DNA, Chromosomes, and Genes Lab Report

LAB 10 REPORT SHEET DIRECTIONS Read the protocol for lab 10 and use it to answer the questions in this report sheet. You will be graded the same as you have on previous report sheets: 5pts – Great! No major errors and problems. 4pts – Satisfactory. Some errors, but mostly minor. 3pts – Needs work. More than one major error. 0pts – Not completed. EXERCISE 10.1 1. What is DNA? Give three characteristics of DNA. DNA, which stands for deoxyribonucleic acid, is the carrier of genetic information, the blueprint of life. Three characteristics of DNA include: - Two strands joined together through complimentary base pair - Adenine (A), guanine (G), cytosine (C) and thymine (T) are all four nitrogen bases used to make up DNA coding - DNA is coiled up into chromosomes in the nucleus of a cell 2. How many chromosomes are in each cell in your body? Is this cell haploid or diploid? How many of those chromosomes came from each of your parents? Each body cell has a total of 46 chromosomes. The cell is diploid, meaning it contains two copies of each chromosome. 23 chromosomes each come from both your parents. 3. What is meant by homologous chromosomes? Each pair of chromosomes share the same gene pattern. 4. Define gene. A gene is a segment of DNA that contains instructions for making at least one protein. EXERCISE 10.2 Match each term to its definition in the table below. A B C D E F G H I Homozygous Fertilization Genotypes Allele Dominant Heterozygous Phenotypes Recessive Gametes Definition Inheritance of two different allele Alternative forms of a gene Eggs or sperm cells are called Union of an egg and sperm to produce a zygote Allele that has no noticeable effect in a heterozygote Organism’s physical appearance Inheritance of the same two alleles Allele that is fully expressed in an organism Genetic makeup of an organism Letter F D I B H G A E C EXERCISE 10.3A 5. How do we inherit traits? We inherit traits from our parents, in which each passes down one copy of each of their genes, thus making the offspring have 2 copies of every gene. The combined output from all of our genes influences inherited traits. 6. If you are a female, you have what pair of sex chromosomes? If you are male, you have what pair of sex chromosomes? Females have two X chromosomes (XX) and males have one X and one Y chromosome (XY). 7. Why is the inheritance of traits considered random and unique? It is random and unique because each child gets a unique combination of copies of all of their parents’ genes, which is genetic variation. Unique gene combinations give each individual a unique set of inherited characteristics. EXERCISE 10.3B 8. Give two examples of traits that are determined by genetics. Two examples of traits determined by genetics include eye color and nose shape. 9. Give two examples of traits that largely/entirely determined by environmental conditions. Two examples of traits that are largely/entirely determined by environmental conditions include the language we speak and the music we like. 10. Explain how a trait can be affected by BOTH genetics and the environment. There could be a trait that we inherit from our parents, but that trait also needs a boost from the environment. For instance, height is a trait that is inherited from two parents, but in addition to inheriting those genes, one must also have a good nutrition value simply by eating healthy and feeding cells what they need in order to grow. EXERCISE 10.4 Complete the table below following the directions in the protocol. Dominant observed trait Have detached earlobes Ability to roll tongue Your phenotype Detached earlobes No tongue rolling Your possible genotype(s) Survey four people. How many have the dominant trait? % of people (including you) with the dominant phenotype EE or Ee 4 100% tt 0 0% Have dimples No dimples dd 0 0% Right-handed Left-handed hh 2 50% ff Have freckles No freckles Have curly hair Have Curly Hair 0 Left thumb on top when interlocking hands Right thumb on top ii Are NOT colorblind Not colorblind BB or Bb 0 0% Have a widow’s peak No widow’s peak ww 1 25% CC or Cc 0% 4 0 100% 0%