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Bio-121 > Unit 1 Learning Objectives > Flashcards

Unit 1 Learning Objectives Flashcards

1
Q

•Describe the four characteristics of living things

A

Complex, change in response to the environment, reproduce, evolve

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2
Q

•Define a cell

A

The simplest self-replicating entity that can exist as an independent unit of life

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3
Q

Describe the three essential features of all cells

A
  1. Store & transmit info
  2. Plasma membrane
  3. Harness energy from the environment
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4
Q

Explain the Central Dogma

A

DNA → (transcription) RNA →(translation) protein

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5
Q

•Define matter and element

A

Matter = anything that takes up space & has mass
Element = fundamental substances in nature; 94 naturally occur; cannot be broken down by chemical reactions

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6
Q

Know the four most abundant elements in the human body

A

Carbon, nitrogen, oxygen, hydrogen

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7
Q

Know the structure of an atom and the function of its 3 subatomic particles (protons, neutrons, electrons)

A

Neutron = neutral charge; contribute to mass
Proton = positive charge; contribute to mass
Electron = negative charge; negligible mass

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8
Q

Differentiate between an atom’s atomic number and atomic mass

A

Atomic number = number of protons
Atomic mass = number of protons and neutrons

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9
Q

Define an isotope and an ion and differentiate between the two

A

Isotope = two atoms of an element that differ in number of neutrons
Ion = Atoms that gain or lose an electron become charged

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10
Q

Explain electron orbitals

A

Regions of space where an electron spends most of its time

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11
Q

Describe the 4 types of chemical bonds used to make molecules

A

Covalent bond = equal sharing of electrons
Polar covalent bond = unequal sharing of electrons; depends on electronegativity of an atom
Hydrogen bond = interaction between Hydrogen and an electronegative atom; partial negative is attracted to partial positive
Ionic bond = interaction between oppositely charged ions; metal + nonmetal

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12
Q

Differentiate between covalent and polar covalent bonds

A

Covalent = equal sharing of electrons
Polar covalent = unequal sharing of electrons

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13
Q

Describe the properties of water that make it indispensable to life on earth

A

Polar molecule
Good solvent
pH of 7

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14
Q

Describe the interaction between the atoms of a single molecule of water, and among water molecules

A

Single molecule → polar covalent bonds
Multiple molecules → hydrogen bonds

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15
Q

Correlate water’s high specific heat with its ability to stabilize temperature fluctuations

A

Water changes its temperature less when it absorbs or releases a given amount of heat
High specific heat → result of hydrogen bonds

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16
Q

Define solution, solute, solvent, aqueous solution

A

Solution = a liquid that is a homogeneous mixture of substances
Solvent = the dissolving agent of a solution
Solute = the substance that is dissolved
Aqueous solution = one in which water is the solvent

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17
Q

Differentiate between hydrophilic and hydrophobic substances

A

Hydrophilic = has an affinity for water; a substance can be hydrophilic without actually dissolving
Example → cotton
Hydrophobic = does not have an affinity for water; cannot form hydrogen bonds
Example → vegetable oil

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18
Q

Correlate changes in hydrogen ion concentration (H+) with pH

A

Acid → increases (H+) and reduces pH
Base → reduces (H+) and increases pH

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19
Q

Describe the bonding properties of Carbon that relate to its structural diversity

A

Carbon atom behaves as if it has 4 unpaired electrons
Forms covalent bonds
Carbon forms a tetrahedron when covalently bound to 4 other atoms

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20
Q

Define an isomer

A

Molecules with the same chemical formula can arrange differently
Different structures
Different functions

21
Q

Describe the basic structure of an amino acid

A

Amino group
Carbon (alpha)
R group
Carboxyl group

22
Q

Describe how amino acids link together via peptide bonds to form proteins

A

Carbon of the carboxyl group of one amino acid is linked to the nitrogen in the adjacent amino group by a covalent peptide bond
Water is lost (dehydration reaction)

23
Q

Identify and Define the three components of a nucleic acid

A

5-Carbon sugar (ribose or deoxyribose)
Ribose = RNA ,Two hydroxyl groups
Deoxyribose = DNA,One hydroxyl group (none on 2’ Carbon)

Base containing nitrogen
Attached to 1’ Carbon
RNA = A,G,U,C
DNA = A,G,T,C

One or more phosphate groups
Makes nucleic acid negative
Attached to 5’ Carbon

24
Q

Describe the difference between a deoxyribonucleotide and a ribonucleotide

A

Deoxyribonucleotide → has only 1 hydroxyl group on 3’ carbon
Ribonucleotide → has 2 hydroxyl groups; one on 3’ carbon and one on 2’ carbon

25
Q

Identify the five nitrogen-containing bases of nucleic acids and differentiate between the two classes (purines and pyrimidines)

A

Pyrimidines (one ring structure)
Thymine (T)
Cytosine (C)
Uracil (U)
Purines (double ring structure)
Adenine (A)
Guanine (G)

26
Q

Describe the process of nucleotide joining

A

Phosphodiester bond
5’ phosphate group of one nucleotide binds to the 3’ OH group on the sugar of another nucleotide
Results in the loss of water (dehydration reaction)

27
Q

Describe the structure of DNA

A

Double helix = 2 strands of nucleotides twisted around each other
Sugar phosphate backbone
Complementary base-pairing
Bases connected by hydrogen bonds

28
Q

Define a carbohydrate and identify/describe the two main classes of sugars

A

Simple carbohydrates = monosaccharides
-Exist as linear or cyclical structures
-Composed of Carbon, Hydrogen, & Oxygen
-Contain 5 or 6 carbons

Two main classes :
1. Ketose = contain ketone group
2. Aldose = contain aldehyde group

29
Q

Define Mono- Di- and Poly- saccharides

A

Monosaccharides = one sugar
Disaccharides = two sugars linked together by glycosidic bond
Polysaccharides = many sugars linked together

30
Q

Describe the cyclization process of ketose and aldose sugars

A

Rearrangement of atoms → NOT loss of atoms
Carbon in aldehyde forms a covalent bond w/ the oxygen of the -OH of another carbon in the same molecule

31
Q

Describe the process of glyosidic bond formation

A

Involves interaction of adjacent hydroxyl groups
Loss of water

32
Q

Identify the major difference between lipids and the other three classes of biomolecules

A

NOT defined by physical structure → defined by hydrophobic nature

33
Q

Describe and compare the three types of lipids

A

Fatty acids (triacylglycerol) = long carbon chains attached to a hydroxyl group
Chains linked by nonpolar covalent bonds
Steroids = carbon rings
Nonpolar covalent bonds → hydrophobic

Phospholipids = glycerol backbone + 2 fatty acid chains + phosphate head group
Hydrophobic & hydrophilic

34
Q

Describe the formation of a triacylglycerol

A

Glycerol’s 3 hydroxyl (-OH) groups covalently bind to the carboxyl group (-COOH) of three fatty acids

35
Q

Compare saturated vs unsaturated fats

A

Saturated = made up of fatty acids that DO NOT contain C=C bonds (saturated w/ hydrogen atoms)
Unsaturated = made up of fatty acids that contain C=C bonds
Kinks caused by C=C bonds:
Reduce tightness of packing
Lower melting temp @ RT

36
Q

Define Van der Waals forces and describe their role in lipid structure

A

Definition = regions of slight charges caused by constant motion of electrons
Role = attract & repel molecules; stabilize molecules

37
Q

Describe the structure and function of a phospholipid

A

Structure: Glycerol attached to 2 fatty acids and a phosphate-containing head group
Function: Major component of cell membrane

38
Q

Describe the RNA world hypothesis and the reasons why RNA is thought to be the original information storage molecule

A

RNA was the information storage molecule in early life forms
Evidence
RNA is used in replication, transcription, and translation
RNA has evolved over time
RNA can act as a catalyst

39
Q

Know the similarities and differences between RNA and DNA

A

RNA
Ribose
A,U,C,G
5’ end is triphosphate
Smaller
Single stranded

DNA
Deoxyribose
A, T, C, G
Monophosphate
Very large
Double stranded

40
Q

Describe template and nontemplate strands of DNA

A

Template strand → used as a template for RNA transcription
Nontemplate strand → other strand NOT used for RNA transcription

41
Q

Know the key features of transcription

A

RNA Polymerase = enzyme used for RNA synthesis
The new RNA stand grows in the 5’ → 3’ direction
The template DNA strand is in the 3’ → 5’ direction
Uracil containing nucleotides are inserted in RNA when there is an Adenine in the template strand

42
Q

Describe the process of transcription initiation including all factors involved

A

RNA polymerase & associated proteins bind DNA at promoter sequences
Eukaryotic promoters contain a sequence similar to TATAAA: TATA box
The first nucleotide to be transcribed is positioned ~25 base pairs from the TATA box

43
Q

Describe the process of transcription termination and all factors involved

A

RNA polymerase moves along the template strand until it encounters a terminator sequence

44
Q

Know and compare promoter recognition in prokaryotes and eukaryotes

A

Prokaryotes → Sigma factor proteins
Associates with RNA polymerase
Facilitates binding of RNA polymerase to promoters to initiate transcription

Eukaryotes → General transcription factor proteins
General transcription factor proteins recruit RNA polymerase II (Pol II) to the promoter
Proteins bound to an Enhancer sequence recruit a Mediator complex that interacts with the Pol II complex to initiate transcription

45
Q

Describe the functions of RNA Polymerase during transcription

A

Enzyme used for RNA synthesis

Steps
Separates the DNA
Synthesizes the RNA
Releases the finished transcript
Restores the DNA double helix

46
Q

•Describe the RNA polymerization reaction

A

Incoming ribonucleotides are accepted if they correctly base pair with the template DNA
The 3’ -OH of the growing strand attacks the high-energy phosphate bond of the incoming ribonucleotide, providing the energy to drive the reaction
The two phosphates of the incoming ribonucleotide are released as pyrophosphate

47
Q

Know and compare the RNA processing events that occur in prokaryotes and eukaryotes

A

Prokaryotes
The primary transcript is the mRNA
mRNA includes info needed to direct the ribosome to produce a protein (translation)
Transcription & translation both occur in the cytoplasm
Primary transcripts contain the information for more than one gene: Polycistronic mRNA

Eukaryotes
Nuclear membrane = barrier between transcription and translation
RNA processing = the primary transcript undergoes chemical modifications
3 types of chemical modifications occur before an mRNA is translated by the ribosome
5’ cap addition
3’ poly A tail addition
Splicing

48
Q

Describe the process of RNA splicing

A

Excision of introns & joining together of exons
Spliceosome: protein complex that catalyzes the intron removal
Splicing: binding of Spliceosome to sequences at the ends of introns & subsequent cutting of one end of the introm to form a loop (Lariat)
The exon on one end of the intron is joined to the exon at the other end and the intron (lariat) is released and broken down

Bio-121 (14 decks)

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