Human Biology
Week 1: Worksheet

1. Consider the organization of life. Identify the different levels of organization from the cell to the organism.
-The cell is the smallest unit displaying the properties of life that is the basic structural and functional unit of organisms.
-Tissues are a group of similar cells that performs similar functions.
- Organ is a structure that contains at least two different types of tissues that work together for a common purpose.
-Organ system is a group of organs arranged in such a way that they perform functions that they would not otherwise be able to perform if they were by themselves.
-Organism is an individual being that contains all of the above mentioned. Without these an organism would not be able to function properly.
2. List and define the characteristics of life and provide an example in your life that demonstrates the characteristic.
-There are 7 characteristics of life and they are as follows: Organization is when single cell organisms have a specific make up to be self sufficient. It starts with an organism which is complex. Humans are classified as multicellular because they are composed of many different types of cells. A tissue is defined as a group of similar cells that perform a particular function. An organ is made up of many tissues, and organ systems are a group of organs that perform a common function. One example of life is humans.
When acquiring materials and energy, living things take in energy and use it for maintenance and growth. Humans eat plants and animals they raise for food to gain materials and energy as well as vitamins.
Reproducing occurs when a new individual organism is produced and formed. This process needs to happen for species not to become extinct. There are two types of reproduction asexual and sexual. Asexual reproduction is producing an offspring without the use of gametes. Sexual reproduction is producing an offspring by the joining of sex cells.
Growth and development is where you can see an increase in size which is recognized by the increase of cells. Growth starts from the time an organism is being created until the time it dies.
Being homeostatic is when an organism’s body temperature is able to maintain a normal temperature range. The different systems of the body help to maintain homeostasis. Without homeostasis when the external temperatures get too hot or too cold you would die from overheating or freezing.
Responding to stimuli is when an organism reacts to things. Whether it is from hearing something that is very loud, moving away or toward something that is beneficial for you. An example of this is when you are attempting to drink a hot liquid and it touches your tongue. Your nervous system reacts to it being too hot for you.
Evolution is the process by which species change through time. A change in species is called adaptation. If you get stuck on an island where there is only small animals and trees/ plants, even though you are not used to eating these things in order to survive you will have to adapt to your environment and eat what you can in order to survive.
3. Define biosphere.
-The zone (air, land, and water) on the Earth’s surface where living things exist.
4. What is the purpose of the scientific method?
-To clearly perform an experiment by means of a process by gaining knowledge through observations, documenting mistakes or errors and to correct them to show others how you came up with your results by performing an experiment, then testing the results.
5. List and explain the steps of the scientific method.
-Making an observation: begin by asking a question using the words when, why, where, which, what, or how in regards to something that has been observed. Gather some information and confirm that any past errors that were found do not get reported.
-Constructing a hypothesis: an educated guess through observation and experimentation of how the process occurs.
-Carrying out experiments and observations: Testing the hypothesis by conducting experiments through further observations and analyzing the data so you can deduce a conclusion
-Conclusion: you have to communicate the results of your experiment and the hypothesis to others through a display board or by publishing a final project.
-Developing a scientific theory: this would be done through lots of experiments, observations, and conclusions
6. In a controlled experiment, what is the difference between a control group and the experimental group. Give an example.
-A control group is a group that is not exposed to the factor that is being tested. They are not manipulated whereas in an experimental group the subjects are being treated or manipulated for the purpose of the experiment. For example in a study of 10 women being on a particular diet pill over a period of time, all around the same ages, and weight, 5 of the women were given a placebo (a harmless pill without medication in it) and the other 5 women were given the diet pill. The women that were given the placebo would be the control group and the women that were given the actual diet pill would be the experiment group.
7. Identify the 3 domains of living things.
-Eukarya, Archaea, and Bacteria
8. Two scientific studies have different probability values associated with their results. Study A has p = 0.5 whereas Study B has a p = .001. Which study shows the greater confidence level that the results were not due to chance? Explain your answer.
-Study A p=0.5 shows a greater confidence level that the results were not due to chance because it has a greater percentage than p=0.001 which shows that it was tested and could come out with 0.5 which shows greater confidence.
9. What is the difference between elements and compounds?
-Elements consist of singular atoms and cannot be made into anything simpler by means of chemical reactions whereas compounds are substances that are composed of several different kinds of atoms and can be broken down by means of chemical reaction.
10. What are the subunits of atoms and what are their electrical charges?
-Electrons have a negative charge, protons have a positive charge, and neutrons have a neutral charge.
11. What is the difference between ionic and covalent bonding?
-Ionic bonding is a chemical bond between 1 or more electrons from 1 atom being removed and attached to another atom resulting in a positive and negative charge that attracts each other whereas in covalent bonding atoms share 1 pair of electrons.
12. If a solution has a pH of 4 it would be considered a(n) _________.
-acid
13. List the 4 macromolecules and their functions. -Lipids contain fats and oils and have more energy per gram than other biological molecules so fats in animals and oils in plants function well as energy storage molecules.
- Carbohydrates are used for quick and short-term energy storage in all living things. It includes monosaccharides, disaccharides, and polysaccharides.
-Nucleic acids are a group of complex compounds found in all living cells and viruses composed of pyrimides, carbohydrates, and phosphoric acid. There are 2 types of nucleic acids DNA (deoxyribononucleic acid) and RNA (ribonucleic acid). Nucleic acids in the form of DNA and RNA control cellular function and heredity.
-Proteins are the primary importance in the structure and function of cells. Some proteins are structural and support the body, some are enzymes that bring reactants together to speed up the chemical reaction in cells, some transport proteins in the plasma membrane to allow substances to enter and exit cells. Proteins also function as defense antibodies to prevent antigens from destroying cells and upsetting homeostasis. There are regulatory proteins called hormones that serve as intercellular messengers that influence the metabolism of cells and motion proteins that allow parts of cells to move and cause muscles to contract.

14. According to the text, is a diet that contains 60%-70% high fiber carbohydrates considered healthy. Explain why. -Yes, according to the American Heart Association and the Mayo Clinic because fiber promotes water absorption into fecal material and it also adds bulk. It prevents constipation because additional bulk stimulates movements of the large intestines and additional water makes stool easier to pass. It also combines with cholesterol in the small intestines and prevents it from being absorbed to protect against heart disease.
15. What is the difference between saturated fats, unsaturated fats and trans fats? Which is considered the healthiest? -Saturated fat is a type of food fat that is solid at room temperature; it raises blood cholesterol levels by interfering with the entry of cholesterol into cells causing cholesterol to remain in the bloodstream longer and to become a part of the plaque that builds up in the blood vessels. It has no double bonds between the carbon atoms; the chain is saturated with all the hydrogens it can hold. -Unsaturated fat is a fat that is liquid at room temperature; it has double bonds in the carbon chain wherever the number of hydrogens is less than two per carbon. -Trans fats are artificially created using vegetable oils; they are hydrogenated to make them semisolid. It is a common name for unsaturated fat with trans isomer fat. -According to the text unsaturated fats are considered to be the healthiest.
16. What is the purpose of ATP in our bodies? -It is a high energy molecule that carries energy to the cells. Energy that is released by ATP is used by cells to synthesize molecules such as proteins and carbohydrates; in muscle cells the energy is used for muscle contraction and in nerve cells it is used for the conduction of nerve impulses.
17. List 3 differences between RNA and DNA.
-In sugars RNA contains ribose whereas DNA contains deoxyribose; in bases RNA contains adenine, guanine, uracil, and cytosine whereas DNA contains adenine, guanine, thymine, and cytosine; in strands RNA is single-stranded whereas DNA is double-stranded.
18. What is meant by denaturation of a protein? What is a common example? -When a protein is altered from its native structure and undergoes an irreversible change in its shape. A common example is when you boil an egg; it goes from a liquid state inside its shell to an irreversible solid state inside of the shell.
19. What is a radioisotope and how can it be helpful in medicine? -A radioisotope is an unstable form of an atom that spontaneously emits radiation in the form of radioactive particles or radiant energy. It can be helpful in medicine for sterilizing objects, including foods. Radioisotopes detect molecular changes.
20. Explain the difference between ions and atoms. -Ions are charged particles that carry a negative or a positive charge of an atom depending on the number of protons versus electrons whereas atoms are the smallest part of an element that retains the chemical and physical properties of the element and is composed of protons, electrons, and neutrons.
21. Explain the meaning of polar molecules. What is a common example of a polar molecule? -A common example of a polar molecule is water because it has a mostly positive charge on one side and a mostly negative charge on the other side
22. Define a "calorie". -A unit of heat equal to the amount of heat required to raise the temperature of one kilogram of water by one degree at one atmosphere pressure.
23. What is the difference between bases and acids? -Bases are substances that either take up hydrogen ions or release hydroxide ions whereas acids are substances that dissociate in water, releasing hydrogen ions. On the pH scale an acid is below 7 and bases are above 7.
24. What is the function of a buffer? -A buffer is a substance that minimizes change in the acidity (pH) of a solution when a acid or base is added to a solution. They help keep the pH within normal limits because they are chemicals or combinations of chemicals that take up excess hydrogen ions or hydroxide ions.
25. Define organic molecules. Give an example. -Organic molecules are substances that are in the body that are essential to life; they contain carbon, hydrogen, and oxygen. Some examples of organic molecules are carbohydrates, proteins, lipids, and nucleic acids.
26. What is the difference between a dehydration reaction and a hydrolysis reaction? -Dehydration reaction is a synthesis reaction resulting in a covalent bond with the accompanying loss of water molecules (OH and an H) being removed as the molecules are formed whereas a hydrolysis reaction is the splitting of a compound by the addition of water, with the H+ being incorporated in one fragment and the OH- in the other.
27. What is a similarity and a difference between starch and glycogen? -Starch and glycogen are both readily stored forms of glucose in plants and animals. Starch has fewer side branches or chains than glycogen has.
28. What is atherosclerosis and what substance in our diet is associated with the condition? -Atherosclerosis is a stage of arteriosclerosis involving fatty deposits inside the arterial walls thus narrowing the arteries. It is a very slow progressive condition caused by the formation of lesions on the inside of blood vessels that can start during childhood. It is associated with cholesterol in our diet.
29. What are the levels of protein organization? Identify and define them. -Primary which refer to the linear sequence of amino acids in the protein joined by peptide bonds. -Secondary is the coiling or bending of the polypeptide into sheets taking on a certain orientation in space. -Tertiary is a protein’s final three-dimensional shape that involves the folding back of a molecule upon itself and held together by disulfide in bridges and hydrogen bonds. -Quaternary is the complex structure formed by the interaction of two or more polypeptide chains.
30. What is termed the "universal energy currency of cells"? -ATP, it refers to the molecule that all your cells use as their source of energy to complete chemical reactions.