exam 1

Question 1

Describe the characteristics of life.

Answer 1

1. Cell and organization: each cell can only perform the job of its function.
2. Energy use and metabolism: to maintain their internal order, energy is needed by organisms. Energy is utilized in chemical reactions.
3. Response to environmental changes
   responds to stimulation
4. Regulation and homeostasis: internal regulation of our body to maintain a stable environment
5. Growth and development: all living things get larger and more complex throughout the organism’s life
6. Reproduction
7. Biological evolution: the change over time of living organisms

Question 2

List and describe the 3 biological domains.

Answer 2

Bacteria
Archaea
Eukarya

Question 3

List and describe the kingdoms belonging to Domain Eukarya.

Answer 3

Protista, Fungi, Plantae, and Animalia. Eukaryota consists of organisms that have a true nucleus and structures called organelles that are surrounded by membranes.

Question 4

What’s the difference between a hypothesis, theory, and law.

Answer 4

A hypothesis is a brief explanation of a phenomenon. A theory is an in-depth explanation of an observed phenomenon. A law is a statement of a phenomenon.

Question 5

What’s the difference between an independent variable and dependent variable?

Answer 5

The independent variable can be changed and manipulated. The dependent cannot be changed or manipulated.

Question 6

Apply theory of evolution by natural selection.

Answer 6

Natural selection is individuals with inherited traits that are better suited to the local environments and are more likely to survive and reproduce.

Question 7

Describe the 7 themes unifying biology.

Answer 7

1. Cell theory: all life consists of cells.
2. Inheritance: DNA contains info specifying characteristics of cell.
3. Structure/ function: structure indicates function and vice versa.
4. Diversity of Life is due to evolution.
5. Unity of Life is due to evolution
6. Cell process info: sense and respond to environment.
7. Living Systems exist in non equilibrium state: organisms need constant supply of energy (sun); self organization

Question 8

Describe structure of an atom in detail.

Answer 8

All matter is made up of atom. In the center of the atom is the nucleus which is a cluster of protons and neutrons. The protons have a positive electric charge while the neutrons are electrically neutral. The nucleus makes up almost all of an atom’s mass or weight.

Question 9

Compare and contrast different chemical bonds and describe their characteristics (covalent, ionic, hydrogen, van der waals)

Answer 9

Covalent bonds form when 2 atoms share one or more pairs of valence. Ionic bonds form when 2 atoms are attracted to each other by opposite charge. Hydrogen bonds occur when partially positive hydrogen of one polar molecular is attracted to the partially negative end of another. Van der waals force is the attraction between molecules due to non symmetrical distribution.

Question 10

Compare polar and nonpolar bonds.

Answer 10

Polar bonds are electrons shared equally. Nonpolar bonds are shared unequally.

Question 11

Describe chemical reaction and the 3 factors that effect it.

Answer 11

Chemical reactions is making and breaking of chemical bonds. The 3 factors that effect reaction is temperature, concentration, and catalyst.

Question 12

Describe the properties of water.

Answer 12

One molecule of water has two hydrogen atoms covalently bonded to a single oxygen atom.

Question 13

Compare hydrophilic and hydrophobic.

Answer 13

Hydrophilic molecules whose interactions with water are thermodynamically favorable and are capable of hydrogen bonding.
Hydrophobic molecules don’t mix with water (oils, fats, grease)

Question 14

Describe the importance of buffers and how they function in maintaining pH.

Answer 14

Buffers are the substance that minimizes changes in the concentration of H+ and OH- in a solution. Most contain a weak acid and its corresponding base. It is a solution that that resists a change in PH when acids or bases are added.

Question 15

Define organic chemistry.

Answer 15

Organic chemistry is the chemistry of carbon compounds.

Question 16

Describe the properties of carbon and how they result in carbon being the framework of biological molecules.

Answer 16

All living things contain carbon in some form.
Carbon is the primary component of macromolecules, including proteins, lipids, nucleic acids, and carbohydrates.
Carbon’s molecular structure allows it to bond in many different ways and with many different elements.
The carbon cycle shows how carbon moves through the living and non-living parts of the environment.

Question 17

Describe and identify hydrocarbons.

Answer 17

A hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls.

Question 18

Describe the 4 macromolecules, how they are formed, how they get their structure, and their major functions.

Answer 18

Carbohydrates function is for fuel, energy storage and building material. They are formed from molecular compounds made from carbon, hydrogen, and oxygen. Monosaccharides (can be active alone. Disaccharide consists of two monosaccharides (sucrose= glucose + fructose). Polysaccharides consists of more than two monosaccharides.
Lipids are mostly hydrophobic, insoluble in water. Most common lipids are fats, phospolipids and steroids.
Proteins do the work of the cell, the shape of the protein determines the structure.
Nucleic acids include DNA and RNA and are made of nucleotides and have a 5-carbon sugar, a phosphate group, and a nitrogenous base.

Question 19

Describe the Griffith Experiment.

Answer 19

Frederick Griffith studied bacteria that can cause pneumonia. Virulent strain (S form) has a polysaccharide coat and causes death and disease in mice. A nonvirulent strain (R form) does not have a polysaccharide coat and does not cause death and disease in mice. The live S form was injected into mice, they got disease and died. The live R form was injected into mice and the mice lived. A heat-killed S form was injected into mice and they lived. A heat-killed S and live R form was injected into the mice and they died.
Conclusion: information specifying the polysaccharide coat had passed from dead S form to live R form. The “transformation” R form now produce a polysaccharide coat and are classified as S form.

Question 20

Describe the Hershey and Chase Experiment.

Answer 20

They studied viruses that infect bacteria (bacteriophage). Bacteriophage consists of a protein coat surrounding DNA. Bacteriophage inject their genetic material into bacterial cell and bacterial cells use this info to make more phage. The goal of their expieriment was to determine whether protein or DNA is the genetic material that is injected into the bacteria by virus.

Question 21

Describe Chargaff’s rules.

Answer 21

Erwin Chargaff studied proportions of Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). He determined that the proportions of bases varied between sources of DNA. When studying a single DNA molecule he determined that A=T and C=G

Question 22

Describe Watson, Crick, Wilkins, and Franklin’s roles in describing structure of DNA.

Answer 22

Rosalind Franklin performed x-ray diffraction studies to identify the 3-d structure. She discovered that DNA is helical. She used Maurice Wilkin’s DNA fibers and discovered that the molecule has a diameter of 2nm and makes a complete turn of the helix every 3.4nm.
James Watson and Francis Crick deduced that the structure of DNA using evidence from Chargaff, Franklin, and others. Found out that DNA is a double helix form. Also found out that two strands are complementary to each other (A pairs with T, G pairs with C). They did not perform a single experiment themselves related to DNA.

Question 23

Describe how anti-parallel orientation and 5’ 3’ end difference influences the processes of replication.

Answer 23

The primary function of DNA is to store and transmit genetic information. To accomplish this function DNA must have two properties. It must be chemically stable so as to reduce the possibility of damage. DNA must also be capable of copying the information it contains. The two-stranded structure of DNA gives it both of these properties. The nucleotide sequence contains the information found in DNA. The nucleotides connect the two strands through hydrogen bonds. Because each nucleotide has a unique complimentary nucleotide, each strand contains all the information required to synthesize a new DNA molecule. The double stranded structure also makes the molecule more stable.

Question 24

List and describe the activities performed by DNA polymerase.

Answer 24

DNA polymerase matches existing DNA bases with complementary nucleotides and links them. It adds new nucleotides to the 3’ end of the existing strand. It makes DNA in 5’ to 3’ direction. It cannot link 1st two nucelotides together because it needs a primer.

ex: 5’ATGGTAC3’
3’TACCATG5’
they are complementary to each other.

Question 25

Identify and describe the 3 types of RNA.

Answer 25

• Messenger (mRNA) carries genetic information needed to make polypeptide.
• Ribosomal (rNA) serves as a structural role as framework for ribosome (ribosomes make protein).
• Transfer (tRNA) delivers amino acid to ribosome for assembly into proteins

Question 26

Identify the enzyme used and the structural features of the DNA region which are important in the process of transcription.

Answer 26

DNA polymerase.

• uses DNA template strand to make complementary RNA strand
• Can link 2 nucleotides together;doesn’t need a primer

Question 27

Identify the steps in translation.

Answer 27

3 steps:

• initiation: begins at start codon
• elongation: growing poypeptide chain
• termination: halts at stop codon

Question 28

Describe the roles of codon and anticodon and the functions of RNA’s involved.

Answer 28

Codons code for the peptide sequence. Anticodons is on the tip and link the correct amino acid.

Question 29

Explain the genetic code.

Answer 29

The genetic code is the set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins (amino acid sequences) by living cells.

Question 30

What does this phrase mean, “the genetic code is degenerate”?

Answer 30

The genetic code is degenerate because more than one codon sequence can code for the same amino acid.

Question 31

tRNA:

Answer 31

Carry amino acids to ribosome for incorporation into a polypeptide
Amino acid is added to acceptor stem of tRNA
Anticodon loop has 3 nt complementary to mRNA codons

Question 32

What is point mutation and framework mutation?

Answer 32

Point mutation change 1nt pair in gene. 3 types
Silent mutation: does not change amino acid sequence of polypeptide
Missense mutation: changes one amino acid in polypeptide
Nonsense mutation: creates a premature stop codon
Framework mutation is the Addition or deletion of single nt
More profound consequences
Changes reading frame downstream

Question 33

Where does the independent variable and dependent variable go on a graph?

Answer 33

The independent variable goes on the bottom (x axis) and the dependent variable goes on the side (y axis)

Question 34

What are these graphs used for: line graph, scatter plot, bar graph, pie chart?

Answer 34

Line graphs can be used to compare changes over the same period of time for more than one group.

Scatter plots show how much one variable is affected by another. The relationship between two variables is called their correlation.

Bar graphs are used to compare things between different groups or to track changes over time, the bars do NOT touch.

Pie charts are best to use when you are trying to compare parts of a whole.

Question 35

Why is water a polar molecule?

Answer 35

A water molecule, because of its shape, is a polar molecule. That is, it has one side that is positively charged and one side that is negatively charged. The molecule is made up of two hydrogen atoms and one oxygen atom. The bonds between the atoms are called covalent bonds, because the atoms share electrons.

Question 36

What chemical groups are most important to life?

Answer 36

There are 7 important functional groups in the chemistry of life: Hydroxyl, Carbonyl, Carboxyl, Amino, Thiol, Phosphate, and aldehyde groups.

Question 37

Explain unity and diversity of life.

Answer 37

In biology the diversity and unity of life simply means that all living things came from ONE organism, so we are all alike but different. Then the diversity because even though we have come from the same organism but from a different branch of the tree of life.