exam 1 flashcards
info from chapters 1-5 for first exam
What characteristics do eukaryotic and prokaryotic cells have in common? How do they differ?
- All cells are enclosed by a membrane that regulates the passage of materials between the cell and its surroundings.
- All cells use DNA as their genetic information.
- A eukaryotic cell has membrane-enclosed organelles, while a prokaryotic cell, does not contain a nucleus or other membrane-enclosed organelles.
What types of organisms are prokaryotic? Where is their genetic material?
- Prokaryotic cells are found in two groups of single-celled microorganisms, bacteria (singular, bacterium) and archaea (singular, archaean).
- A prokaryotic cell lacks a nucleus or other membrane- enclosed organelles. Furthermore, prokaryotic cells are generally smaller than eukaryotic cells.
What types are eukaryotic? Where is their genetic material?
- All forms of life (except bacteria and archaea), including plants and animals, are composed of eukaryotic cells.
- A eukaryotic cell contains membrane-enclosed organelles. Some organelles, such as the DNA-containing nucleus, are found in the cells of all eukaryotes; other organelles are specific to particular cell types.
EX: Chloroplast
What is taxonomy? What are the taxonomic groups that we use to classify living organisms? Which group is more general? Which is least general?
Domain (more general) Kingdom Phylum Class Order Family Genus Species (least general)
State and give an example of the three domains of life. What is common about eukaryotes (plants, animals, fungi) and prokaryotes (bacteria and archaea)? How do they differ?
Bacteria (E. Coli), Archaea (Prokaryotes), and Eukarya (Animals); Eukaryotes have nucleus, prokaryotes do not
Compare positive and negative feedback mechanisms.
- Positive feedback: more product accumulates, process speeds up
- Negative feedback: more product accumulates, process slows down
What is a controlled experiment?
An experiment in which all the variables are compared to the control variable (CV never changes; ex: placebo)
What does it mean that a hypothesis must be testable and falsifiable?
Testable means being able to test it; falsifiable means it is possible for the hypothesis to be false by observation or experimentation
How are hypotheses and predictions related?
Hypothesis is an educated, testable guess and a prediction uses observable phenomena to make a future prediction
You are investigating what factors influence exam scores in your biology class. One factor you want to test is whether caffeine has a positive effect on exam scores. You divide the class into two groups: The first group does not have coffee before the exam. The second group drinks one cup of coffee before the exam. You then compare the exam scores.
- What could be the hypothesis here?
- What could be the prediction?
- Which is your independent variable?
- Which one is the dependent variable?
Caffeine consumption leads to better exam scores in students
If a student consumes coffee before an exam, they will get a better score
The coffee
The exam scores
What were Darwin’s main observations?
- Individuals of a species are not identical
- Traits are passed from generation to generation
- More offspring are born than can survive
- There will be variations between members of the same species
Describe what Darwin meant by “descent with modification” and “natural selection.”
Species change over time, give rise to new species, and share a common ancestor; natural selection is the favoritism of desirable traits.
What do we mean by unity of living organism? What are some similarities among different forms of life?
All living things share the same fundamental characteristics because they share a common ancestor (ex: homeostasis, reproduction, etc)
What is matter?
-Matter is anything that takes up space and has mass
What is an atom?
The smallest unit of matter that still retains the properties of an element.
What is an element? Which four elements make up 96% of human body mass?
-An element is a substance that cannot be broken down to other substances by chemical reactions. The four elements are Carbon, Nitrogen, Oxygen and Hydrogen.
What is compound? What kinds of bonds are needed? Provide examples of compounds
-Compound is a combination of two or more different elements combined in a fixed ratio. You need chemical bonds to make compounds, like a covalent bond, ionic bond or polar covalent. One example of a compound could be NaCl, which is sodium and chlorine combined.
What is molecule? What kinds of bonds are needed? Provide examples of molecules
-A molecule consists of two or more atoms held together by covalent bonds. They need either a single or double bond. An example of a compound is H2, or O2.
Describe these subatomic particles of the atom and how they interact with one another: proton; neutron, electron.
-Protons are positively charged atoms, neutrons are neutral, and electrons are negative. The neutrons and protons form the atomic nucleus. Electrons form a “cloud” of negative charge around the nucleus.
If a normal atom of an element has 8 protons:
- which element is it?
- how many electrons will it usually have?
- how many neutrons will it usually have?
- What is the element’s atomic number and atomic mass?
-8
-8
-8
Atomic Number: 8
Atomic Mass: 16 g/mol
If Cl has 17 electrons, 17 protons, and 18 neutrons, what is its atomic number? What about its mass number?
-Number: 17 ; Mass: 35
Describe electron shells.
-Electron shells are a grouping of electrons surrounding the nucleus of an atom. They are concentric circles that surround the atom.
What are valence electrons and how do they affect the bonding potential of an element?
-The electrons in the outermost shell are called valence electrons. If the valence shell is full, the element is chemically inert. Also, however many spaces are open in the valence shell of an element, that predicts how many bonds it will be able to form.
What are noble gases? Where are they in the periodic table?
-Noble gases are elements that are the most stable because their valence shells are completely full. They are also the most chemically unreactive.
What are isotopes?
- Isotopes are two atoms of an element that differ in the number of neutrons.
Describe covalent bonds. How do they form?
-Covalent bond is the sharing of a pair of valence electrons by to atoms. Covalent bonds form when two nonmetal atoms share a pair of electrons.
What is a polar versus nonpolar covalent bond? How do the properties of polar and nonpolar molecule differ?
-In a polar bond, the atoms do not share the electron equally. In a nonpolar bond, the atoms share the electron equally. In a polar bond, they will have an excess charge due to the imbalance of electronegativity of atoms. Polar molecules also have a high boiling point, melting point.
What is an ionic compound? How do they form?
- It is a compound composed of ions. An ionic compound is formed by ionic bonds.
What do you call an ion with a positive charge? How are they formed? Are some elements in the periodic table more likely to form positive ions than others? If so, why?
-An ion with a positive charge is a cation. Cations are formed by losing one or more electrons and gaining a positive charge. Most metals are shown to become positive ions fairly easily. They are easier to become positive because they have valence electrons in an S orbital.
What do you call an ion with a negative charge? How are they formed? Are some elements in the periodic table more likely to form negative ions than others? If so, why?
-An ion with a negative charge is an anion. They are formed by the addition of one or more electrons in the outer shell. Halogens form negative ions more easily than any other elements.
What is the composition of hydrogen (number of protons, neutrons, and electrons)?
-Hydrogen has 1 electron 1 proton and no neutrons.
How many protons and electrons are in a H+ ion? What about a H- ion?
-There is one proton and neutron, however there are no electrons. It is the opposite for the H- ion, there is one electron and no neutrons or protons.
What is a hydrogen bond? How does it form? Is it weaker or stronger than a covalent bond?
-A hydrogen bond is an attractive force between a partially positive charged hydrogen and a partially negative charged atom. (like oxygen or nitrogen) Hydrogen bonds are weaker than a covalent bond.
