Genetics (20%) Sample Test Prep Questions

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1 Genetics (20%) Sample Test Prep Questions Grade 7 (2a Genetics) Students know the differences between the life cycles and reproduction methods of sexual and asexual organisms. (pg. 106 Science Framework) Summary: Sexual reproduction entails fertilization, an event in animals that requires the fusion of an egg cell with a sperm cell. The fertilized egg (the zygote) goes through a series of cell divisions (mitosis) and developmental steps to generate a new organism genetically related to its parents. Pollination of flowering plants and growth of a new genetically related plant from seed are more examples of a sexual life cycle. Some organisms exclusively reproduce without a fertilization event. This method is called asexual reproduction. Protists (single-celled eukaryotic organisms) often have no known sexual cycle and reproduce solely by mitotic division. Fungi and plants often have both sexual and asexual method of reproduction. Massachusetts Released Question Single celled organisms can reproduce and create cells exactly like themselves without combining genes from two different parent cells. When they do this, they use a type of A asexual reproduction B gamete formation C natural selection D sexual reproduction Answer: A. asexual reproduction During mitosis, the doubling of chromosomes ensures that both new cells. A have identical genetic makeup B are twice the size of the parent cell C serve different functions D remain attached to each other Answer: A have identical genetic makeup

2 Oregon Released Question Many plants reproduce asexually. How does the genetic material (DNA) compare between the new plant and the parent plant in this type of reproduction? A It is similar but not identical B It depends on the plant the parent was crossed with C It depends on the climate it is grown in D It is identical Answer: D It is identical Grade 7 (2c Genetics) Students know an inherited trait can be determined by one or more genes. (pg. 107 Science Framework) Summary: This standard draws a correlation between genes and the inherited trait or features of an organism. A single gene can determine an inherited trait. For example, attached or unattached earlobes is an inherited trait typically determined by a single gene (inherited from each parent). A single gene may affect more than one trait or feature in an organism. Many traits, such as hair and eye color, are determined by multiple genes and do not have simple patterns of inheritance. Although an organism s genes define every inherited trait, there is not always a one-to-one correspondence between trait and gene. Illinois State Released Question This is a diagram of a genetic cross. In guinea pigs, black hair color is dominant (B) and white hair color is recessive (b). What hair color are the guinea pigs' offspring? A All Black B All White C Mostly black with some white D Mostly white with some black Answer: C Mostly black with some white.

3 Grade 7 (2d Genetics) Students know plant and animal cells contain many thousands of different genes and typically have two copies of every gene. The two copies (or alleles) of the gene may or may not be identical, and one may be dominant in determining the phenotype while the other is recessive. (pg. 107 Science Framework) Summary: This standard introduces some principles of Mendelian genetics. The most significant concept is that genes exist in multiple versions, called alleles, and these units of heredity are not typically changed during mating. Using true-breeding strains of peas with a variation of a single gene (such as flower color), Mendel showed that the old model of blending was incorrect. Every person has tens of thousands of genes and that there are slight variations, or alleles, of these genes in every individual. Every person has every gene (and usually in two copies), but some people have an abnormal of different version (or versions) that can lead to a disorder or different trait. The genetic traits of an individual are determined by which alleles of genes are inherited from each parent and how those alleles work together. Some alleles are dominant, meaning that they overcome the influence of the other (recessive) alleles Florida Released Questions In one species of guinea pig, the gene for black fur is dominant while the gene for brown fur is recessive. A male guinea pig with black fur and a female guinea pig with black fur produce an offspring with brown fur. Which most likely describes the genes of the guinea pigs? A Both parent guinea pigs carry the recessive gene. B The male parent guinea pig carries the recessive gene, but the female parent does not. C The female parent guinea pig carries the recessive gene, but the male parent does not. D Neither parent guinea pig carries the recessive gene. The brown fur was a spontaneous mutation. Answer: A Both parent guinea pigs carry the recessive gene.

4 Rabbit Test Cross Results Parent Generation F 1 F 2 Black X White All Black 75% Black 25% White What conclusion can be drawn from the genetic information above? A. The white parent carried a dominant allele. B. All the F 1 rabbits carried a recessive allele. C. All the white rabbits are heterozygous. D. All the black rabbits in the F 2 generation are homozygous. Answer: B. All the F 1 rabbits carried a recessive allele. Mendel's early work with pea plants demonstrated a significant genetic discovery. The crossing of homozygous tall pea plants with homozygous short pea plants always resulted in tall plants and demonstrated that tallness in pea plants is a trait that is A blended B dominant C mutated D recessive Answer: B dominant Tennessee Released Question A cross between a red flowered plant (RR) and a white flowered plant (rr) is shown in the Punnett Square below: R Rr Rr R Rr Rr Which of the best describes the genotype of the offspring from this cross? A homozygous dominant B homozygous recessive C heterozygous dominant D heterozygous recessive Answer: D heterozygous recessive

5 Grade 7 (2e Genetics) Students know DNA (deoxyribonucleic acid) is the genetic material of living organisms and is located in the chromosomes of each cell. (pg. 108 Science Framework) Summary: Chromosomes in eukaryotes are complexes of DNA and protein. Chromosomes organize the genetic make-up of a cell into discrete units. The proteins in a chromosome help to support its structure and function, but the genetic information of a cell is uniquely stored in the DNA component of the chromosome. New York Released Question Hereditary information is found in a cell s A chloroplasts B chromosomes C cytoplasm D membranes Answer: B chromosomes The Human Genome Project was begun in 1988 by scientists from 13 nations as a worldwide effort to understand the sequencing of the entire DNA in the human body. What is one potential scientific of this research? A It will help to explain human cultural differences B It will create communication between research centers C It will help find the genes responsible for many diseases D It helps to classify man most accurately in the animal kingdom Answer: C It will help find the genes responsible for many diseases

6 Biology (2b Genetics) Students know only certain cells in a multicellular organism undergo meiosis. (pg. 225 Science Framework) Summary: Only special diploid cells, called spermatogonia in the testis of the male and oogonia in the female ovary, undergo meiotic divisions to produce the haploid sperm and haploid eggs. The processes of meiosis and fertilization help ensure the survival of the species by providing each generation with the same number of. A. body cells B. cromosomes C. offspring D. gametes Answer: B. chromosomes The jimsonweed Daterra stramonium normally has 12 chromosomes in the body cells. How many chromosomes will an egg cell of the jimsonweed have? A 6 chromosomes B 12 chromosomes C 18 chromosomes D 24 chromosomes Answer: A 6 chromosomes Biology (2d Genetics) Students know new combinations of alleles may be generated in a zygote through the fusion of male and female gametes (fertilization). (pg. 226 Science Framework) Summary: Once the gametes are formed, the second half of sexual reproduction can take place. In this process a diploid organism is reconstituted from two haploid parts. When a sperm is coupled with an egg, a fertilized egg (zygote) is produced that contains the combined genotypes of the parents to produce that contains the combined genotypes of the parents to produce a new allelic composition for the progeny. Students should be able to read the genetic diploid karyotype, or chromosomal makeup, of a fertilized egg and compare the allelic composition of progeny with the genotypes and phenotypes of the parents.

7 Biology (2e Genetics) Students know why approximately half of an individual s DNA sequence comes from each parent. (pg. 226 Science Framework) Summary: Chromosomes are composed of a single, very long molecule of doublestranded DNA and proteins. Genes are defined as segments of DNA that code for polypeptides (proteins). During fertilization half the DNA of the progeny comes from the gamete of one parent, and the other half comes from the gamete of the other parent. Biology (2f Genetics) Students know the role of chromosomes in determining an individual s sex. (pg. 226 Science Framework) Summary: The normal human somatic cell contains 46 chromosomes, of which 44 are pairs of homologous chromosomes and 2 are sex chromosomes. Females usually carry two X chromosomes, and males possess one X and a smaller Y chromosome. Combinations of these two sex chromosomes determine the sex of the progeny. Biology (3a Genetics) Students know how to predict the probable outcome of phenotypes in a genetic cross from the genotypes of the parents and mode of inheritance (autosomal or X-linked, dominant or recessive). (pg. 227 Science Framework) Summary: Monohybrid crosses, including autosomal dominant alleles, autosomal recessive alleles, incomplete dominant alleles, and X-linked alleles, can be used to indicate the parental genotypes and phenotypes. The possible gametes derived from each parent are based on genotypic ratios and can be used to predict possible progeny. The predictive (probabilistic) methods for determining the outcome of genotypes and phenotypes in a genetic cross can be introduced by using Punnett Squares and probability mathematics. California Released Question If a corn plant has a genotype of Ttyy, what are the possible genetic combinations that could be present in a single grain of pollen from this plant? A Ty, ty B TY,ty C TY,Ty,ty D Ty, ty, ty, TY Answer: A Ty, ty

8 California Released Question In fruit flies, the gene for red eyes (R) is dominant and the gene for sepia eyes (r) is recessive. What are the possible combinations of genes in the offspring of two redeyed heterozygous flies (Rr)? A RR only B rr only C Rr and rr only D RR, Rr and rr only Answer: D RR, Rr and rr only California Released Questions In certain breeds of dogs, deafness is due to a recessive allele (d) of a particular gene, and normal hearing is due to its dominant allele (D). What percentage of the offspring of a normal heterozygous (Dd) dog and a deaf dog (dd) would be expected to have normal hearing? A 0% B 25% C 50% D 100% Answer: C 50%

9 California Released Questions Fur color in cats is controlled by an autosomal gene that can occur in the dominant form, (B), or the recessive form, (b). The length of the cat s fur is controlled by another autosomal gene which occurs in the dominant form, (S), or the recessive form, (s). The table below shows the traits for these allele codes. Gene Trait B black fur b white fur S short-haired fur s long-haired fur The following genotypes were found in a male cat and a female cat. BbSs (male) bbss (female) Which one of the following choices is true of the phenotype of offspring from these parents? A All offspring will have black fur. B All offspring will have white fur. C All offspring will have long-haired fur. D All offspring will have short-haired fur. Answer: D All offspring will have short-haired fur Illinois Released Question This is a diagram of a genetic cross. In guinea pigs, black hair color is dominant (B) and white hair color is recessive (b). What hair color are the guinea pig s offspring? B BB Bb b Bb bb A All black B All white C Mostly black with some white D Mostly white with some black Answer: C Mostly black with some white

10 New York Released Question T Tt Tt T Tt Tt In a certain plant, the gene for tall height (T) is dominant over the gene for short height (t). The Punnett square shows the results of a cross between a pure tall plant and a pure shot plant. Which process is represented by the use of the Punnett square? A natural selection B sexual reproduction C pollination D mutation Answer: B sexual reproduction A genetic pedigree showing that only males are affected by a certain disorder is evidence of what type of inheritance? A. dominant B. sex-linked C. recessive D. passive Answer: B. sex-linked G GG Gg g Gg Gg In corn plants, green (G) is dominant to albino (g). According to the Punnett square, what is the chance of this heterozygous cross producing an albino corn plant? A one in four B two in four C three in four D four in four Answer: A one in four

11 Biology (5a Genetics) Students know the general structures and functions of DNA, RNA, and protein. (pg Science Framework) Summary: Nucleic acids are polymers composed of monomers called nucleotides. Each nucleotide consists of three subunits: a five-carbon pentose sugar, a phosphoric acid group, and one of four nitrogen bases. DNA and RNA differ in a number of major ways. A DNA nucleotide contains a deoxyribose sugar, but RNA contains ribose sugar. The nitrogen bases in RNA are the same as those in DNA except that thymine is replaced by uracil. RNA consists of only one strand of nucleotides instead of two as in DNA. Proteins are polymers composed of amino acid monomers. Different types of proteins function as enzymes and transport molecules, hormones, structural components of the cells, and antibodies that fight infection.