BIO 171 Test 2 Learning Objectives, questions and answers| graded A+

BIO 171 Test 2 Learning Objectives, questions and answers| graded A+ Describe the characteristics/properties of all living things, including humans. (11.1) Order, sensitivity or response to stimuli, reproduction, adaptation, growth and development, regulation, homeostasis, and energy processing. Describe the levels of organization among living things, and be able to identify phenomena that occur at, or are examples of, each of the levels of organization. (11.2) Atom, molecule, organelle (nucleus), cells (blood cell), tissue (skin tissue), organs and organ systems (stomach, digestive system), organisms populations and communities (person in park, all people in park, all living things in park), ecosystem (central park), and biosphere (all ecosystems on earth). Describe at least one property of water that is involved in maintaining life. (12.1) The hydrogen bonds between water molecules give water the ability to hold heat better than other substances. Allows for temperature stabilization. Distinguish between acidic and basic conditions with regards to either pH or hydrogen ion concentration. (12.2) Acidic - high number of hydrogen ions, low pH (0-6.9) Basic - high number of hydrogen ions, high pH (7.1-14) Distinguish between hydrophobic and hydrophilic molecules and give an example of each. (12.3) Hydrophobic - non-polar compounds that won't dissolve in water (oils, fats). Hydrophilic - substance readily forms hydrogen bonds with water and dissolves (salt, sugar). List the 4 major biological molecules and one function of each. (12.4) 1. Carbohydrate - energy storage and structural support/protection 2. Lipids - provide insulation from the environment 3. Proteins - hormones control or regulate growth, development, metabolism, and reproduction 4. Nucleic Acid - carry genetic blueprint of a cell and instructions for functioning of cell. Describe the different levels of protein structure and how that changes upon denaturation. (12.5) 1. Primary protein structure - sequence of a chain of amino acids. 2. Secondary - hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern. 3. Tertiary - 3-D folding pattern of a protein due to side chain interactions. 4. Quaternary - protein consisting of more than one amino acid chain. If a protein is exposed to temp changes, pH, chemicals, the structure may change which is called denaturation. The structure is preserved so denaturation is often reversible. Explain how hydrogen bonds (polar, non-covalent) are involved DNA structure. (13.1) The complementary base pairs of guanine with cytosine and adenine with thymine connect to one another using hydrogen bonds. These hydrogen bonds between complementary nucleotides are what keeps the two strands of a DNA helix together. Describe where DNA is at in an animal cell. (13.2) DNA is located in the nucleus of an animal cell. Describe in words or diagrammatically the central dogma of the conversion of the DNA code into an amino acid code in the protein and be able to name the processes (transcription and translation) involved. (13.3) DNA is converted into RNA by transcription, RNA is converted into amino acid code by transcription. Describe the genetic code used to convert a nucleic acid sequence into an amino acid sequence. (13.4) ... Explain the colinear (primary structure) relationship between nucleic acid sequence and the amino acid sequence of a protein. (13.5) ... Compare and contrast the diversity of monomeric units for nucleic acids and proteins (i.e. bases vs amino acids - specifically the R-group of amino acids. (13.6) ... Name the two biomolecule classes that are common to all viruses. (14.1) Nucleic acid, either DNA or RNA, and a protein coat which encases the nucleic acid Describe the general structure of viruses and compare enveloped to non-enveloped viruses. (14.2) Nucleic acid core, outer protein coating or capsid, sometimes an outer envelope made of protein from the host cell, sometimes additional proteins and enzymes. Enveloped viruses have membranes derived from the host cell that surrounds the capsids, like HIV. Non-enveloped viruses are more resistant to change in temperature and pH, like polio or hep A. Explain the two features (characters) used to classify viruses (keep it simple). (14.3) Core genetic material and capsid design. Describe the steps involved in the influenza life cycle shown in figure 21.8 (COVID-19 is an influenza virus). (14.4) Viruses enter a host cell, nucleic acid is released into the cell and is available for replication and transcription, last stage is to release the new virions produced in the host organism, they infect adjacent cells and repeat the cycle. Explain the two general approaches used for prevention and treatment of viral infections. (14.5) Antiviral drugs or vaccines. Explain the additional scientific knowledge (unknown to Darwin at the time) that led to the modern synthesis of evolution (we introduced this in class 13). (15.1) The work of Gregor Mendel was rediscovered and described the basics of inheritance. Scientists integrated genetics and evolution to create modern synthesis - the understanding of the basics of inheritance. Modern synthesis describes how natural selection affects a population's genetic makeup and how this can result in gradual evolution. Explain why new flu vaccines are developed every year. (15.2) The flu virus evolves rapidly, so the vaccine developed to combat last year's strain will not be as effective this year. Scientists predict strains based on how they evolve over time and the past few seasons. Describe the components of the Hardy-Weinberg equation (symbols and what they represent). (15.3) The Hardy-Weinberg equation states that a population's allele and genotype frequencies are inherently stable, so neither the allele or genotypic frequencies would change. p represents the frequency of a particular allele (the frequency of yellow color, Y) q represents the frequency of another allele (the frequency of green color, y) p + q = 1, only 2 possible alleles in the population. P^2 + 2pq + q^2 = 1, frequency of all possible combinations Describe one of the forces (of 5 listed on p. 522) that changes allelic frequencies and thus evolution of a population. (15.4) Genetic drift in a population can eliminate an allele from a population by chance. Some individuals have more offspring than others by chance, like a male rabbit was in the right place at the right time to mate, or the wrong place at the wrong time and got eaten by a fox. Small populations are more susceptible to genetic drift. Explain why there is no perfect organisms shaped by evolution. (15.5) Natural selection can only select on existing variation in the population. So it is limited by a population's existing genetic variance. Natural selection is also limited because it works on the individual, not the allele level. So individuals carry both good and bad alleles. 1. Explain why, even though the DNA sequence/genome of body cells are the same, the cells can look much different (e.g. compare a skin cell to a muscle cell)? (16.1) Each cell does not expresses/turn on the same set of genes. Only a small subset of proteins is expressed in a cell. For the proteins to be expressed, the DNA must be transcribed into RNA, and the RNA translated into protein. Specialized proteins that make up the eye are only expressed in the eye, and proteins in the heart are only expressed in the heart. Describe the different ways that gene expression can be measured. (16.2) Chromatin remodeling - changes the way that DNA is associated with chromosomal histones, regulates transcription and translation. DNA methylation - developmental changes and gene silencing. Describe the different steps within the central dogma and after where gene expression can be modified. (16.3) Chromatin remodeling alters the chromosomal structure. If a gene is going to be transcribed, the histone proteins and DNA in the chromosomal region encoding that gene are modified to open the promoted region to allow transcription factors to bind and start transcription. Explain what is meant by epigenetic regulation of gene expression. (16.4) Epigenetics are heritable modifications in gene function without changes in the DNA sequence. Changes in epigenetic regulation can be detected in cancer. The enzymes HAT causes uncoiling of DNA, allowing genes to become accessible to transcription factors, allowing gene expression to occur. The enzymes HDAC causes a tight coiling of DNA. Explain possible mechanisms of and give some examples of how the environment affects gene expression. (16.5) Changes in the environment such as heat or UV light exposure can change gene expression. Because proteins are involved in every stage of gene regulation, the phosphorylation of a protein can alter accessibility to the chromosome, can alter translation, can change nuclear shuttling, can alter RNA stability, can modify translation, or can change post- translational modifications. Ex: E.coli acquires lactose from the local environment. If no lactose is present, Describe how mutations and population genetics make cancer treatment a challenge. (17.1) Cells with a Large cell size and high mutation rate are more likely to be resistant to cancer treatments. Explain why cells divide in a multicellular organism. (17.2) Cells divide to grow and develop, as well as repair and replace cells. Name the steps within interphase and the processes that occur within these steps. (17.3) · G1 Phase (first gap) - Cell accumulates building blocks of DNA, as well as energy reserves to complete the task of replicating each chromosome in the nucleus. · S Phase (synthesis of DNA) - DNA forms identical pairs of sister chromatids, the centrosome is duplicated and gives rise to the mitotic spindle. · G2 Phase (second gap) - Cell replenishes its energy stores and synthesizes proteins necessary for chromosome manipulation and movement. Describe factors that result in stopping cell cycle progression. (17.4) Cells that aren't big enough or have DNA damage. Some cells stay in an inactive stage until environmental conditions improve. Some cells like cardiac muscle or nerve cells never or rarely divide. Describe what happens to the cell when it does not "check" out. (17.5) A cell that does not pass a checkpoint will not be allowed into the next phase or will regress back into the previous stage until conditions improve. If the damage to the cell cannot be fixed the cell dies. Explain the role of proto-oncogenes in the cell cycle and oncogenes role in cancer. (17.6) The genes that code for the positive cell-cycle regulators are called proto-oncogenes. Proto-oncogenes are normal genes that, when mutated in certain ways, become oncogenes - genes that cause a cell to become cancerous. Explain the role of tumor suppressor genes in the cell cycle and how mutations in these genes result in cancer. (17.7) Tumor suppressor genes are segments of DNA that code for negative regulator proteins, the type of regulators that when activated can prevent the cell from undergoing uncontrolled division. They put up a roadblock to cell-cycle progression.