - Answer A homozygous genotype has two of the same alleles (versions of a gene). Ex: TT or tt

Vocab: 30 What are chromosomes made up of? What is a gene? ANSWER

Vocab: 30 - Answer Chromosomes are made of supercoiled DNA (with the help of proteins – histones). Genes are segments of DNA that code for a particular trait.

Vocab: 40 What is the difference between genotype and phenotype? ANSWER

Vocab: 40 - Answer Genotype is the genetic makeup of a specific set of genes (the genetic information) and phenotype is the physical characteristics or TRAITS THAT ARE EXPRESSED.

Vocab: 50 What is a Punnett square? (use the correct vocabulary) ANSWER

Vocab: 50 - Answer A Punnett square is a grid system for predicting the possible offspring genotypes resulting from a cross.

Mendel’s Laws : 10 What did Mendel call traits that could “hide” for a generation? What is the trait that overshadows the trait that hides? ANSWER

Mendel’s Laws : 10 - Answer A recessive trait can be hidden for one or more generations and then be expressed only when two alleles for the recessive trait are inherited. A dominant trait will be expressed if one copy of the gene (or allele) is present.

Mendel’s Laws : 20 What does the Law of Segregation state? ANSWER

Mendel’s Laws : 20 - Answer The Law of Segregation states the organisms inherit two copies of each gene (one from each parent) and that organisms donate only one copy of each gene in their gametes…THUS the two copies of each gene segregate, or separate, during gamete formation.

Mendel’s Laws : 30 How is Mendel’s Law of Segregation shown while using Punnett squares? ANSWER

Mendel’s Laws : 30 - Answer When the parent genotypes are split (segregated) and one letter is written next to each box, it is showing that the offspring will only inherit one copy of a gene (allele) from each parent.

Mendel’s Laws : 40 How do Punnett squares show Mendel’s Law of Independent Assortment? ANSWER

Mendel’s Laws : 40 - Answer Different traits appear to be inherited separately – by showing all of the possible combinations for offspring genotypes (filling in the squares) you show that it is random which genes are inherited.

Mendel’s Laws : 50 When in meiosis does the Law of Independent Assortment take place? When in meiosis does the Law of Segregation take place? ANSWER

Mendel’s Laws : 50 - Answer The Law of Independent Assortment takes place in Metaphase (could be I or II, we stressed it in I when the tetrads straddle the metaphase plate). The Law of Segregation takes place in Anaphase II when sister chromatids split leaving you with 1 copy of each chromosome. (I could see Anaphase I also being an acceptable response )

Monohybrid Cross : 10 Write three different genotypes: Homozygous Dominant Heterozygous Homozygous Recessive (you can use any letter) ANSWER

Monohybrid Cross : 10 - Answer Homozygous Dominant - TT Heterozygous - Tt Homozygous Recessive - tt

Monohybrid Cross : 20 In Nicotiana plants, the allele for green leaves (G) is dominant over the allele for yellow leaves (g). Make a Punnett square to show the cross for a GG plant and a Gg plant and write the genotypic and phenotypic ratios. ANSWER

Monohybrid Cross : 20 - Answer Gg GGGGg GGGGg Genotypic Ratio – 2:2:0 or 1:1:0 Phenotypic Ratio – 4:0 or 1:0

Monohybrid Cross : 30 If you perform a cross between two heterozygous individuals, what percentage of the offspring would express the recessive trait? (you can do a Punnett square to figure it out, but you need to write your answer in a percent) ANSWER

Monohybrid Cross : 30 - Answer 25% (1/4) of the offspring would express the recessive trait. Gg GGGGg g gg

Monohybrid Cross : 40 Determine the possible genotypes and phenotypes of the offspring for a family whose mother has a smooth chin and whose father has a cleft chin. If that’s all the information I give you…what should you do… Cleft Chin (L) Smooth Chin (l) ANSWER

Monohybrid Cross : 40 - Answer Possible genotypes: Ll or ll. ll LLl lll ll LLl L

Monohybrid Cross : 50 A husband and wife recently returned home from the hospital with their newborn and are starting to think that maybe the baby is not actually their own. Neither the husband nor the wife has a widow’s peak, but their baby does have a widow’s peak. Determine the genotypes of the mother and father and the possible genotypes and phenotypes for any child of theirs. Free Ear Lobes (E) Attached Ear Lobes (e) Could the baby be theirs? ANSWER

Monohybrid Cross : 50 - Answer No, the kid couldn’t theirs. They do not have the dominant allele or else they would express it. Milkman??? ee eee e

Dihybrid Cross : 10 What is a dihybrid cross? ANSWER

Dihybrid Cross : 10 - Answer It’s a cross that shows the inheritance of TWO traits.

Dihybrid Cross : 20 In rabbits, grey hair (G) is dominant to white hair (g). Also in rabbits, black eyes (B) are dominant to red eyes (b). What would the phenotype be for a rabbit with the genotype Ggbb? ANSWER

Dihybrid Cross : 20 - Answer Ggbb would have a phenotype of grey hair and red eyes.

Dihybrid Cross : 30 In rabbits, grey hair (G) is dominant to white hair (g). Also in rabbits, black eyes (B) are dominant to red eyes (b). What would be the possible gametes for a rabbit with the genotype Ggbb? ANSWER

Dihybrid Cross : 30 - Answer Gametes for Ggbb: Gb gb (use FOIL to make sure you get all the combinations)

Dihybrid Cross : 40 In rabbits, grey hair (G) is dominant to white hair (g). Also in rabbits, black eyes (B) are dominant to red eyes (b). Use a Punnett square to show a cross between a male rabbit with the genotype GGbb with a female rabbit with the genotype ggBb. ANSWER

Dihybrid Cross : 40 - Answer Gb gBGgBb gBGgBb gbGgbb gbGgbb

Dihybrid Cross : 50 Show the parent cross and Punnett Square that would give you a phenotypic ratio of 9:3:3:1. (Use any letter) ANSWER

Dihybrid Cross : 50 - Answer MTMtmTmt MTMMTTMMTtMmTTMmTt MtMMTtMMttMmTtMmtt mTMmTTMmTtmmTTmmTt mtMmTtMmttmmTtmmtt

Miscellaneous: 10 True or False: Environment has no effect on an organism’s traits. ANSWER

Miscellaneous: 10 - Answer False Environment DOES have an effect on an organism’s traits. Click Here

Miscellaneous: 20 Put these 6 items in order from LARGEST to SMALLEST: DNA, Chromosomes, Human Body, Genes, Cells, Nucleus ANSWER

Miscellaneous: 20 - Answer Human Body, Cells, Nucleus, Chromosomes, Genes, DNA

Miscellaneous: 30 Draw a pair of single-stranded homologous chromosomes that have two genes on it: hair texture (T) and hair color (H). The genotypes for hair texture is heterozygous and for hair color is homozygous dominant. ANSWER

Miscellaneous: 30 - Answer It doesn’t matter the location you choose for the genes, however, the pairs need to be in the same location on the two chromosomes (in other words, the alleles for hair color should be in the same spot on the two chromosomes).

Miscellaneous: 40 What are the four phenotypic categories for a dihybrid cross? (when we write a dihybrid phenotypic ratio it has four slots, what do those four slots represent if you have to describe it using words?) ANSWER

Miscellaneous: 40 - Answer Expresses the ____ trait for trait #1, and the ____ trait for trait #2 Dominant, Dominant Dominant, Recessive Recessive, Dominant Recessive, Recessive

Miscellaneous: 50 If the mother of a family is ‘normal’ but carries the recessive gene for cystic fibrosis and the father is also normal and does not carry the gene for cystic fibrosis, what are the chances of them having a child with a cystic fibrosis? Cystic Fibrosis (has C.F. Disease) (f) Normal (no C.F. Disease) (F) ANSWER

Miscellaneous: 50 - Answer Mother: Ff Father: FF They have a 0% chance of having a child with Cystic Fibrosis because you need to have the genotype ff to express that trait. Ff FFFFf FFFFf