Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT > 4 > Flashcards

4 Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards
1
Q

Hindsight bias

A

In retrospect, events seem more predictable and obvious
- Very common in medicine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Causation bias

A

Thinking that events closely related in time share a causal link

  • post hoc ergo propter hoc
    • after this, therefore because of this fallacy

Mistake correlation for causation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Heurisitics

A

Mental shortcuts and problem solving methods

  • fixed, rigid processes to arrive at a quick answer, even from incomplete information

Examples of heuristics refer to ways that we assess probability of certain outcomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Biases

A

General cognitive patterns that affect our decision making processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Representative heuristic

A

Making decisions based on prototypical examples

  • usually when estimating probability in everday life
  • ex. looking like a criminal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Availability heuristic

A

How likely we think something is to occur

Influenced by readily available info

ex. Rare crime news stories, thinking they could happen to us

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Second year syndrome

A

Learning about rare syndromes and thinking any symptom could be caused by it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Intelligence

A

Ability to:

  • Detect patterns
  • Process and store info
  • Understand ideas
  • Solve problems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Charles Spearman

A

Noticed correlation in performance in different subjects

  • children who did well in history did well in math
  • not a perfect correlation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

General intelligence (g factor)

A

Underlying capacity that drives performance in may fields

  • about 50% heritable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Francis Galton

A

Inspired by work of Charles Darwin, laid foundation for eugenics which embraced selective breeding

  • endorsed racist ideas
  • provided framework for unethical practices
  • wrong turn in biology and anthropolgy

However wrote book about hereditary genius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Alfred Binet

A

The IQ scale, estimation of a child’s mental age relative to their chronological age

  • mental age/chronological age x 100

Doesn’t apply well for adults

In adults, IQ is an estimate of geneal intelligence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

IQ distribution

A

Normal distribution, few people have extreme low or high

68% within 1 SD of mean

95% of pop within 2 SD of mean

SD is +/- 15 points

Mean is 100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

IQ controversy

A

IQ tests are high stakes

Can influence education a child receives

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Flynn effect

A

flynn effect: describes how IQ scores increased in developed countries in 20th century

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Howard gardner multiple intelligences

A

Make up g-factor

  1. Musical
  2. Visual-spatial
  3. Verbal-linguistic
  4. Logical-mathematical
  5. Bodily-kinesthetic
  6. Interpersonal
  7. Intrapersonal

*8. Naturalistic- relate to/pick up patterns in natural world

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Emotional intelligence

A

Recognition of one’s own emotions and those of others

  • emotional self regulation
  • proposed it was an equal counterpart to traditional intelligence
    • EQ
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Language

A

Structure and underlying similarities of all human languages

  • cognitive aspects of learning and using linguistic systems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Phonetics

A

Study of physical production and reception of speech sound

  • anatomical parts of speech and hearing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Phonology

A

Organization of sounds into meaningful units

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Morphology

A

Study of word formation

ex. eat –> ate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Syntax

A

How words are joined together to form phrases/sentences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Semantics

A

Literal meaning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Pragmatics

A

Non-literal meaning

  • depends on context, body language, time
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

American sign language has its own

A

Grammar and words

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Behaviorism

A

B.F. Skinner

observable behavior

Learning theory of language

Nativist theory

Generative linguistics

Interactionist Theory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Learning Theory of Language

A

Language as behavior based on environmental input

  • no innate language capacity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Nativist Theory

A

Noam Chomsky

Humans have innate (genetic) capacity for language

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Generative linguistics:

A

grammatical rules which govern sentences, certain sentence structures don’t work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Interactionist Theory

A

Language is acquired during social interaction

  • language leaning is interactive and functional
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Benjamin Whorf

Sapir-Whorf

A

Studied Hopi language

No past/future tenses, no sense of time passing continuously

Sapir-Whorf (linguistic relativity): grammatical categories and vocabulary influence thought

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Linguistic determination

A

Grammatical categories determine thought

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Aphasia

Wernicke’s aphasia

Broca’s aphasia

A

An impaired ability to communicate

Wernicke’s aphasia: impaired language comprehension aka fluent aphasia

Broca’s aphasia: understand language but impaired speech production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Arcuate fasciculus

A

Connects broca’s and wernickes areas

conductive aphasia: arcuate fasciculus lesions cause difficulties with repeating other peoples words

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

RNA world hypothesis

A

RNA stored info and catalyzed reactions before DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Transcription

A

Similar to replication

  • Copying DNA into complementary strand, both occur in nucleus
  • Don’t have to worry about lagging or leading strands or replicating ends of chromosomes
  1. Douple helix unzipped by helicase, kept open by single stranded binding proteins (SSBP)

2. Tension created upstream relieved by topoisomerase enzyme

  1. RNA pol catalyzes transcription; locates specific sequences for genes its interested in
  • upstream promoter TATA box, A-T rich sequence recognized by RNA pol
  • bonds with the help of transcription factors

** Reads DNA template 3’ to 5’, makes mRNA 3 to 5

  1. Reaches transcription terminator sequence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

RNA pol proofreading ability is

A

Not as accurate as DNA polymerase

Error rate higher, not as high of a risk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Template (antisense) strand

A

Strand being read by RNA pol in transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Coding (sense) strand

A

Sequence identical to new RNA with thymine instead of Uracil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

RNA pol I

RNA pol II

RNA pol III

A

Synthesizes rRNA in nucleolus

Synthesizes hnRNA (heteronuclear)(mRNA precursor)

SYnthesizes tRNA, some rRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Prokaryotic transcription and translation occur…

A

In prokaryotes, new RNA is immediately ready to be translated

  • Transcription and translation occur simultaneously on same RNA molecule

Prokaryotic RNA is polycistronic, can code for multiple proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

heteronuclear hnRNA posttranscriptional modification

polyA tail

5’ cap

splicing

A

pre mRNA that undergoes posttranscriptional modification

  1. RNA gains polyA tail at 3’ end: facilitates binding to nuclear export proteins, assist with mRNA translocation through pores in nuclear membrane
  • main purpose is to protect mRNA from degradation in cytosol when going from nucleus to cytosolic ribosomes
    • degradation by 3’ exonucleases
  • more adenine residues = better defense
  1. 5’ cap: one nucleotide modification, triphosphate linkage
  • protects mRNA against degradation, facilitates nuclear export (recognized by tranport proteins)
  • also recognition for ribosomes
  1. RNA splicing- splicing introns
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

pre mRNA splicing

Enzyme?

A

introns: intervening sequences of noncoding, spliced

exons: expressed sequences which are ligated back together

Catalyzed by splicosome made up of proteins and snRNA which combine to form snRNP (small nuclear ribonuclear proteins)

  • snRNPs recognize marker sequences at end of introns, pulling them together to form lariat loop

One mRNA precursor can be spliced to code for different proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Ribozymes

A

RNA components capable of enzymatic activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Translation - protein from RNA

secreted vs. cytoplasmic proteins

Ribozyme?

A

RNA nucleotides arranged in triplet codons and code for aminos

secreted proteins: membrane bound ribosomes on rough ER, fed into ER then directed to golgi apparatus -> secretory vesicles

cytoplasmic proteins: come from free ribosomes in cytoplasm

Ribosomal rRNA: ribozymal component of ribosomes, catalyzes formation of peptide bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Degeneracy

A

Multiple codons can correspond to one amino acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

tRNA:

A

clover leaf hairpin secondary structure, recognize triplet codons on mRNA and attach corresponding amino acids to growing chain

each tRNA has unique anticodon complementary to mRNA codon

tRNA becomes “charged” when bound to corresponding amino

  • to charge tRNA with correct amino
    • amino acyl-tRNA synthetase links C-terminus of aminos to 3’ end of tRNA
      • requires ATP, which energy is later harnessed to create peptide bond
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

wobble hypothesis:

A

1 tRNA can recognize several codons, usually where 3rd amino differs – creates same amino

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Synthesizing protein is

A

Expensive to cell in terms of ATP (charging tRNAs)

  • *One reason gene expression is tightly regulated, so ATP isn’t wasted
  • Makes only necessary proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Steps of Translation - Initiation

A
  1. Small ribosomal subunits recognize and binds specific mRNA sequence
  • in prokaryotes, location is the Shine-Dalgarno sequence in 5’ untranslated region upstream of start
  • In eukaryotes, recognize 5’ cap and intiator tRNA binds to start codon AUG
    • ​tRNA is always charged with methionine first

2. initiation factors facilitate binding of large subunit to small, forming initiation complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Steps of Translation - Elongation

A
  1. Ribosome with elongation factors read mRNA 5’ to 3’
  • one triplet codon at a time
  • Ribosome synthesizes polypeptide from N-terminus to C-terminus
    • N-C polarity of all aminos
  1. Ribosome assemply has 3 binding site for tRNA: A acceptor site, P peptidyl site (forms peptide bond), E exit site, uncharged tRNA leaves
    * tRNAs move over exposing A site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Steps of Translation - Termination

A

Occurs when ribosome encounters 1 of 3 stop codons: UAA, UAG, UGA

Don’t code for an amino, instead recognized by release factors at P site

Ribosome evicts protein and moves onto next mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Where does postranslational modification occur?

Types?

A

Mostly in rough ER and golgi apparatus

  • addition of carbohydrates and some protein cleavage
  • proteins can be covalently linked to variety of functional groups
    • ex.
      • phosphorylation: adding high energy phosphate group by kinase enzymes

Glycolysation: addition of carbohydration moieties, often catalyzed in golgi apparatus

Ubiquitation: addition of ubquitin proteins, used to designate proteins for degradation in the cell

Protein folding, disulfide bonds, proteolytic processing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

phosphorylation:

A

adding high energy phosphate group to proteins or other molecules by kinase enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Glycolysation:

A

addition of carbohydration moieties to proteins after translation, often catalyzed in golgi apparatus

  • relevant for ABO blood typing; based on presence/absence of A and B glycoproteins on red blood cells

Posttranslational modification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Ubiquitation:

A

addition of ubquitin proteins, used to designate proteins for degradation in the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

After synthesis, proteins folded into 3D conformation by

A

Chaperone proteins in cytoplasm or ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Posttranslational modification

Disulfide bonds

A

Bonds between neaby cysteine residues, linking two parts of a protein

  • Maintaining tertiary structure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Posttranslational modification

Proteolytic processing

A

Cleaved at specific sites, sometimes to generate two separate peptides with unique functions

  • Also activates proteins sometimes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Peptide prohormones cleavage

Why?

A

Preprohormone which is cleaved into prohormone which is cleaved into hormone before relased from cell

** Prevents premature activation, which can be dangerous

ex. Pancreas contains host of proteolytic enzymes for digestion in dormant state

  • only activated in small intestine for digesting proteins
  • in acute pancreatitis become prematurely activated; rampant proteolytic activity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Cells contain same genome but are expressed and regulated differently

A

Diploid human cell contains about 20,000 genes but only express specific subsets at specific times in response to specific stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

During development, complex signaling patterns induce cell differentiation

A

Stem cells into diff tissues and specialized cell types

stem cells: relatively undifferentiated cells capable of differentiating

  • embryonic and somatic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Types of stem cells

A

Mesenchymal stem cells: produce fat, bone, and liver cells

Intestinal stem cells

Hematopoietic: generate blood cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Stem cell potency

A

Limits to their cell differentiation

totipotent: can differentiate to any type of cell

  • in humans, only embryos up to morula or 16 cell stage

pluripotent: capable of differentiating into many different cell types

  • ectoderm, mesoderm, endoderm (primary germ layers)
  • can’t differentiate into cells of placent

multipotent: adult, limited subset of cell types within germ layer

Totipotent and pluripotent can be used for generating tissue and organ grafts, controversial

  • cancer cells can become less differentiated and pluripotency can be artificially induced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Apoptosis

A

Programmed cell death, intentional

  • critical role in embryonic development
    • ex. webbed fingers before apoptosis

Checkpoint for when things go wrong

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Prokaryotic Gene Expression

A

Operon: genetic system used by prokaryotes to regulate the expression of specific genes; under positive or negative control

  • contains regulatory sequence with promoter, and operator

positively controlled gene: genes expressed when activator present

  • activator molecule binds to regulatory gene

negatively controlled gene: genes expressed unless repressor present

  • repressor binds to operator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

lac Operon

A

Negative inducible; expression induced by removal of repressor

negative inducible: default is off, expression induced by specific signal removed repressor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

trp Operon

A

PROKARYOTES (has operon)

Expression is repressed by binding of repressor

  • negative repressible: default is on

Contains genes for synthesis of amino acid tryptophan

  • abundant supply tryptophan represses transcription
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Eukaryotic Gene Regulation/Expression

A

Much more complex. Short sequences recognized by mediator proteins which recruit RNA pol III

TATA box bound by TATA binding protein which associates with other proteins to act as a transcription factor for RNA polymerase

  • transcription factors: bind to specific DNA sequences to regulate gene expression; recruit other regulatory proteins that make chemical modifications to DNA
    • *play pivotal role in activity/identity of given cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Enhancers

A

Gene expression

Sequences which promote enhanced expression of genes in response to stimuli, can be upstream or downstream

  • bind to transcription factors known as activators which twist DNA into a hairpin
    • brings enhancer region closer to gene sequence to facilitate intiation of transcription

ex. estrogen binding its nuclear estrogen receptor, which then binds enhancers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Silencers

A

Gene expression

Sequence that when bound by a repressor, silence or repress expression of genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Types of DNA modification

A

In nucleus, DNA is wound around histones and then condensed further into tightly packed heterochromatin or relatively loose euchromatin

​Acetylation/deactylation: certain enzymes can modify histones by adding/removing acetyl groups

  • affect how easy DNA is accessed
  • histone acetyltransferases: add acetyl groups, makes DNA more accessible for transcription
    • histone deacetyltransferases reduce transcription

Methylation: add methyl groups to cytosine or adenine

  • deactivates gene sequences, preventing their expression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

Epigenetics

A

Heritable changes that affect gene expression without directly changing the genetic sequence

  • Can be transmitted through multiple generations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

RNA interference

A

Non coding RNA that can interfere with gene expression

  • Degrade mRNA prior to translation

- siRNA (double stranded) and microRNA (ss)

siRNA or microRNA incorporated into RNA induced silencing complex (RISC)

  • pairs with complementary target mRNA transcipt, cleaves it
75
Q

Fertilization of an egg by sperm occurs in the

A

Fallopian tubes, unless in vitro fertilization

76
Q

Fertilization steps up until zygote

A
  1. Mature egg released from ovary into abdominal cavity before being swept up by cilia into fallopian tubes
  2. As egg is being transported to uterus, sperm makes its way up fallopian tubes
  • at this point egg is secondary oocyte (undergone meiosis I and stalled at metaphase in meiosis II)
  • Sperm must pass through corona radiata layer of follicular cells and then zona pellucida layer of glycoproteins
    • When sperm head makes contact with particular glycoprotein, triggers the acrosome reaction
      • ​release of digestive enzymes that permit entry of sperm and nuclueus into egg
  1. Secondary oocyte proceeds to complete meiosis II, forming a polar body and a mature, fertilized ovum
    * haploid nuclei of sperm and ovum fuse to form diploid called ZYGOTE
77
Q

Sperm contain abundant

A

Mitochondria to power long journey

  • Any sperm mitochondria that enter egg are destroyed, mitochondria inherited maternally
78
Q

Because the body only wants ONE sperm to interact with egg…

Cortical reaction

A

Once one reaches egg, egg releases cortical granules which cause surface glycoproteins to form cross links which prevent polyspermy

  • fertilization by multiple sperm
79
Q

At the 16 cell stage (after cleavage of zygote), embryo is known as morula

What happens next?

A
  1. Continues to divide into blastula
  • has fluid filled cavity called blastocoel
    • outer layer of cells surrounding blastocoel is the trophoblast
      • ​forms the placenta
  • ​​inner cell mass: mass of cells at one pole of the cell, develops into cells of fetus
  1. As it reaches the uterus, blastula implants itself into uterine wall
  • if zygote implants in fallopian tube or cervix = ectopic pregnancy
    • ​nonviable and can be dangerous for mother
  1. Trophoblast begins forming placenta, inner cell mass begins to form yolk sac and amnion which become the amniotic sac
  2. Firmly implanted in uterine wall, blastula differentiates into a gatrula - undergoes gastrulation
80
Q

Implantation

What tissue does embryo implant in?

A

Requires reciprocal cooperation between embryo and uterine tissue which undergo structural changes and responds to hormonal signals as embryo implants in uterine endometrium in cervix

Trophoblast then begins forming placenta

81
Q

Amniotic sac

A

yolk sac and amnion

Membranous sac containing amniotic fluid which the fetus develops in

82
Q

Gastrulation

A

Formation of 3 primary germ layers

  1. endoderm: internal derm, gives rise to many of internal organs
    * urinary bladder and gastrointestinal and respiratory tracts, epithelial linings
  2. mesoderm: means to move, gives rise to connective tissue, muscle, circulatory system, kidneys, adrenal glands, and gonads
  3. ectoderm: external derm, gives rise to nervous system, skin, eyes, ears, nose, hair, and teeth enamel
    * neurulation: early development of nervous system
83
Q

Neurulation

A

Gives rise to nervous system 1-3 weeks after fertilization

  1. Rod of mesodermal cells form notochord which induces the formation of neural plate from ectoderm cells
    * neural plate invaginates to form neural folds and a central neural groove

2. continues to fold until folds meet and form neural tube

  • neural tube gives rise to central nervous system (brain and spinal cord)
  • neural crest cells will migrate from neural folds to form peripheral nervous system
84
Q

Fertilization cell cycle

A

1. Mature egg

2. Secondary oocyte once in fallopian tubes (undergone meiosis I, stalled at metaphase in meiosis II)

3. Fetilized ovum once gone through meiosis II

4. Zygote: haploid nuclei of sperm and ovum fuse to form diploid

5. Morula: after cleavage

6. Blastula after more division

7. Gastrula once implanted in uterine endometrium in cervix

85
Q

Vitamin D

A

help the body absorb and retain calcium and phosphorus; both are critical for building bone

86
Q

thyrotropin releasing hormone (TRH)

A

Hypothalamic hormone

tells anterior pituitary to release thyroid stimulating hormone (TSH) which tells thyroid to produce T3 and T4

87
Q

ex. gonadotropin releasing hormone (GnRH)

A

Hypothalamic hormone which tells anterior pituitary to release LH and FSH which play roles in reproduction and growth

  • in males LH, stimulates Leydig cells in testes to release testosterone and FSH promotes spermatogenesis
  • in females, LH stimulates estrogen production from ovaries, FSH promotes maturation of ovarian follicles
88
Q

ex. corticotropin-releasing hormone (CRH),

A

Hypothalamic hormone

releases adrenocorticotropic hormone (ACTH) which travels to adrenal cortex and produces corticosteroids: stress response and circadian rhythms

89
Q

Organic separation and purification techniques take advantage of

A

Polarity, solubility, boiling point

90
Q

Extraction (separation technique)

A

Takes advantage of two liquid phases: polar aqueous phase (usually water) and relatively nonpolar organic phase (organic solvent, immiscible with water (don’t mix))

  • liquid half in separatory funnel, denser liquid at the bottom

Like dissolves like, shaking the funnel separates them into polar and nonpolar solutes

**If compound is uncharged and has both polar and nonpolar groups, non polar groups win

  • by using acid base properties, you can add protons to create polarity
91
Q

Can you separate two different acids using extraction?

A

Only if one of the acids is much stronger than the other (lower pKa)

92
Q

Volatile substance

A

easily transitions from liquid to gas phase

93
Q

Simple Distillation (for very different boiling points)

A

Separates liquid by their boiling point using votality and vapor pressure

vapor pressure: pressure exerted by liquid molecules

  1. Round bottom flask with mixture is heated
    1. Liquid becomes gas and rises up to a condensor
  2. Cold water around condensor changes gas back to liquid

Doesn’t always separate perfectly –> REPEAT DISTILLATIONS

94
Q

Molecules with the highest boiling points have

A

Highest polarity: trong hydrogen bonding or dipole-dipole interactions

Largest molecular weight (not as much of priority)

95
Q

Fractional distillation

A

Uses fractional distillation to separate liquids with close boiling points

  1. Increases vertical distance that vapor travels
  2. Allows vapor to recondense and revaporize repeatedly
96
Q

Boiling point

How can you lower the boiling point of a liquid?

A

Vapor pressure of liquid reaches atmospheric pressure

Lower the boiling point by lowering the ambient pressure = vacuum distillation

97
Q

Chromatography

A

In all chromatography, two phases:

Mobile phase: moving fluid or gas

Stationary phase: immobile substance that retains some molecules moving through the mobile phase

Solutes travelling at different speeds based on affinity for mobile and stationary phases

98
Q

Thin Layer Chromatography

A

Can be used to detect impurities in a sample

Stationary phase: glass or plastic plate coated with a thin layer of absorbent material like silica gel (HIGHLY POLAR)

Mobile phase: nonpolar solvent such as hexane, referred to as “eluent”

  1. Spots are placed at bottom of stationary phase plate and just above mobile phase solvent
  2. Capillary action pulls mobile phase up the plate, compounds in the sample will also travel upward

Nonpolar particles travel further than polar (have higher affinity for plate and don’t want to move)

Allows us to make rough measurements of polarity of compounds using Retention Factor (Rf) = distance travelled by compound/distance travelled by solvent

- nonpolar compounds have higher Rf typically

99
Q

Column Chromatography

Different types

A

For larger quantities of material

Stationary phase: solid adsorbent packed in vertial column, sample is added here

Mobile phase: solvent poured through column (eluent)

  1. size exclusion: separate components based on physical size
    1. stationary phase has pore studded beads, larger molecules pass through faster (OPPOSITE of what we’d think)
  2. cation exchange: traps positive molecules, negatively charged stationary phase
  3. anion exchange: opposite
  4. afffinity: ligands designed to bind to molecule of interest are attached to stationary phase
    1. once solution has passed through, dissociate bound compound of interest
  5. gas-liquid: gas mobile phase and sample, liquid is stationary phase
    1. time spent in compound depends on volatility and affinity
    2. smaller compounds have earlier peaks when analyzed
100
Q

Technique used to purify impure crystalline structures that precipitate out of solution

Ideal solvent??

A

Recrystallization

  1. Solid product placed in liquid solvent and heated to dissolve
  2. Mixture cooled again and solid allowed to reform
    1. typically excludes many impurities present before

Ideal solvent is one in which desired product is soluble at high temperature, relatively insoluble in low temp

Often repeated many times over

101
Q

To begin crystallization and recrystallization, requires initial…

A

Nucleation

Nucleus or tiny seed crystal initiates crystallization

Scratch side of glass

102
Q

Spectroscopy

A

Analysis of molecules based on interaction with electromagnetic radiation

103
Q

Electromagnetic radiation and how different types of light interact with molecules

A
  • Lower energy waves, like microwaves, can rotate molecules
  • Infrared waves can cause bonds to stretch and bend
  • Visible and UV waves can excite electrons to higher energy levels
    • some are ionizing, can remove electrons
  • All X-rays and gamma rays are ionizing, which can cause DNA damage
104
Q

Infrared spectroscopy

A

Uses infrared radiation and molecule interactions ***different bonds have distinct ways of interacting with IR radiation

  • ** must be a dipole present, usually polar covalent bonds
    • vibrational frequencies: even those with dipole present, requires specific frequency of IR radiation to stretch or bend

x-axis: differenw wavelengths of IR radiation

y-axis: transmittance (low transmittance means high absorption)

PEAKS ONLY HELPFUL FROM 1500-4000

105
Q

For IR spectroscopy, double bonds with carbon appear at ____

****Carbonyl

Triple bonds are at ___

***O-H bonds are at ___

N-H bonds ____

A

Low frequency (below 2000)

*** Carbonyl at 1650, SHARP PEAK

Medium frequency (low 2000s)

3100-3500 BROAD AND WIDE

3300-3500

106
Q

UV/Vis spectroscopy

y-axis x-axis

A

Electron excitement due to UV light (electrons move to higher energy orbitals)

UV and visible light usually absorbed by molecules with non-bonding or pi electrons

  • conjugated compounds (alternating single and double bonds) are fantastic at absorbing UV light
    • overlapping p orbitals which delocalize

Each molecule has peak absorption values that correspons to wavelengths of light most readily absorbed (opposite of IR transmittance)

y-axis: percent absorbance= proportion of light absorbed by sample

x-axis: wavelength (nm)

107
Q

Beer’s Law (UV/Vis spectroscopy)

A

absorbance is proportional to the path length, b, through the sample and the concentration of the absorbing species, A= α b · c.

A = absorbance

α = molar absorptivity

b = length of light path

c = concentration

Absorbance proportional to concentration

108
Q

Aromatic amino acids and UV/Vis spectroscopy

A

Tryptophan, Tyrosine, Phenylalanine all capable of absorbing UV light through aromatic ring structures (with conjugated pi electrons)

  • each has different spectrum

*** UV spectrum of any peptide depends on aromatic amino content

109
Q

Absorption

UV/Vis spectroscopy

A

Colored compounds absorb some wavelengths of light and reflect others; we perceive an object to have color of the wavelength it reflects

  • UV/Vis spectroscopy is basically identifying compounds based on their color
110
Q

Nuclear Magnetic Resonance (NMR) spectroscopy

2 types

A

Characterizing a molecules atoms (unlike IR which characterizes bonds) by how they interact with magnetic field

  • either spin with field at lower energy or against it

Protons and neutrons have opposite spins that cancel out, if atom as even number than won’t show up on NMR; requires net magnetic moment from unequal spins

1HNMR and 13CNMR

Location on graph depends on shielding and deshielding of nucleus; carboxylic acids and electronegative atoms are deshielding and to the left on graph

111
Q

HNMR steps

A

1. Number of signals (equivalence, H’s bonded to same carbon count as 1)

2. Position of signals relative to most electronegative atoms (oxygens for example)

  • Most shielded are further from EN groups, further right on graph

3. Size of signal: height is proportional to number of protons represented by signal

  1. Shape of signal (splitting): caused by interference with neighboring protons (bonded to a different adjacent carbon)
  • n+1
  • each peak split into number corresponding to hydrogen atoms nearby
112
Q

13CNMR

A

Uses carbon and isotope carbon 13

Same as HNMR except no splitting

  1. FIRST STEP: determine number of equivalent carbons
  • Equivalent carbons are a single peak
    • carbonyl carbon will be much further downfield
    • terminal carbons are upfield
113
Q

Mass spectroscopy

What is most important?

A

Uses magnetism to determine mass

  1. First step is ionization using an electron beam
    1. creates ions and can break apart molecules
    2. parent ion: ion created by loss of just one electron and no fragmentation M+
      1. maintains parent molecular weight but is charged
  2. Accelerate into magnetic field and uses Fb = Bqvsin0 to determine the angle of deflection
    1. separated by mass to charge ratio

y axis is relative abundance, x axis is m/z

*** M+ is the peak furthest to the right and thats how you determine the molecular mass

114
Q

Gel electrophoresis

Which way days DNA migrate

A

Charged macromolecules like DNA or protein are suspended in agarose gel and migrate due to application of electric current

Separates by size or charge

  • Cathode: negative charge
  • Anode: positive charge

DNA negative phosphate groups move towards anode

Can isolate to just size by negating charge of proteins using SDS (anionic detergent) which UNFOLDS and makes neutral charge

  • requires reducing agent to fully denature quaternary/tertiary structure
115
Q

What does SDS do to proteins (SDS-PAGE)

A

Gives them a uniform negative charge for gel electrophoresis

116
Q

Hybridization lab technique

A

ssDNA or RNA to bond with cDNA or cRNA

Used to anneal DNA strands and artificially replicate DNA

117
Q

Blotting

A

Transfer of DNA or protein from a gel to another membrane where molecules of interest can be visualized

  • Southern
  • Northern
  • Western
  1. Sample undergoes gel electrophoresis (proteins mix w/ SDS to neutralize charge) and separation is BY SIZE
  2. Contents transferred to nitrocellulose membrane
  3. Use hybridization to tag sample with visual marker either cDNA/cRNA or a tagged antibody for proteins
  4. Detect molecule of interest with conjugated probe
118
Q

SNOWDROP

A

Southern

Northern

o

Western

DNA

RNA

o

Protein

119
Q

DNA microarrays

A

Uses hybridization to analyze tens of thousands of genes simultaneously on a chip

ex. cancer cells vs healthy cells

120
Q

Sanger Sequencing Method

A

Replication of DNA fragment sample is prematurely terminated using one of the 4 labeled ddNTPs (dideoxynucleoside triphosphates) which each stop for a different nucleotide

  • *** lacks 3’ OH required to extend nucleotide chain

Then different sized strands separated by gel electrophoresis

Requires large number of genetic copies of same sequence – PCR

121
Q

Polymerase Chain Reaction

A

Repeated cycles of DNA sequencing that doubles them each time

  • Can also amplify RNA if it is reverse transcribed

Primers specific to target sequence

  1. Reaction heated to 95 deg C to denature two strands of DNA
  2. Cooled to allow primers to anneal to template strands
  3. Heated again to initiate synthesis by DNA polymerase = Taq polymerase

Heating and cooling done by thermocyclers

122
Q

Protein Purification steps

A
  1. Extract by lysing cellular membranes either by freezing and thawing, solvents, detergents
  • often treated with protease inhibitors to keep lysed proteins from degrading other cells
  • cooled and pH maintained
  1. Separation by centrifugation
  • pellet: heavy dense particles
  • supernatant: proteins usually stay in solution

or by solubility: changing salt concentrations of surroundings

  1. Use chromatography to isolate desired protein
123
Q

Retention factor (thin layer chromatography)

A

High value is nonpolar

Low value is polar

124
Q

Isoelectric point

Isoelectric focusing

A

pH at which protein has a net charge of 0

Separates proteins of different charge states using special gel based on number of basic or acidic residues

  • can be combined with SDS PAGE for 2D gel electrophoresis
125
Q

Primary and secondary antibodies

A

Used for tagging proteins in separation techniques = western blotting

126
Q

Immunoassays

A

Techniques that rely on binding specificities of antibodies to identify proteins

western blotting

radioimmunoassay: conc of protein in sample measured indirectly by looking at unlabeled proteins reacting with labeled antigens

ELISA: antigens in sample are attached to plate and antibodies apply; after washing, amount of bound antibody is measured with fluorescence

127
Q

Replication Crisis

A

Results of many studies cannot be replicated or reproduced in efforts to repeat the studies

Due to methodology – need procedures to be airtight

128
Q

Publication bias

A

Only significant or interesting results are published

129
Q

Observational study design can’t determine

A

Causation

130
Q

Representative sampling

A

Important goal in study design to ensure applicability to real populations (external validity)

Sampling bias: population sampled isn’t representative of population as a whole

The larger the sample size the more likely it is to represent the entire population – increases statistical power

131
Q

To eliminate underlying variables, experimental design must contain

A

Control groups

  • Equal number of sample receive control as do experiment

negative controls: expect a negative result

positive controls: expect a positive result

132
Q

Ways to increase validity of experiment

A

Randomization

Blinding

Controls

Large sample

133
Q

Mediating variable

A

Provide mechanistic link between independent and dependent variables

Help explain relationship

134
Q

Moderating variables

A

Affect the strength of a relationship

Age, gender, socioeconomic class

135
Q

Confounding variable

A

Affect both the independent and dependent variables; obscures the true relationship

  • bigger problem with observational studies

Risk can be reduced by making statistical adjustments for possible confounding variables

136
Q

Systematic review / meta analysis

A

Analyzing the results of multiple randomized controlled trials would give even more confidence in results

137
Q

Non associative learning

A

instances in which an animal’s behaviour toward a stimulus changes in the absence of any apparent associated stimulus or event

138
Q

Baddeley’s model, working memory includes:

A

Phonological loop and visuospatial sketchpad

139
Q

Impulse

A

product of force and time

(kg*m) / s

140
Q

Common types of enzymes

A
141
Q

Acetyl Group

A

Acetyl group contains a methyl group single-bonded to a carbonyl

142
Q

How to know how many stereoisomers there are?

A

If there are 5 chiral centers, 25

2n

143
Q

Temperature and Resistance

A

As temp increases, resistance increases linearly

144
Q

How can enzymes be used to form a single stereoisomer?

A

An enzyme is a chiral catalyst capable of preferentially forming one enantiomer because a lower energy chiral transition state leads to the preferred product

145
Q

Best primers for PCR consist of

A

Best primers for PCR have a high GC content and CG bases in 5′ and 3′

146
Q

In which phase of meiosis does nondisjunction occur?

A

Anaphase I

147
Q

When a striated muscle cell metabolizes glucose in the complete absence of O2, which of the following substances is NOT produced in a significant amount?

A

If oxygen is scarce or absent, the product of glycolysis will be transformed into lactic acid instead of acetyl-CoA. Thus, the cell will produce less acetyl-CoA.

148
Q

mercapto-

A

indicates presence of a thiol group

149
Q

cAMP

A

regulates pivotal physiologic processes including metabolism, secretion, calcium homeostasis, muscle contraction, cell fate, and gene transcription. cAMP is a cyclic nucleotide that serves as a vital second messenger in several signaling pathways.

150
Q

Red litmus paper

A

Red litmus paper is a base indicator. It turns blue at 8.1 pH and higher. While not a measure of pH levels, it’s a quick and accurate way to determine if a solution is alkaline

151
Q

Transition metals and color

A

The color arises because nickel(II) ion has partially filled d orbitals and the electrons in the lower energy d orbitals absorb visible light to move to the higher energy d orbitals.

152
Q

The retention factor of a particular material is the ratio of the distance the spot moved above the origin to the distance the solvent front moved above the origin

A

Lower for more polar molecules for a polar starting material

153
Q

Electric field can be given in (units)

A

V/m

154
Q

The period T and frequency f of a tone are related by

A

T = 1/f.

155
Q

Methylation of DNA

A

Methylation: add methyl groups to cytosine or adenine

  • deactivates gene sequences, preventing their expression
156
Q

Sn2 reactions cause

A

an inversion of stereochemistry (R to S or vice versa)

157
Q

The energy of electromagnetic radiation is directly proportional to

A

the number of photons, and the intensity of electromagnetic radiation is defined as energy emitted per unit time. Thus, intensity is directly proportional to the number of photons emitted

158
Q

In glycogen, branching is due to the formation of

Which type of bond is formed by glycogen synthase upon release of UDP?

A

α−1, 6-glycosidic bonds

α-1,4-Glycosidic bond

159
Q

Type II errors are

A

false negatives

160
Q

Two types of sensory memory

A

Echoic memory: the ultra-short-term memory for things you hear.

Iconic memory: involves the memory of visual stimuli.

161
Q

Fovea

A

a small depression in the retina of the eye where visual acuity is highest. The center of the field of vision is focused in this region, where retinal cones are particularly concentrated.

162
Q

Nomenclature of alkanes

A

CH4 - methane

C2H6 - ethane

C3H8 - propane

C4H10 - butane

pentane, hexane, heptane, octane

Substituents in alphabetical order before parent chain

ex. 3-ethyl-4,5-dimethyloctane

163
Q

Parent chain =

A

Longest/most C’s in a way that results in lowest possible #’s for substituents

164
Q

GLUT 1 transporter

A

Nearly all tissues, especially fetal, erythrocytes, and cancer cells

  • Baseline cellular uptake, expression increases when glucose is low
165
Q

GLUT 2 transporter

A

Liver, kidney, pancreatic B cells

  • Bidirectional transport for glycolysis, glycogenesis, gluconeogenesis
  • Uptake and export
166
Q

GLUT 3 transporter

A

Neurons, placenta

  • High glucose affinity, transports glucose into cell even when extracellular concentration is low
167
Q

GLUT 4 transporter

A

Skeletal and cardica muscle, adipose tissue

  • Storage as glycogen or triglycerides, upregulated by glucose and insulin
  • insulin sensitive

Type 2 diabetes- GLUT4 becomes insensitive to insulin, stops being expressed at normal insulin levels

168
Q

Bond order

A

Total number of bonds in molecules divided by the number of BOND GROUPS (i.e. one double bond and one single bond = 2 bond groups) they are connected to

169
Q

Peptide bond resonance

A

Resonance in peptide bonds causes:

  • planar geometry
  • restricted rotation of peptide bonds
  • exceptional stability of amides
170
Q

Conjugation (pi systems)

A

3+ pi orbitals (double bonds) align with eachother

  • Electrons delocalize throughout
  • Absorbs UV light, easily detected by UV spectroscopy

Much more stable, lower energy

171
Q

Priority from highest to lowest

A

1. Carboxylic acid carboxy- -oic acid

2. Ester RCOOR’ oxycarbonyl- -oate

3. Acid halidesRCOX halocarbonyl- -oyl halide

4. Amide carbomoyl- -amide

5. Aldehydes oxo- -al

6. Ketones oxo- -one

7. Alcohols hydroxy- -ol

8. Thiols mercapto- -thiol

9. Alkanes

10. Ethers

172
Q

Ring nomenclature

Benzene substituent nomenclature

A

cyclopropane (3 carbons), cyclobutane

  • constrained rings highly unstable
  • phenyl
173
Q

Branched alkanes have lower ____ than linear alkanes

A

boiling points

LARGER alkanes have higher boiling points

  • Alkanes generally low melting and boiling points = VOLATILE

- only london dispersion forces

174
Q

Halides are

A

very reactive, great leaving groups

175
Q

Alkenes and alkynes are more ____ than alkanes

A

REACTIVE

Double and triple bonds have extra electron density, act as nucleophiles in reactions

176
Q
A
177
Q

Aromaticity and Huckels Rule

What molecules are aromatic

A

Electron delocalization, fully conjugated ring

  • Huckels rule: 4n + 2π electrons

* each double bond is 2 pi electrons

Benzene has 3 double bonds, 6 pi electrons

4n + 2 = 6

n= 1

178
Q

Environmental influence on behavior

A

Genes expressed more or less with environemtnal stimuli

  • DNA promoters initiate expression of some genes
  • Regulatory genes code for proteins that affect gene expression

Theory that variations could affect behavior

  • ex. Allele in gene for promoting serotonin makes people susceptible to depression
179
Q

Epigenetics

A

Changes to genome that don’t involve changing actual nucleotide content

ex. methylation of cytosine silences specific genes
- stress, exercise, heritable

180
Q

Nature vs. Nurture

A

Characterizing heritability (how much is a trait determined by genes alone) of a trait

  • Slope = 1
    • all variation from genetics
  • Slope = 0
    • environmental factors/ chance

Pyschological trait heritability: .3-.6 (genetic and enviuronmental factors

  • Schizophrenia = .8
181
Q

Study design for heritability (nature vs. nurture)

A

Twin studies - monozygotic and dizygotic

Adopted children- genetics of real parent but environment of foster

182
Q

monozygotic twins for zygotic twins

A

Monozygotic twins are formed by one sperm and one egg. Dizygotic twins are formed by two different sperm and two different eggs

Monozygotic = identical

Dizygotic = fraternal

183
Q

Molecular geometry chart

regions of electron density -2, 3, 4, 5, 6

A

MCAT (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions