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Biology Flashcards

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1
Q

What kind of bonds create permanent dipoles in molecules?

A

Polar Covalent bonds

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2
Q

What is the driving force behind intermolecular forces and physical/chemical compounds of various functional groups?

A

Polarity

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3
Q

Order these molecules in terms of increasing polarity: Carboxylic Acids, charged molecules, alkanes, alcohols

A

Alkanes, alcohols, carboxylic acids, charged molecules

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4
Q

What effect can symmetrical polar bonds have on the overal polarity of a molecule?

A

Symmetrical polar bonds may result in an overal non-polar molecule

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5
Q

What four groups are bound to the central carbon atom in an amino acid?

A

-NH2, -COOH, -H, -R

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6
Q

What Amino Acids are nonpolar?

A

Glycine, Alanine, Valine, Isoleucine, Leucine, Methionine, Proline, Phenylalanine, Tyrosine, Tryptophan

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7
Q

What Amino Acids are polar, uncharged?

A

Serine, Threonine, asparagine, glutamine, Cysteine

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8
Q

What Amino Acids are positively charged/basic?

A

Arginine, Histidine, Lysine

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9
Q

What Amino Acids are negatively charged/acidic?

A

Aspartic Acid, Glutamic Acid

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10
Q
A

Glycine

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11
Q
A

Alanine

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12
Q
A

Valine

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13
Q
A

Leucine

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14
Q
A

Isoleucine

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15
Q
A

Methionine

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16
Q
A

Phenylalanine

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17
Q
A

Tryptophan

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18
Q
A

Proline

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19
Q
A

Serine

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20
Q
A

Threonine

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21
Q
A

Cysteine

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22
Q
A

Tyrosine

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23
Q
A

Asparagine

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24
Q
A

Glutamine

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25
Q
A

Aspartate

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26
Q
A

Glutamate

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27
Q
A

Lysine

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28
Q
A

Arginine

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29
Q
A

Histidine

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30
Q
A

Alkanes

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31
Q
A

Alkenes

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32
Q
A

Alkynes

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33
Q
A

Alkyl Halides

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34
Q
A

Alcohols

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35
Q
A

Ethers

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36
Q
A

Thiols

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37
Q
A

Amines

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38
Q
A

Imines

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39
Q
A

Aldehydes

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40
Q
A

Ketones

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41
Q
A

Carboxylic Acids

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42
Q
A

Esters

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43
Q
A

Lactone (cyclic ester)

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44
Q
A

Amides

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45
Q
A

Lactam (cyclic amide)

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46
Q
A

Thioesters

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47
Q
A

Anhydrides

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48
Q
A

Acyl Halides

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49
Q
A

Pyrrole

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50
Q
A

Imidazole

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51
Q

Primary Structure of Proteins

A

Amino Acid Sequence

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52
Q

Secondary Structure of Proteins

A

H-bonding between amino acid backbone components

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53
Q

Tertiary Structure of Proteins

A

Side chain interactions

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54
Q

Quaternary Structure of Proteins

A

Interactions between polypeptides

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55
Q

What kind of molecule is this?

A

Triglycerol (known for saponification process)

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56
Q
A

Phospholipid (known for bing major component of lipid bilayer in cell membranes)

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57
Q
A

Sphingolipid (Generally found on the outside of plasma membrane and play crucial role in signaling)

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58
Q

What are the 3 primary functions of Lipids?

A

Signaling, Structure, and Energy Storage

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59
Q

What are the primary functions of proteins?

A

Building blocks of body, structure and signaling

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60
Q
A

Cholesterol (contributes to fluidity of cell membrane)

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61
Q
A

Testosterone

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62
Q
A

Vitamin D

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63
Q
A

Prostaglandins (Well-known for the regulation of inflammation)

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64
Q

What is the difference between terpenes and terpenoids?

A

Terpenoids are terpenes that are modified with other organic substituents

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65
Q
A

Terpenes (made of isoprene units)

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66
Q

What are carbohydrates primarily known for?

A

Being a major source of energy (used in metabolism)

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67
Q
A

Glucose

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68
Q
A

Fructose

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69
Q
A

Galactose

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70
Q

What monosaccharides make up sucrose (a disaccharide)?

A

Glucose + Fructose

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71
Q

What monosaccharides make up Lactose?

A

Glucose + Galactose

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72
Q

What monosaccharides make up Maltose?

A

Glucose + Glucose

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73
Q

What is Starch?

A

Polymers of glucose used for energy storage in plants

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74
Q

What is Glycogen?

A

Polymers of glucose used for energy storage in animals

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75
Q

What are Chargaff’s Rules for DNA and RNA?

A

DNA: A-T & C-G
RNA: A-U & C-G

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76
Q

Which nitrogenous bases are Purines?

A

Adenine and Guanine

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77
Q

Which nitrogenous bases are Pyrimidines?

A

Cytosine, Thymine, and Uracil

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78
Q
A

Adenine

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79
Q
A

Guanine

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80
Q
A

Cytosine

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81
Q
A

Thymine

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82
Q
A

Uracil

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83
Q

What is significant about the nucleus in Eukaryotic cell structure?

A

Contains DNA and nucleolus; Site of DNA replication and Transcription

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84
Q

What is significant about the genetic information in Mitochondria?

A

Mitochondria contain circular mtDNA that is self-replicating

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85
Q

Cytoskeleton

A

Made up of microfilaments, microtubules, and intermediate filaments; Helps maintain structure of the cell and carry out basic functions

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86
Q

Plasma Membrane

A

Composed of phospholipid bilayer with lipid rafts and transmembrane proteins; regulates signaling and transport

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87
Q

Describe the phases of the Cell Cycle

A

Resting Phase: Cell carries out normal activities
Interphase: Preparation for division, DNA synthesized and G1/S and G2 checkpoints make sure that cell is ready for division
Mitosis: Cell Division

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88
Q

Describe the phases of Mitosis

A

Prophase: Nuclear membrane disappears, chromosomes condense, mitotic spindle forms
Metaphase: Chromosomes line up along metaphase plate
Anaphase: Chromosomes pulled apart
Telophase/Cytokinesis: Nuclear envelope and nucleolus reappear, cells divide

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89
Q

Describe the significantly different phases in Meiosis (as compared to mitosis)

A

Meiosis I: Two haploid daughter cells with duplicate sister chromatids
Prophase I: Homologous chromosomes pair up in synapsis, exchange genetic information in crossing over (meiosis + crossing over is a major source of genetic variability in sexual reproduction)

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90
Q

Bacteria

A

No membrane-bound organelles, no nucleus, circular genome

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91
Q

Describe the various bacteria shapes

A

Cocci = spheres
Bacilli = rods
spirilla = spirals

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92
Q

Obligate Aerobes

A

Require oxygen for metabolism

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93
Q

Obligate Anaerobes

A

Require oxygen-free environments for metabolism

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94
Q

Facultative Anaerobes

A

Can perform metabolism with or without oxygen

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95
Q

What do bacterial cell walls contain?

A

Peptidoglycan

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96
Q

Describe the difference between Gram-Positive and Gram-Negative bacteria

A

Gram-Pos: turn purple in gram staining; have thick peptidoglycan cell walls
Gram-Neg: Turn pink in Gram staining, have thin wall with outer lipopolysaccharide layer

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97
Q

Describe ribosomes in prokaryotes and eukaryotes

A

Prokaryotic Ribosomes (70S) are structurally different than eukaryotic ribosomes (80s)

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98
Q

Transformation

A

DNA from environment is absorbed

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99
Q

Transduction

A

Virus-mediated gene transfer

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100
Q

Conjugation

A

Like sexual reproduction for bacteria

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101
Q

Describe Viruses

A

Obligate intracellular parasites (need cell to multiply), protein capsid coat around genetic material

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102
Q

Lytic Cycle

A

Cellular machinery hijacked, host cell killed, explodes, releases viruses

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103
Q

Lysogenic Cycle

A

Virus incorporates itself into host genome and waits. Only in bacteriophages

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104
Q

What does the central dogma state?

A

Information flows from DNA to RNA to protein

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105
Q

What is a Codon?

A

Group of 3 RNA bases that code for amino acids; third position is “wobble”

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106
Q

What are the stop codons?

A

UAA, UAG, UGA (You are annoying, you are gross, you go away)

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107
Q

What is the start codon?

A

AUG (methionine)

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108
Q

What are the complementary base pairs?

A

A/T (U in RNA) & C/G

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109
Q

Describe the orientation of strands in DNA

A

Antiparallel

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110
Q

Describe the two different states DNA can be in as it is coiled around histones.

A

Euchromatin: Loose and transcriptionally active
Heterochromatin: Dense and transcriptionally inactive

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111
Q

What method describes DNA replication?

A

Semiconservative

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112
Q

Describe the actions of DNA polymerase (what direction does it read)

A

DNA polymerase reads 3’-5’ and synthesizes 5’-3’

113
Q

Describe replication fluidity on leading and lagging strand

A

Replication is uninterrupted on leading strand; Interrupted on lagging strand - results in Okazaki fragments that are joined together using ligase

114
Q

Describe the difference between the sense and anti-sense strands

A

In transcription, mRNA is synthesized from the antisense (template) strand; mRNA is therefore identical (except for U substituted for T) to the sense strand

115
Q

Describe post transcriptional modifications

A

hnRNA is formed initially, undergoes 3’ poly-A tail addition (anti-degredation in cytoplasm), 5’ cap addition (transport and anti-degredation), and splicing (non-coding sequences (introns) removed and coding sequences (exons) ligated together) …. This all forms mRNA

116
Q

Describe the general process of Translation

A

mRNA –> Protein; Occurs in ribosomes by tRNA (which is “charged” with amino acid residues”); tRNA builds proteins in ribosomes

117
Q

Describe the difference between prokaryotic and eukaryotic ribosomes

A

Prokaryotic: 70s (30s + 50s)
Eukaryotic: 80s (40s + 60s)

118
Q

Describe the steps of Translation (3); What are the binding sites for elongation?

A

Initiation, elongation, termination (binding sites for elongation are A, P, E)

119
Q

Silent Mutations

A

Do not affect amino acids outcome (due to wobble)

120
Q

Point mutations (missense mutations)

A

Conservative: Similar Amino Acids
Non-Conservative: Amino acids with different properties

121
Q

Nonsense mutations

A

Premature stop codon

122
Q

Insertions/Deletions

A

Frameshift mutations, change all downstream amino acids

123
Q

Translocations

A

Larger-scale mutation: Swap of genetic material

124
Q

Aneuploidy

A

Larger scale mutation: occurs due to nondisjunction during division

125
Q

What is an Allele?

A

Specific variant of a given gene, such as round/wrinkled shape of peas

126
Q

What is a test-cross?

A

Dominant-phenotype individual crossed with recessive individual to determine phenotype

127
Q

Codominance

A

Two different alleles expressed at the same time (Example: Spotted Cow)

128
Q

Incomplete Dominance

A

Blended phenotype in heterozygotes (red + white flower results in a pink flower)

129
Q

What does the law of independent assortment state?

A

Inheritance of various genes not correlated with each other

130
Q

Define Linkage

A

Exception to independent assortment; Genes physically close together on the same chromosome tend to have their alleles inherited together (Recombination frequency can be used to map location of genes on chromosomes)

131
Q

Autosomal Inheritance vs. Sex-Linked Inheritance

A

Autosomal: Genes on non-sex chromosomes
Sex-linked: Genes on X chromosome

131
Q

How do we characterize recessive inheritance versus dominant inheritance in a family tree?

A

Recessive inheritance skips a generation, while dominant inheritance usually does not

132
Q

Describe how we determine if a gene is sex-linked by looking at a family tree

A

X-linked recessive traits affect more males than females because males only have one X chromosome; Therefore, inheritance of sex-linked traits is usually gender dependent

133
Q

What are the 6 assumptions of the Hardy-Weinburg Equilibrium?

A

(1) Diploid sexual reproduction
(2) Random Mating
(3) Large population
(4) Random distribution of alleles by sex
(5) No mutations
(6) No migration

134
Q

What is the equation for Hardy-Weinburg Equilibrium?

A
135
Q

Define Fitness

A

Fitness is defined in terms of reproductive success

136
Q

Define Speciation. What is it defined by?

A

Formation of a new species, defined by reproductive isolation (inability to produce fertile offspring with another species)

137
Q

Stabilizing Selection

A

Extremes selected against, phenotype maintained within strict region

138
Q

Directional Selection

A

One extreme selected against, phenotype moves to one end

139
Q

Disruptive Selection

A

Middle selected against, population swings to favor both extremes

140
Q

Describe the “molecular clock” method of dating divergence from last common ancestor.

A

Accumulation of random changes in genome over time is constant, therefore number of changes can help determine time

141
Q

Define Gene Expression

A

Explains how cells with same DNA become different in development

142
Q

Stem Cells

A

Stem cells are capable of differentiation, to varying extents

143
Q

Totipotent Stem Cells

A

Can differentiate into any type of cell

144
Q

Pluripotent Stem Cells

A

Can differentiate into any of the 3 germ layers

145
Q

Multipotent Stem Cells

A

Have a more limited range of differentiation

146
Q

What kind of cells have Operons?

A

Prokaryotic cells

147
Q

Describe Positive vs. Negative Control in Operons

A

In negative control, a repressor prevents transcription
In positive control, an activator stimulates transcription

148
Q

Describe the Lac Operon

A

Negative inducible; In absence of lactose, repressor blocks transcription. When lactose is present, allolactase disengages repressor, allowing transcription; Low Glucose levels upregulate transcription through CAP (positive control)

149
Q

Describe the Trp Operon

A

Negative Repressible; Tryptophan is usually synthesized, but when already present, tryptophan causes repressor to bind to operator sequence and block transcription

150
Q

Promoters (gene expression in Eukaryoties … Prokaryotes use operons)

A

Upstream DNA sequences that initiate transcription

151
Q

Enhancers

A

DNA sequences that allow increased transcription

152
Q

Transcription Factors

A

Proteins that regulate expression by binding to a specific DNA sequence

153
Q

Heterochromatin

A

Dense, associated with transcriptional inactivity

154
Q

Euchromatin

A

Loose, associated with transcriptional activity

155
Q

Histone Acetylation

A

Increases transcription (loosens binding around histones)

156
Q

DNA Methylation

A

Decreases transcription

157
Q

siRNA and miRNA

A

Non-coding RNA that inhibits protein synthesis by blocking other RNA molecules

158
Q

Cancer

A

Associated with mutations and altered gene expression patterns leading to uncontrolled proliferation of cells

159
Q

Oncogenes

A

When oncogenes are turned on via mutations, they promote cell division and thus cancer

160
Q

Tumor Suppressor Genes

A

Normally restrict cell division, when inactivated, cancer is more likely to develop

161
Q

Restriction Enzymes

A

“Restriction Endonucleases”
Cut DNA at specific points, leading to blunt and sticky ends that can be recombined

162
Q

How are plasmids and bacteriophage vectors related to Recombinant DNA?

A

Plasmid and bactoriophage vectors are used to transfer/amplify recombinant DNA

163
Q

Electrophoresis

A

Laboratory technique that separates DNA & RNA molecules by size; Pulls molecules through agarose gel based on charge.

164
Q

Hybridization (laboratory technique)

A

Refers to the ability of single strand DNA (or RNA) to jion with complementary base pair sequences; Used in southern, northern, and western blotting to detect specific DNA, RNA< and protein sequences, respectively

165
Q

Polymerase Chain Reaction (PCR)

A

Laboratory technique used to make exponentially large numbers of copies of DNA in a short amount of time; Uses primers

165
Q

Sanger Sequencing

A

Initial method for sequencing DNA; USes dideoxynucleotides to terminate DNA synthesis, then uses electrophoresis to analyze size of each fragment; This analysis can be used to piece strands of DNA together

166
Q

Nervous System

A

The nervous system serves to take in and integrate information from the environment and allows the organism to respond appropriately

167
Q

Central Nervous System

A

The central nervous system includes both the brain and the spinal cord. The various components of the brain are associated with key functions

168
Q

Peripheral Nervous System

A

The peripheral nervous system is divided into the autonomic and somatic nervous systems.

169
Q

Somatic Nervous System

A

The somatic nervous system controls voluntary responses via skeletal muscle

170
Q

Autonomic Nervous System

A

The autonomic nervous system controls involuntary responses through the sympathetic (fight or flight) and the parasympathetic (rest and digest) systems

171
Q

Neurons and Glial Cells

A

The functional unit of the nervous system is the neuron, and all neurons require supporting glial cells to function correctly

Glial Cells include oligodendrocytes, Schwann Cells, ependymal cells, satellite cells, astrocytes, and microglia

172
Q

Types of Neurons

A

Neurons come in several types, including sensory cells that are bipolar and pseudounipolar, and motar and interneurons that are multipolar

173
Q

Resting Potential

A

Neurons maintain a resting potential of -70mV by pumping sodium out and potassium into the cell. They maintain selective permeability that does not allow sodium ions or proteins bearing negatively charged resides to pass through the membrane

174
Q

Neurons Transmit Information via Action Potentials. Describe this process.

A
  • An action potential begins with a depolarization phase during which sodium rushes into the cell
  • After peaking at +40 mV, the cell closes sodium channels and opens potassium channels. Potassium rushes out of the cell, repolarizing it
  • The cell briefly hyper-polarizes with a potential below -70 mV. During this phase, it is much more difficult to stimulate a new action potential.
  • The sodium-potassium pump re-establishes the resting state
175
Q

What happens when the action potential reaches the end of the axon?

A

When the action potential reaches the end of the axon, the signal is transmitted to the post-synaptic membrane via a neurotransmitter

Calcium rushes in to the pre-synaptic axon terminal, which sends vesicles containing neurotransmitter into the synaptic cleft. The neurotransmitter binds to the post-synaptic membrane and serves as a catalyst for its effect

176
Q

How are physics and physiology related (action potentials)

A

Neurons can be modeled both as concentration cells and as capacitors. The MCAT will want you to be familiar with these concepts from chemistry and physics and be able to apply them even if you are working through a biology passage.

177
Q

Endocrine System

A
  • Refers specifically to ductless glands that release signaling molecules (hormones) into the circulation
  • Its role is communication among organ systems
  • Endocrine signaling is slower than neural signaling
  • Many endocrine functions are ultimately controlled by the nervous system (through intermediaries)
178
Q

Structural Differences between peptide hormones, steroid hormones, and amino acid hormones, and how they contribute to the function of these hormone types

A
  • Peptide hormones are made up from amino acid chains and are hydrophilic. Steorid hormones are derived from cholesteroal, have a four-ring structure, and are lipophilic
  • Peptide hormones cannot diffuse through the plasma membranes of their target cells, so they interact with transmembrane receptors that activate second messenger signaling systems in the cytosol
  • Steroid hormones can and do diffuse through the plasma membranes of their target cells, bind with receptors, and influence gene expression in their target cells
  • Peptide hormones typically have quick-onset, short-acting effects. Steroid hormones typically have a delayed onset and long lasting effects
179
Q

Steroid Hormones

A

Stoeroid hormones affect sex (estrogen, testosterone, progesterone), salt (aldosterone, a mineralocorticoid), and sugar (cortisal, a glucocorticoid).

180
Q

Amino Acid Derived Hormones

A

Amino-acid derived hormones include T3/T4 and (nor)epinephrine. All other high-yield hormones are peptides

181
Q

Negative Feedback

A

Common in the body; Downstream product inhibits upstream steps; Maintains homeostasis

182
Q

Positive Feedback

A

Unusual in body; Downstream product upregulates upstream steps; pushes the body towards an extreme state; an example of this is oxytocin in labor/childbirth

183
Q

Glucose (endocrine system)

A

Insulin decreases glucose, glucagon increases glucose

184
Q

Serum Calcium Concentration (endocrine system)

A

PTH and calcitrol (active form of vitamin D) increase Ca2+, calcitonin decreases Ca2+

185
Q

Fluids regulation (endocrine system)

A

Aldosterone and ADH increase fluid retention, ANP increases fluid excretion

186
Q

Stress regulation (endocrine system)

A

Cortisol: increases glucose, long-term stress
Epinephrine: increases glucose and fight or flight response, short-term stress

187
Q

Metabolic Rate regulations (endocrine system)

A

T3 and T4 increase basal metabolic rate

188
Q

Reproduction and development regulations (endocrine system)

A

Estrogen and testosterone initiate and maintain secondary sex characteristics

189
Q

Tropic Hormons

A

Play a role in multi-step signaling pathways

190
Q

Path of a sperm through the male reporductive tract

A

seminiferous tubules –> epididymis –> vas deferens –> ejaculatory duct –> urethra –> penis

SEVEn UP (where “n” stands for nothing)

191
Q

Path of Eggs through female reproductive tract

A

Ovaries –> Fallopian Tube, then:

If fertilization occurs –> Zygote/morula/blastocyst goes to uterus –> pregnancy –> childbirth through vaginal canal

In no fertilization occurs: Uterine lining shed during mensturation

192
Q

Spermatogenesis

A
  • Takes place in testes, which are maintained a few degress Celsius cooler than body temperature.
  • Spermatogonial stem cells –> spermatogonia (2n) –> primary spermatocytes (2n) –> secondary spermatocytes (n) –> spermatids –> spermatozoa
193
Q

Epididymis

A

Sperm mature and gain motility in epididymis

194
Q

Spermatogenesis

A

A constant process from puberty throughout rest of lifespan

195
Q

Oogenesis

A

Oogonia –> primary oocyte –> secondary oocyte + polar body –> ovum + polar body

196
Q

Is oogenesis a constant process?

A

No, oogenesis is not a constant process. Primary oocytes are halted at prophase I at birth, meiosis I completed in the ovary to form secondary oocyte, which is then arrested at metaphase II. Meiosis II is completed at fertilization.

197
Q

Fertilization

A

Takes place in fallopian tube; Acrosome reaction allows sperm cell to enter egg. Results in cortical reaction that prevents polyspermy.

198
Q

Stages of Emrbyonic Development

A
  1. Morula (16-cell ball) –> Blastocyst (fluid-filled sac in the middle) –> gastrula (three germ cell layers present).
  2. Ectoderm –> Skin, nervous system, sweat glands, hair, nails
  3. Mesoderm –> connective tissue (including blood and bone), muscles, gonads
  4. Endoderm –> internal linings of GI tract, lungs, urinary bladder
199
Q

Menstrual Cycle

A

Takes place every ~28 days in reproductive age women

200
Q

Ovarian Cycle

A

Follicular phase (follicle develops), ovulation (egg is released), luteal phase (follicle –> corpus leuteum)

201
Q

Uterine Cycle

A

Menstruation (uterine endometrium from previous cycle is shed), proliferative phase (endometrium develops again), secretory phase (endometrium is ready for implantation)

202
Q

Hormones in Menstration Cycle

A

Estrogen gradually rises throughout follicular phase, triggering LH surge, which causes ovulation. Progesterone, secreted by corpus luteum, maintains uterine endometrium for implantation

If implantation happens, human chorionic gonadotropin (hCG) maintains corpus leuteum, thereby maintaining progesterone and maintaining pregnancy

203
Q

Respiratory Anatomy

A

Nasal/oral cavity –> pharynx –> trachea –> bronchi –> bronchioles –> alveoli

Pleura surround lungs in the thoracic cavity. Surfactant covers alveoli to decrease surface tension and prevent them from collapsing.

204
Q

Inspiration

A

Diaphragm contracts, expanding lungs; greater volume = lower pressure, air comes in from outside

205
Q

Ciliated Cells and Mucus in respiratory tract

A

Ciliated cells and mucus in trachea and bronchi help trap particulate matter and push it up to be either expelled or swallowed

206
Q

Basic point of respiration

A

Carbon dioxide produced as waste product of metabolism needs to be exhaled, and oxygen for aerobic respiration needs to be inhaled

207
Q

Connection between CO2 and pH due to bicarbonate equilibrium

A
208
Q

Blood Contents

A

Blood contains plasma (non-cellular component), platelets (thrombocytes), white blood cells (leukocytes) and red blood cells (erythrocytes)

209
Q

Erythrocytes

A

Red blood cells; lack nuclei and membrane-bound organelles; rely on anaerobic metabolism, have biconcave shape, and are packed with hemoglobin (which carries oxygen and some carbon dioxide)

210
Q

Basic Cardiovascular Anatomy

A

Venae Cave –> right atrium –> tricuspid valve –> right ventricle –> pulmonary semilunar valve –> pulmonary trunk and arteries –> capillaries (gas exchange) –> pulmonary veins –> left atrium –> bicuspid (mitral) valve –> left ventricle –> aortic semilunar valve –> aorta –> systemic circulation

211
Q

Arteries vs. Veins

A

Arteries take blood away from the heart, while veins take blood back to the heart

212
Q

Blood Vessels

A

Aorta > arteries > arterioles > capillaries > venules > veins > venae cavae

213
Q

Pressure and Velocity in Circulatory System

A

Pressure decreases as blood moves through the circulatory system, and velocity decreases from arteries to capillary beds

214
Q

Hemoglobin

A

A protein composed of four units, each with a heme group that contains an iron which binds oxygen

215
Q

Hemoglobin-Oxygen Binding

A

Cooperative; Hemoglobin has T form, which is resistant to binding, and R form, which facilitates easier binding. The first bound oxygen stabilizes the R form.

216
Q

Hemoglobin Dissociation Curve Shifts

A

Rightward shift of oxygen-hemoglobin dissociation curve means a lower affinity. Caused by increased CO2, increased H+, decreased pH (Bohr effect), increased 2,3-BPG, and increased temperature. Leftward shift means higher affinity. Caused by opposite of above conditions and in fetal hemoglobin.

217
Q

Importance of Hemoglobin’s Biochemical properties

A

Biochemical properties of hemoglobin allow it to pick up oxygen in the lungs and deliver it to where it is needed in tissues undergoing active metabolism

218
Q

Basic Path of Food through the digestive system

A

Oral Cavity –> Esophagus –> stomach –> small intestine (duodenum, jejunum, ileum) –> Large intestine (cecum, ascending colon, transverse colon, descending colon, sigmoid colon) –> Rectum

219
Q

pH of Digestive System

A

Stomach has a very low pH due to gastric acid. pH becomes slightly alkaline in small intestine

220
Q

Bile

A

Generate in liver, stored and concentrated in gallbladder, released to small intestine to emulsify fats

221
Q

Pancreas

A

Secretes digestive enzymes and bicarbonate and releases them to small intestines

222
Q

Small Intestine

A

Main site for digestion and absorption of nutrients; Villi multiply surface area of small intestinal lining; Microvilli on surface of cell increase surface area available for absorption

223
Q

Large Intestine

A

Re-Absorption of H2O, large microbial comunity, absorption of microbe-generated substances (Vitamin K, short chain fatty acids)

224
Q

Carbohydrates

A

Salivary amylase in mouth –> digestive enzymes (pancreatic amylase + disaccharidases) in small intestine –> Monosaccharides absorbed into small intestine cells –> Hepatic portal vein for liver processing –> bloodstream

225
Q

Proteins

A

Pepsin in stomach –> Various peptidases in small intestines; isolated amino acids primarily absorbed in small intestine, as well as some dipeptides –> absorbed into small intestinal cells –> lacteals in villi –> drain into lymphatic system as chylomicrons –> bloodstream

226
Q

Vitamins

A

Fat Soluble = A, D, E, K
Water Soluble = B and C

227
Q

Function of Vitamins

A

Vitamins have a range of functions. Notably A helps in vision, D in calcium/phosphate regulation, K in clotting, C in collagen synthesis, and B vitamins are many important coenzymes/factors

228
Q

Basic Urination Path

A

Glomerulus (blood vessels) –> capsular space of Bowman’s capsule –> proximal convoluted tubule –> Loop of Henle (descending limb and ascending limb), distal convoluted tubule –> collecting duct

Collecting duct –> minor calyx –> major calyx –> renal pelvis –> ureters –> urinary bladder –> urethra

229
Q

Two Major Functions of the Nephron

A

(1) Filtering various substances in the blood
(2) Appropriately regulating fluid/salt content of urine

230
Q

Loop of Henle

A

Loop of Henle has countercurrent multiplier mechanism to greatly reduce liquid volume in urine by first making urine concentrated (descending limp) then removing solutes (ascending limb)

231
Q

Aldosterone

A

increased Na+ reabsorption = increased H2O reabsorption (especially in the presence of ADH) = increased plasma volume of blood = increased blood pressure

232
Q

ADH

A

increased H2O retention = increased plasma volume of the blood = increased blood pressure

233
Q

ANP

A

Decreased Na+ reabsorption = decreased H2O reabsorption = decreased plasma volume of blood = decreased blood pressure

234
Q

Urinary System

A

Regulates blood pressure and blood volume, blood osmolarity and ion levels, pH, excretion of nitrogenous wastes and foreign substances

235
Q

Antigen

A

Any substance that stimulates an immune response

236
Q

Anitbody

A

Y-shaped molecule that recognizes antigens and allows an immune response to be mobilized. Has two heavy and two light chains linked by disulfide bonds

237
Q

Anitgen-Antibody interactions

A

Lock lock in a key, antibodies are specific for specific antigens

238
Q

Self/non-Self

A

Mediated by major histocompatibility complex (MHC) class I and II

239
Q

MHC

A

Unique to every person

240
Q

MHC Class I

A

Expressed in all nucleated cells, shows fragments of proteins from inside cell. Can be thought of as internal quality check. Abnormal in cases of viral infections or tumorigenesis. CD8+ T cells destroy.

241
Q

MHC Class II

A

Expressed in some immune cells (macrophages, etc.), shows fragments of antigens from external invaders that have been engulfed; CD4+ helper T cells recruit response

242
Q

Anatomical Barriers (innate immune system)

A

Skin, digestive enzymes, lysozymes in saliva/tears/breastmilk, mucociliary elevator in respiratory tract

243
Q

White blood cells (innate immune system)

A

Neutrophils (phagocytose bacteria), NK cells, monocytes (differentiate into macrophages (“big eaters”) and dendritic cells), Eosinophils, and basophils

244
Q

Complement (innate immune system)

A

Proteins involved in signaling cascade to tag pathogens, recruit phagocytes, and initiate inflammatory process

245
Q

Cytokines (innate immune system)

A

Signaling proteins that coordinate immune response/inflammation. Interferons are cytokines that specialize in response to viruses

246
Q

B cells (adaptive immune system)

A

Differentiate into plasma cells for antibody production. Produced in bone marrow and are activated in lymphatic organs or tissues. When activated, clonal expansion –> many copies

Short-lived plasma cells produce antibodies in response to current infection, memory cells remain present and react next time a threat appears

247
Q

T-Cells (adaptive immune system)

A

Mature in thymus through positive/negative selection. Most are discarded.

248
Q

CD4+ Helper T Cells (adaptive immune system)

A

Coordinate response to abnormal MHC class II (bacterial/fungal/other infection)

249
Q

CD8+ Cytotoxic T Cells (adaptive immune system)

A

Kills cells with abnormal MHC class I (virus/tumor)

250
Q

Other T Cells (adaptive immune system)

A

Suppressor T cells (also called regulatory T cells) moderate immune reaction when response has been sufficient.

Memory T cells “remember” previous antigens

251
Q

Anatomy of Immune System

A

Bone marrow, lymphatic system, spleen, thymus, and other lymphatic tissues (appendix, tonsils, etc.)

252
Q

Lymphatic System

A

Regulates fluid balance, is home for lymphocytes (B and T cells), drains fats from digestive system into bloodstream, returns substances from interstitial space to circulation

253
Q

Connective Tissue

A

Includes bone, blood, adipose tissue as well as cartilage, ligaments, tendons (as well as a few other types)

254
Q

Cartilage

A

Avascular, connective tissue

255
Q

Ligaments

A

Tough tissue connecting bones to bones

256
Q

Tendons

A

Tough tissue connecting muscles and bones

257
Q

Bone Types

A

Long (ex. humerus, femur), flat (ex. skull), short (ex. wrist/ankle bones), sesamoid (ex. patella), irregular (ex. ethmoid)

258
Q

Synovial Joints

A

Bones connected by lubricated synovial cavity (elbow)

259
Q

Cartilaginous Joints

A

Bones connected by cartilage (vertebral discs)

260
Q

Fibrous Joints

A

Bones connected by fibrous connective tissue (skull bones)

261
Q

Joint Mobility Classifications

A

Diathrosis (freely movable), amphiarthrosis (slightly movable), synarthrosis (immovable)

262
Q

Bone Matrix

A

Minerals (hydroxyapatite), collagen, water. Calcium/phosphate resevoir

263
Q

Osteoblasts

A

Build up bone

264
Q

Osteoclasts

A

Break down bone

265
Q

PTH

A

increased Ca2+ from bone

266
Q

Vitamin D

A

Increased Ca2+ from intestine

267
Q

Calcitonin

A

Decreased Ca2+ in blood by inhibiting osteoclast activity

268
Q

Bone Marrow

A

Hematopoiesis

269
Q

Skeletal Muscle

A

Voluntary (somatic nervous system), striated, multinucleated. Red (slow-twitch) fibers contain abundant myoglobin, specialize in long-lasting actions requiring oxidative metabolism

White (fast-twitch) fibers contain less myoglobin and specialize in short bursts of action primarily using glycolysis

270
Q

Smooth Muscle

A

Involuntary (autonomic nervous system), non-striated, uninucleate. Can undergo myogenic activity (contraction in absence of nervous stimulation)

271
Q

Cardiac Muscle

A

Involuntary (autonomic nervous system), striated. Usually uninucleated. Sinoatrial node sets pace of contractions that can be modified by other signaling. Intercalated discs/gap junctions allow signals to spread

272
Q

Muscle Contraction

A

Sliding actin/myosin filaments. ATP required to dissociate actin and myosin. ATP –> ADP to “cock” myosin head; Ca2+ binds to troponin which moves tropomyosin to allow actin and myosin to bind. Pi is released to generate power stroke

273
Q

Sarcomere

A

I-band (thin filaments only), H-zone (thick filaments only), distances between M-lines (center of H-zone) and Z-lines (center of I-band) contract; A-band (entire area where thick filaments are present) stays the same during contraction

274
Q

Layers of the Skin

A

From most superficial to deepest
Epidermins > dermis > hypodermis (although not technically part of the skin)

275
Q

Epidermis

A

Contains layers of dead keratinocytes that provide physical protection, as well as melonocytes (pigment) and merkel cells (touch)

276
Q

Dermis

A

Capillaries, lymph vessels, hair follicles, sweat glands, sensory cells

277
Q

Skin heat regulation

A

Thermoregulation via sweating, vasoldilation/vasocontriction, piloerection

MCAT (6 decks)

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