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Biology 1 Flashcards

1
Q

The intermembrane space has a ___er pH than the matrix

  • Therefore, the intermembrane space is more ____
A

lower pH than matrix

intermembrane space is more acidic

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1
Q

Tissue organization: ___>___>___>___

A

Organ systems>Organs>Tissues>Cells

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1
Q

Tetrads line up SINGLE-FILE at metaphase plate

A

Metaphase of Mitosis

Key word: “Single File”

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2
Q

What are the 3 main functions of PEROXISOMES?

A
  1. Self-replicate
  2. Detoxify chemicals
  3. Participate in lipid METABOLISM
    • along with mitochondria
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3
Q

What are the 2 HARDY-WEINBERG Formulas we need to know?

A

p2+2pq+q2=1

p+q=1

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3
Q
  • Mitosis
    • Prophase
A

During prophase:

  • the nuclear membrane dissolves
  • the chromosomes condense
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3
Q
  • Mitosis
    • Telophase
A

Telophase

  • is indicated by:
    • the nuclear membranes beginning to reform and
    • the chromosomes unwinding
    • Formation of the NUCLEOLUS

​

Many diagrams will also show the beginning of cytokinesis

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4
Q

What are Heterotrophs?

A
  • UNABLE to fix CO2 (like autotrophs can)

Therefore, heterotrophs must INGEST organic molecules (such as carbohydrates) as their carbon source

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5
Q

Non-nuclear DNA is found where?

A

mitochondria

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5
Q

What are 4 characteristics about the NUCLEUS?

A
  1. Where DNA is
  2. DNA cannot leave nuleus
  3. Is by a dual bi-layer membrane
    1. one bi layer is continuous with ER
  4. contains nuclear pores
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5
Q

DNA replication

  • Describe DNA ligase
A

Creates the LAST necessary PHOSPHODIESTER bond to the downstream neighbor

thus creating a COMPLETED strand! Yayyy!!!

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6
Q

What is the Endosymbiotic Theory?

A
  • suggests mitochondria evolved from aerobic PROkaryotes
    • …that were engulfed by an ancient EUKaryotic cell (common ancestor)
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7
Q

Causes of DNA Damage

  • Mismatched Base pairs result from (2)?

HINT: One of the 2 causes results from a specific thing happening to a specific NT…

  • Give an example of this happening (with actual BP’s, not a real-life example)
A

Results from:

  • Errors during replication, or
  • Methylation of guanine

ex: one form of methylated guanine pairs with thymine INSTEAD of cytosine…whoopsy daisy

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8
Q

Define a Membrane receptor

A

any protein that specifically binds to a signaling molecule (ligand)

  • …and initiates a cellular response
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8
Q
  • In order for natural selection to occur, what 2 things must happen?

HINT: Polymorphisms (discontinuous genetic variation)

A

1) An individual MUST have a polymorphism that provides an evolutionary fitness advantage
2) This advantage MUST result in the individual with the favored polymorphism

…differentially** **producing MORE offspring!

  • ​its good to be different!
  • Give a species resistance against illness & stuff
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8
Q

GLIAL CELLS, such as:

  • Astrocytes
  • Schwann cells
  • Oligodendrocytes
  • Ependymal cells

are also considered to be what?

  • Also! Remember that EPENDYMAL cells contain…?
A

NERVOUS tissue

EPENDYMAL cells contain CILIA!

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8
Q

DNA replication: sliding clamp

A

protein that keeps DNA poly tightly bound to strand

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9
Q

How does reproduction work in Prokaryotes (Bacteria)?

  • How does the distribution of DNA work?
A

Bacteria reproduce via binary fission

NO mitosis OR meiosis!

Distribution of extrachromosomal DNA (aka plasmids) is RANDOM

  • Daughter cells may or may not receive a copy
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10
Q

Define Western Blot

  • Are used for segments of ______?
  • What are used as probes?

HINT: W-e-s-t-e-r-n has 7 letters, as does the thing it sequences….

A
  • is for PROTEIN segments
    • instead of NT segments
  • Radioactive antibodies are used as probes
    • instead of NT sequences being used as probes
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10
Q

What is PINOCYTOSIS?

A

invagination of:

  • extracellular fluid
  • very small particles

occurs in ALL cells

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11
Q

Define: Actin

A

a protein monomer that polymerizes to form MICROFILAMENTS

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11
Q

How does mRNA interact with DNA?

A

is the complementary RNA strand

…COPIED FROM the DNA template strand

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13
Q
  • What are the 6 possible destinations for ALL proteins?
    • Where are all these proteins made?
A
  1. ER
  2. Golgi
  3. Lysosomes
  4. Endosomes
  5. Plasma Membrane
  6. Extracellular secretion

made in: RER

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13
Q

How many layers must you go through to get from outside of the cell to the nucleus?

A

6 total

  • 2 for cell membrane
  • 2 for outer nuclear membrane
  • 2 for inner nuclear membrane
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14
Fungi have cell ___ made of \_\_\_
cell walls made of chitin
15
What are **Integral** proteins? * What is its opposite?
Proteins that have one or more segments **embedded** within **each** **phospholipid bilayer** * opposite=surface/peripheral proteins
16
What **2 things** exhibit the **9+2 arrangement**?
**Euk**aryotic: ## Footnote **Cilia & flagella**
16
Compare **PROPHASE** for: * **meiosis I** and **mitosis**
**Meiosis I:** * Tetrads are visible **paired up** with e/o as nuclear membrane **dissolves** **Mitosis:** * Chromosomes **ARE** condensed, but **ARENT** **paired**
16
Chromosomes generally \_\_\_\_\_in size, with ______ being by far the largest
generally DECREASE in size, with chromosome One being by far the largest
17
The **Cytoskeleton** consists of?
1. Micro**tubules** 2. **Intermediate** Filaments (IMF's) 3. Micro**filaments**
18
In **gene regulation**, **regulatory** molecules are often what 3 things?
**_Regulatory molecules are often:_** 1. **Hormones** 2. **Upstream products** of rxn or cascade that is catalyzed by gene product 3. **Byproducts** that build up when the [] of the gene product is low
18
If **90 out of every 1,000** individuals in a population have a **RECESSIVE** phenotype **(tt)** * what % of pop is **TT, Tt,** and **tt?** **​(Solve using HW equations)**
* 90/1000=.09 √.09=.3 * therefore **q=.3** * since p+q=1 * p = **.72** * pg=2(.3)(.7)=.**42** * p2=(.7)2=**.49** * therefore, **49% of pop have genotype TT** * 42% are Tt * 9% are tt 70% of alleles are p and 30% of alleles are q
20
How many **protofilaments** surrounding a hollow core make up a **microtubule**?
**13**
21
What are **Adherens junctions?**
**STRONG,** **MECHANICAL** attachments b/t cells
22
* Meiosis **I** * Interphase I
23
Post-translational modification: * usually **occurs** at? * what are some **common** modifications?
* Occurs at: * **ER** and the **Golgi** Includes **ADDITION** of: * polysaccharides * lipids, or * phosphates
24
Compare **anaphase** for **meiosis I** & **mitosis**
**MITOSIS**: * **SINGLE** CHROMATIDS are pulled to opposite ends of cell **MEIOSIS** **I**: * **TETRADS** are pulled to opposite ends of cell
25
Cell **Communication**: * Describe **Endocrine**
**HORMONE SIGNALING** Hormones **made** & **secreted** by cells in **endocrine** gland, then * **Travel** in bloodstream * **Bind** to receptors either on: * cell **surface** * for **water**-soluble hormones * **inside** the cell * for **lipid** soluble hormones
26
Name **Mendel's** Laws (2) * Law of...
1. Law of **Segregation** 2. Law of I**ndependent Assortment**
26
What is **Bidirectional (DNA replication)?**
* Refers to fact that DNA replication proceeds in **both** directions (5→3, 3→​5) **simultaneously** * Starting from the origin
28
**Lysosomes** * Have a pH of *what*? * What are the 3 main functions of Lysosomes?
* **pH of 5** _Functions:_ 1. **Digest** cell parts 2. **Fuse** with **phagocytotic** vesicles 3. participate in **apoptosis**
29
* Mitosis * Metaphase
Metaphase is indicated by: * the **chromosomes lining up at the metaphase plate** and * **formation of the spindle apparatus**
30
What happens to **cholesterol** in the **cell membrane** at **lower** temperatures?
At **LOWER** temps: * Non-polar **tails** of lipids could **interact** and cause **crystallization** * *WHICH IS BAD* * The rigid **steroid portion** of CHO **disrupts** VDW forces between lipid tails tails * which maintains (just enough) FLUIDITY
30
**Genetics**: * An individual having two **different** alleles of a particular gene or genes * and so giving rise to **varying** offspring *Would be a...?*
**HETERO**zygote
31
\_\_\_\_ is ALWAYS req'd to move something against its [] gradient or against an electrical potential
active transport
31
Describe: **HypOtonic** solutions
**LESS** concentrated than the cell * driving water to **ENTER** the cell * it might **BURST**! ***water⇒cell***
31
Cellular Junctions * Describe **TIGHT** Junctions
are ***water-proof barriers***
31
Cell Cycle: * Describe the **G1 Phase** * Most active cells ___ and ___ within this phase
_**First** growth phase_ * most active cells **LIVE** and **FUNCTION*** * while in this phase* * Cell **grows a ton** in **size** during G1!
32
Describe what happens during **CROSSING-OVER** * **When** does Crossing-Over occur?
**TETRADS PAIR UP** with one another and **exchange segments of DNA** _Occurs during **Prophase 1** of **Meiosis**_
33
The **NUCLEOLUS** is the site of what 2 things? *Nucleolus= Nucleus **WITHIN** the Nucleus!* ***Nucleinception***
**_NUCLEOLUS_:** Site of: 1. **rRNA** TRAN**SCRIPTION** 2. **Ribosome** assembly
34
Mechanisms of DNA Repair: * Describe **Proofreading**
* DNA polymerase **catches** and **repairs** most mismatched base pairs... ## Footnote **_RIGHT_ AS IT HAPPENS!**
35
Phases of Mitosis: * What phase is it if you see: * a **single** cell * with a **well-defined** nuclear membrane and * **uncoiled** chromosomes?
**INTERPHASE**
36
Lipids are made/ **synthesized** in the \_\_\_\_\_, but **metabolized** in the \_\_\_\_\_
* made in **SER** * metabolized in the **mitochondria**
37
Bacterial growth * Bacterial colonies grow \_\_\_\_\_\_\_\_, ​\_\_\_\_\_ each generation * Wrt Bacterial growth, there is a **LIMIT** to *what*? * Why is this limited?
* Bacterial colonies grow **EXPONENTIALLY** * **​doubling** each generation _**HOWEVER**, there is a **LIMIT** to colony size!_ * This is because: * Food and resources **decrease,** and * Waste **accumulates**
37
What are **ISOTONIC** solutions? * Which direction does water flow?
**have an equal [] as the cell** * so there is **NO** net flow of water in **EITHER** direction
38
**DNA** is a polymer of **WHAT?**
**DEOXYRIBOSE** nucleotides
39
Why would fungi alternate b/t **sexual** & **asexual** reproduction? * Basically, what are the pros & cons of each?
Sexual is **hard** * but provides **BETTER** diversification Asexual is **easy** (in terms of energy) * but provides **NO** diversity
40
How many **primers** do the **Leading** and **Lagging** strands require, respectively?
The **Leading** strand * only needs **ONE** primer The **Lagging** strand * needs **MULTIPLE** primers * one for each okazaki fragment
41
Define the **Spindle apparatus**
**_SPINDLE APPARATUS_** * is **array of MT's** that grow outward* * from centrioles during mitosis* * centrioles bind with centromeres * **induce division** of a tetrad * into **separate** chromosomes
42
Describe the 4 steps of **PCR** * What does **HEATING** the DNA do? * Where do you add **Taq Polymerase?** * What does **COOLING** the mixture do?
1. **Heat** DNA * denatures helix 2. **Add** primers * using **Taq** polymerase 3. **Cool** mixture * this anneals (recombines) primers 4. **Heat** again Polymerase then **copies** DNA * making 2 **new** DNA helices * repeat many times over*
43
Where in the **KIDNEY** are the following: * renal medulla * renal pelvis * ureter * nephron * renal cortex
**_Nephron_**: is mostly in renal **CORTEX**, but dips down into the renal **MEDULLA** as well
44
The **Smooth** **ER** is the site of?
Site of lipid **synthesis**/**modification** (but NOT the site of lipid **metabolism**!)
44
DNA replication: * What do **Single-Stranded Binding Proteins** (SSBP's) do? 2 things
1. **COAT** the individual strands 2. **PREVENT** them from re-annealing (unwinding)
45
Main components of all viruses: * What 2 things do **ALL** viruses contain?
**_ALL VIRUSES HAVE:_** * Some form of **NUCLEIC ACID** * RNA or DNA * but _never_ **BOTH** * Plus **PROTEINS**
46
* Mechanisms of DNA Repair: Describe (in general) how **Nucleotide excision repair** works * **​**What gets **removed**? * Is that the **ONLY** thing that gets removed? * What does the **repairing**?
**_NUCLEOTIDE EXCISION_** * Removal of an **oligonucleotide** * ...that **includes** **SEVERAL BASES** on* ***EITHER** side of the error! (look at pic)* * **DNA poly** & **ligase** repair the missing segment
47
Molecular cloning: * What is a **vector?** * Often, the vector is a \_\_\_\_\_
* is a **segment of DNA** used to **transfer** a desired sequence into another cell * often, the vector is a **plasmid***
48
Name the 4 types of **Cellular Junctions?**
1. **Tight** Junctions 2. **Gap** junctions 3. **Adherens** junctions 4. **Des**mosomes
49
Mechanisms of DNA Repair: Mismatch repair system
enzymes that scan newly copied DNA and locate, remove, and replace mismatched base pairs that DNA poly misses during proofreading
50
Apoptosis
programmed cell death, courtesy of lysosomes
51
**Mitochondria** have their own \_\_\_? * How are these passed down?
* Have their **OWN** DNA and variations to nuclear genetic code * Mitochondrial genes are passed down through **MATERNAL LINE ONLY**
52
How are **PHOSPHOLIPIDS** formed? * What **3 things** do you **COMBINE?**
​1 **GLYCEROL** **+** **2 FA's** **+** **1 PO42-**
52
Define: transport proteins
**Integral proteins** that span **entire** width of bi-laye _Create **tunnels** for the passage of:_ * ions * proteins, or * other substances ...**through** the **hydrophobic core**
52
Genetics: * An individual who carries two **identical** copies of the **recessive** gene is...?
**HOMO**zygous **RECESSIVE**
52
tRNA
is the molecule that bridges gap b/t mature mRNA and assembled protein
53
Cause of DNA Damage: Damage by external chemicals or radiationgive an example
when exposed to radiation, neighboring pyrimidines (C or T) react with e/o to form a covalent dimerex: carcinogens are cpds that bind to DNA and create bulky side groups
54
What **IS** the Cytoskeleton? (What does it **DO** for the cell?)
***Is a scaffolding-like network of microfilaments, microtubules, and IMF's*** * gives **structure** to cell * creates a "**highway**" * ...for intracellular **transport**
55
Cause of DNA Damage: Spontaneous hydrolysisgive an example
DNA reacts in solutions w/o external stimulus or chemicals ex: amine groups on DNA bases can react with water to form a carbonyl; via hydrolysis the entire DNA base can be replaced with an OH group
56
How many chromosomes do humans have...during interphase
46
57
DNA polymerase can only add to an existing ______ group
3' OH group
58
Commensalism
form of symbiosis in which one participant benefits and the other's experience is neutral (not good, not bad. It's whatevs)
59
Human taxonomy"All Cool Men Prefer Having Heavy Sideburns"
AnimaliaChordataMammaliaPrimatesHominidaeHomo Sapiens
60
Differences b/t DNA & RNA (4)
-RNA has a 2' OH group, DNA does not-RNA is single stranded, DNA is double stranded-RNA has uracil bases, DNA has thymine basesRNA exits nucleus into the cytoplasm, DNA always stays in nucleus
61
Define: Phospholipids
* lipid molecules with a **non-polar tail*** * and a **polar phosphate head*** * Make up a **bilayer** of a cell membrane
61
Basic structure of bacteria
Capsule, peptidoglycan cell wall, plasma membrane, no complex-bound organelles, single circular DNA chromosome, tiny circular DNA molecules called plasmids
62
Phototrophs
can capture their own energy directly from the sun via photosynthesis
63
Kinetochore
specialized group of proteins to which spindle fibers attach during mitosis/meiosisoften, kinetochore is used synonymously with "centromere"
64
Define: ampiphatic
when a molecule has both polar and non polar regions (like a lipid bilayer)
65
Homologues are?
two related, but non-identical chromosomes--one originating from EACH parent
66
How many chromosomes in a diploid cell?
46
67
Fluid mosaic model
On phospholipid membrane, there are two opposite facing leaflets with polar tails of the phospholipids directed towards center of bi-layer & polar heads sticking outward-creates both a cytosolic & extracellular face
68
What does "quiescent" mean? What's an example of this?
Means stable, not changing, & unlikely to changeex: G0 phase of cell cycle
69
Aerobic respiration reactants (2) & products (3)
reactants: glucose & oxygenproducts: CO2, water, ATP
70
Anaerobic respiration reactants & products
Reacs: Glucose, electron acceptor (anything BUT oxygen)Products: CO2, whatever "thing" (which gets reduced), and ATP
71
Sister chromatids are?are they identical?
2 strands of DNA in a duplicated chromosome attached by a centromerethey are identical only if crossing over has NOT occured
72
In short, crossing over does what?
takes a father's and mother's chromosomes & swaps segments of them, thus creating new combinations of alleles on chromosomes
73
Bacteria reproduce via ?
Binary fission
74
Mitosis vs. Binary fission (bacteria)
Mitosis: very complex. Barring any errors, mitosis delivers an exact and equal amount of DNA to each new daughter cellBinary fission: circular DNA is copied and attached to the membrane. Cell splits, pulling the 2 copies apart and each new daughter cell gets one copy of the chromosome
75
Bacilli are ___ shaped bacteriaCocci are ___ shaped bacteriaSpirilla are ___ shaped bacteria
rodsphericalspiral
76
What is **Tubulin?**
* a **globular** protein that **polymerizes** to form **MICROTUBULES**
77
Aerobic leads to complete ____ of respiratory materialproduces ___ ATP per \_\_\_
complete oxidation of respiratory materialproduces 38 ATP per glucose
78
Origin of replication
is the location on the chromosome where replication begins
79
What fills the gaps made when RNase H removes the RNA primers?
DNA polymerase
80
According to the H-W, what are the 5 conditions that will ensure evolution doesnt happen?
1) Large population2) no mutation3) no immigration or emigration4) random mating5) no natural selection
81
Hardy-Weinberg Equilibrium states that...
allele and genotype frequencies in a population will remain constant from generation to generation in the absence of evolutionary forces
82
Centromere
region of the chromosome that joins the sister chromatids
83
Mechanisms of DNA Repair: Base excision
the base portion ONLY is removed, first via a DNA glycosylase.other enzymes remove sugar-phosphate backbone, then DNA poly and ligase repair the NT
84
Define nondisjunction. What does it result in? What's a real-life example of this?
when chromosomes fail to separate properly during anaphaseresults in uneven # chromosomes--either monosomy (missing chromo) or trisomy (extra chromo) ex of trisomy: Down's
85
Name the 3 causes of DNA damage
1) Spontaneous hydrolysis2) Damage by external chemicals or radiation3) mismatched Base pairs
86
TelomerASE is?
an enzyme that adds length to the telomeres
87
Binary Fission (bacteria): remember that prokaryotes contain?
extrachromosomal DNA (plasmids)There's no system for segregating this DNA, so each daughter cell may or may not get certain plasmids based solely on random chance
88
When (at what phase of what) does crossing-over occur?
occurs during prophase of meiosis I
89
What phase? mitosis or meiosis? I or II? tetrads ("4") are visible paired up with e/o as nuclear membrane dissolves
prophase of meiosis I
90
What role does cholesterol play?
Adds rigidity and fluidity to the membrane
91
Define: Intermediate Filaments (IMFs)
Several proteins that polymerize to form **filaments** that are: * **INTERMEDIATE** in diameter b/t: * micro**filaments** (smallest) * micro**tubules** (largest)
92
Diploid cell has __ chromosomes
2n
93
G protein cascade: What activates protein kinase A (PKA)?What does PKA do?
-cAMP-PKA phosphorylates proteins, usually enzymesBOOM! Cascades
94
Remember that all bacteria are \_\_\_\_\_\_
prokaryotes
95
Why is G0 phase of interest in the MCAT?
-b/c fully-differentiated neurons & cardiac muscle cells are frozen in G0 and do not divide-Multi-nucleated skeletal muscle cells are also in G0
96
DNA replication: What is the helicase?
it unzips the double-helix
97
Define: cancer
uncontrolled cell division due to failure of cell's normal regulatory patterns
98
Tools scientists use to determine taxonomy (5)
1) embryology- often two organisms have similarities that are only present during embryological development 2) Phylogeny- a shared evolutionary history can reveal similarities3) Anatomy4) DNA sequencing 5) Fossils- can reveal traits that were once shared but have since been lost
99
Sex-linked chromosomes: male=?female=?
male=Xfemale=Y(draw a punnett square)
100
name the Mechanisms of DNA repair (4)
1) proofreading2) mismatch repair system3) base excision4) NT excision
101
Phases of Mitosis: Anaphase
here, chromosomes separate and migrate towards the opposite ends of the cell
102
Methods of cell communication (6)
1) Endocrine2) Paracrine3) Autocrine4) Intracrine5) Juxtacrine6) Nervous System
103
What are **Cilia?**
**protrusions** found in: * the **lumen**-**facing** side of **EPITHELIAL** cells lining various cavities in the body
104
Typical phenotypic ratio for a dihybrid cross
9:3:3:1
105
Cytoskeleton * Define a **Microtubule**
* one of 3 parts of cytoskeleton of cell * Made up of **13 protofilaments** * **​**which are made when **ß** and **α-tubulin** form a **heterodimer**
105
Define "mutation"
any change in the DNA sequence
105
Lichen: symbiosis b/t what?
b/t fungi and algae
105
Hypertonic solutions
more concentrated than the cell, driving water to LEAVE the cellSHRINKS!
105
G protein cascade: Alpha subunit does what?
-binds both GTP and GDP-activates cAMP (which converts ATP to ADP + 2Pi)
105
Semi-discontinuous (DNA rep)?
refers to fact that one strand (leading strand) is synthesized continuously, which the other strand (lagging) is synthesized in okazaki frags (is discontinuous)
105
Telomeres are?
-long sections of repetitive DNA NT's found at both ends of each chromosome-provide a buffer regions of non-coding DNA so that the repetitive losses in length don't impact the gene sequence
106
When forming **PHOSPHOLIPIDS**, how does the reaction work? * What does the glycerol do to the FA? * What happens as a result? * What NEW thing is formed?
FA is a long chain carboxylic acid * one of the OH groups on the **glycerol** attacks the **carbonyl carbon** * **kicking off** a H20 molecule * & forming a new **ester** group
107
Eastern Blot defwhat do probes bind to?
used to verify post-translational modification-probes bind to lipids, carbohydrates, or phosphates (the 3 most common post translational modifications)
108
Muscle tissue
includes skeletal, smooth or cardiac muscles found anywhere in the body
109
G protein cascade: alpha subunit does what?
binds both GTP and GDP
110
Phases of Mitosis: Telophase
here, nuclear membranes begin to re-form and chromosomes unwind
111
What's the difference b/t: **Eukaryotic** vs **Prokaryotic** **Flagella?**
**Eukaryotic**: * *whipping* motion * microtubules * made of **tubulin** **Prokaryotic**: * *spinning/rotating* motion * simple helices * made of **flagellin**
112
Fungal reproduction (4)
-fungi spend the majority of their life as a haploid (have a single set of unpaired chromosomes)-fungi grow via long, intertwining branches called hyphae (which are haploid)-Yeasts reproduce almost exclusively by budding-Most fungi can reproduce both sexually (what life is hard...stress, little food, etc) or asexually (when life is good)
113
Tissue types (4)
1) epithelial2) nervous3) connective4) muscle
114
How many chromosomes do humans have...before replication?
46
116
Gene regulation: rate of transcription
RNA has a short half-life, so gene products will only continue to be expressed if DNA is continually transcribed
117
What stage? Mitosis or meiosis? I or II?chromosomes condensed, but not paired
prophase of mitosis
119
Pinocytosis is non-\_\_\_\_, whereas phagocytosis is always \_\_\_-mediated
non-specificreceptor mediated
120
Fungi (3 examples)
mushrooms, yeasts, and molds
121
How do lysosomes **FORM**?
by **budding off** from the Golgi
122
Meiosis I takes a cell with __ homologous chromosomes (or\_\_ totoal chromosomes) and creates?
23 homologous chromosomes, or 46 total chromosomescreates 2 cells, each with 23 non-paired, non-homologous chromosomes
123
**Post-translational modification** * **Starts** where and * **Continues** on to where? Give 2 examples of PTM's
* Starts in **RER** * continues on to **Golgi** ex: disulfide bonds, glycosylation
124
Genetic Regulation: * Describe the **LAC OPERON** * ​**What** does it regulate? * What does the thing it regulates **DO?**
Regulates **EXPRESSION** and **TRANSLATION** of **LACTASE** in bacteria (E. coli) * Lactase is the enzyme that **digests lactose** _Remember_: * Bacteria do much more **anaerobic** respiration (**fermentation⇒lactose**) * so they will have a **MUCH** larger problem if lactose starts building up than if it were to happen in humans
125
Cell Cycle: M phase
mitosis happens during this phase
126
Mendel's Laws: Law of Segregation
alleles segregate independently of one another when forming gametes
127
Describe the **CENTROSOME** (3 things)
**_CENTROSOME_:** * Is an **amorphous** area of proteins which contain **CENTRIOLES** * Organizes: * microtubules * flagella * cilia * Plays a role in **APOPTOSIS** (cell death)
128
Autotrophs
capable of fixing CO2, and can therefore use CO2 as their carbon source for synthesizing organic molecules
129
Define: **Microfilament**
* part of cytoskeleton * also forms the **"thin filament"** portion of **sarcomere**
131
Parasitism
symbiosis where one participant benefits at the expense of the other (other participant IS harmed!)
132
Typical phenotypic ratio for a monohybrid cross
3:1
133
Gap Junctions
tunnels b/t adjacent cells, which allow exchange
134
Molecular cloning: recognition sequence
is the specific base sequence recognized by the endonuclease
136
Stages of Anaerobic respiration (3)?This is the same as in what else?
glycolysiskrebs cycleETC (same as in aerobic respiration)
137
G protein cascade: How do you shut down the cascade? (one way)
-Beta & gamma subunits re-bind with alpha subunit, deactivating it
138
Desmosomes
STRONGEST of cellular junctions-they weld cells together, protecting against stress-are NOT watertight (only tight junctions are)
139
Epithelial tissues
form the linings of the outside of the body, as well as various cavities INside the body. if it is lining a cavity or separating the body from the external environment, consider it to be epithelial tissue
140
When DNA is replicated, the ____ \_\_\_ does NOT change---you just end up with twice as much ___ per \_\_\_
chromosome number doesnt changetwice as much DNA per chromosome
141
Phases of Mitosis: Metaphase
here, chromosomes line up at the metaphase plate and form the spindle apparatus
142
Chromosomal Mutations: (4)
-duplications (non-disjunction)-deletions (non-disjunction)-translocations-inversions
143
Define: Cholesterol
-an ampiphatic molecule with a steroid region and a polar region-inserted in b/t phospholipids in high []s in euk. cells
144
Molecular cloning: restriction nucleases
enzymes that cut DNA at specific pre-determined sequences
146
What makes **CILIA** different from **FLAGELLA?**
*Cilia are **NOT** used for locomotion **of the cell itself*** * Cell is **fixed** in place * Cilia creates a **beating** pattern * that moves fluid and **other** things **PAST** the cell
147
ATCGWhich are purines & which are pyridines?
GA= purines (General Authorities are pure)CT= pyrimidines
148
Genetics: * Any... * **VARIANCE** from expected ratios, or * **RANDOM** **ASSORTMENT** *Suggests WHAT?*
***LINKAGE!***
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What does **REVERSE TRANSCRIPTASE** do? * What **"****idea"**does reverse transcriptase**VIOLATE?**
**REVERSE TRANSCRIPTASE** * Found in **Retroviruses** * Translates its **RNA** nucleotide sequence into **DNA** * **​**because RNA **wasnt able** to be inserted into the host's genome **RNA⇒DNA** **_VIOLATES THE CENTRAL DOGMA OF MMBio:_** The "central dogma" of molecular biology describes the **flow** of genetic information in cells from: **DNA⇒RNA⇒protein** * It states that **genes** specify the sequence of **mRNA** molecules * which in turn specify the sequence of **proteins**
150
Cell Communication: Nervous system\*this method often involves what?
Communication b/t cells via electrical potentials carried on neurons\*these often involve cascades, too. Neurotransmitters bind to receptors on post-synaptic membrane, which initiates a signal
151
Phagocytosis
-type of endocytosis-refers to invagination of very large particles, bacteria, etc-only happens in a few types of cells
152
Fungi traits
all fungi are heterotrophs. Most are saprophytic (live off dead, decaying matter), but a few are parasitic (live off live host, killing it), or mutualistic (symbiotic relationship)
153
Molecular cloning: hybridization means what?
means to join together to form a single strand
154
Genetic probabilities: "EITHER/OR"
If EITHER event occurring fulfills the requirement, add the probabilities of each event occurring individually
155
How many chromosomes do humans have...after replication
46
156
Nervous tissue
neurons of central & peripheral nervous systems
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* Each time a DNA strand is replicated, the **new** strand is **always slightly** ____ that the parent strand * Why is this?
**SHORTER** * b/c DNA polymerases need an existing **3' OH** group ***to add their first NT to*** * they **can't replace** that section of **primer**
158
What is **CHROMATIN?** * what's an example of something **made** **of** chromatin?
* general term for **"DNA+protein"** **CHROMOSOMES** are made of chromatin DNA+Histones
159
Cell Cycle: interphase
entire period OUTSIDE of mitosis
160
Lytic (cycle of) viral reproduction
-period during which viral genes are actively being transcribed and new viruses are being assembled. -During this phase, infected cells BURST!! to release large #'s of new viruses
161
G protein cascade: GDP is bound when protein is \_\_\_GTP is bound when protein is \_\_\_
GDP--offGTP--on
162
is rRNA an enzyme?
Not by itself, but when it assembles into a ribosome it can
163
Where are all of the places **Microtubules** could be found? HINT: Where there's **Cilia**, there are MT's (^^Theres a few **other** places you'd find MT's too^^)
* _The 3 places **cilia** are_ 1. lungs 2. ependymal cells 3. uterine cells * In the **flagella** of sperm * In **ALL** cells * as part of the **cytoskeleton** & **spindle apparatus**
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What are **Flagella?** * What are they used for? * What are the **ONLY** cells that have flagella?
**Flagella**: * whip-like projections from the cell body * used for **locomotion** * Human **sperm cells** are the only cells that have flagella
165
When is the only time chromosome number changes? (2)
1)during meiosis2) after fusion of gametes in the production of a zygote
166
G protein cascade * **G protein** is made up of what 3 subunits?
**α** **β** **γ**
167
Making genetic predictions for Dihybrid crosses--in the SAME individual
-Draw out 2 punnett squares (one for each trait) -To calc probability of 2 traits in the same individual, multiply the individual probabilities of each trait
168
rRNA
(ribosomal RNA)is the polymer of which ribosomes are constructed
169
Gene regulation * Describe **Activators** & **Repressors** Give an example of both, using the **Lac Operon** as a scenario
_Regulatory molecules can either:_ 1) **UPregulate** DNA transcription * ex: **lactose** in the lac operon 2) **DOWNregulate** transcription * ex: **glucose** in lac operon
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Major purpose of chromosomes is to...?
efficiently package the SUPER LONG DNA strands, so they can easily be stored b/t divisions and moved during division
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Cell Cycle: G0
-cells that enter this phase become non proliferative-basically, there arent actively dividing (and may not in the future)-Many full-differentiated Eukaryotic NEURONS remain in this phase indefinitely
173
What stage? Mitosis or meiosis? I or II?Tetrads line up IN PAIRS at metaphase plate
metaphase of meiosis I
174
endocytosis
where a cell takes up small particles by lumping into the plasma membrane, forming a vesicle called an endosome
175
Second messenger systems
-water-soluble hormones or signaling molecules bind to mem receptors on external surface of plasma membrane-this binding rarely stimulates immediate response from cell--more often it initiates a cascade that increases size of signal, which eventually stimulates cellular response
176
What would happen if crossing over didn't occur?
All of the genes on one chromosome would always demonstrate linkageLOSS OF GENETIC VARIATION! WHICH IS BAD!
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name the 3 components of NT's
1) triphosphate2) sugar3) base (one of four: ATCG)
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Northern Blot
for RNA sequences
179
Prokaryotes vs Eukaryotes differences
Pro: have no nucleus, no membrane-bound organelles, they have circular DNA, no histones or chromosome struc, and 70S(50S & 30S) ribosomesEuk: have a nucleus, mem-bound organelles, linear DNA with histones \* chromosome struc, and 80S(60S and 40S) ribosomes
181
Genes are regulated via 3 basic mechanisms. name them.
1) rate of transcription2) Activators and repressors3) permanent or semi-permanent suppression
182
If a male with a sex-linked recessive disease has children with a normal woman, ?
All of his daughters (XX) will be carriers
183
Adenine (A), pairs with?
T via 2 hydrogen bonds
185
\_\_\_\_\_\_\_\_s are a very common second messenger system that the MCAT loves to question you on
G-proteins!
186
Gram Positive vs Gram Negative: describe gram (+)
Gram Positive: -stain purple-very thick cell wall-form endosomes-Single cell membrane
187
In humans, **cilia** are found **exclusively** in what 3 **SYSTEMS?**
1. **Respiratory** system * lungs 2. **Nervous** system * ependymal cells 3. **Reproductive** system * uterine tubes
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Golgi Apparatus * What are its 3 main jobs?
* **Organize** proteins * **Continue** post-translational modification * _**Excrete** proteins in vesicles bound for:_ * Plasma membrane * organelles, or * **BACK** to the ER (retrograde transport)
189
Types of membrane transport (4)
1) simple diffusion: no ATP req'd2) facilitated diffusion: No ATP req'd (ex: osmosis)3) active transport: ATP req'd4) Secondary active transport: no DIRECT coupling of ATP req'd
190
Anaerobic respiration occurs mostly in?
Prokaryotes
191
* Mitosis * Anaphase
Anaphase is indicated by: * **separation of the chromosomes** and * **migration** toward the **opposite poles** of the cell
193
Compare metaphase for meiosis I and metaphase
meiosis I: tetrads line up IN PAIRS at the metaphase platemitosis: tetrads line up SINGLE-FILE at metaphase plate
195
Cell Communication: Juxtacrine
signaling req's direct contact b/t two cells
196
Crossing over happens to such an extent that two genes must...?
be VERY close to e/o on the chromosome to NOT assort independently (aka linkage...which is bad)
197
Differentiate b/t aerobic & anaerobic respiration
aerobic uses oxygenanaerobic doesnt use oxygen--DOES use an ETC, but doesnt use O2 as the e' acceptors
198
Connective tissue
bone, cartilage, blood, lymphatic tissue, fat, etc. basically, if a cell is obviously not epithelial, nervous, or muscle, it's probably connective
200
Mycorrhizae: symbiosis b/t what?
b/t fungi and plant roots
202
What happens to cholesterol in the cell membrane at higher temperatues?
non-polar region of CHO interacts with hydrophobic tails of lipids, holding them in place and this adding RIGIDITY
203
G protein cascade: what causes conformational change that activates cytosolic domain of an integral protein?
when a hormone or signal molecule binds to the GPCR
204
Cell Cycle: S phase
DNA replicated here
205
Mendel's Laws: Law of Independent association
genes located on different chromosomes assort independently
206
Function of glomerulus
capillary bed that strains the blood-allows fluids, ions, & molecules around the size of GLUCOSE (or smaller) to pass through Bowman's capsule-anything bigger will remain in the capillaries and exit via the efferent arteriole, which eventually empties into the renal vein
208
**ALL** proteins bound for cytosol plus **SOME** proteins bound for **other organelles** *are **made** on ?*
Free-floating **RIBOSOMES** in the **cytosol**
209
haploid cell has __ chromosomes
n for humans, n=23
211
Southern Blot
verify presence of DNA sequencesalso indicates relative size of restriction fragments
213
* Explain the **GRADIENT** across inner mitochondrial membrane * What happens if you were to insert **H+ channel**s within the membrane?
intermembrane space has **higher hydrogen ion [H+]** concentration, so it is **more** acidic * adding H+ channels would give H+ ions an **ALTERNATE** pathway back into the matrix **OTHER** than going **solely** via the ATP synthase * as a consequence, ATP production would **decrease**
215
p^2+2pq+q^2=1p+q=1What do p, q, p^2, and q^2 represent?
p & q refer to % of each ALLELE present as a fraction of all the alleles in the population-p^2 represents fraction of INDIVIDUALS who have homozygous dominant genotype (TT)-q^2 represents faction of individuals with the heterozygous genotype (tt) \*\*\*in short: p and q represent fractions of p and q ALLELES in the population\*\*\*q^2, 2pq, and q^2 represent fractions of INDIVIDUALS with each possible genotype
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What cellular junction is the STRONGEST of the four?Where might you find this type, and why?
Desmosomesfound in tissues that receive high amounts of shear stress, like the epidermis
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DNA replication: RNase H
removes all RNA primers
218
Cytosine (C), pairs with?
G via 3 hydrogen bonds
219
Semi-conservative (DNA rep)?
refers to fact that each of newly formed daughter helices is made up of one OLD strand plus one NEW strand
220
Bacteriophages
viruses that infect bacteria-have a capsid head, tail, tail fibers, etc.(typical virus looking thingy!)
221
Many enzymes are activated by?
Phosphorylation!
222
Genetics: How to make predictions. What should you always do FIRST?
Draw a punnett square
223
Where are steroid membrane receptors located? Why?
in the nucleusbecause steroids can diffuse through the hydrophobic membrane core (dont need a transport protein)
224
"-tase" means it is?
an ATP-requiring enzyme!!!
226
Vaccine definition & why do vaccines become less effective with time?
-is an inactive portion of a virus delivered to a person so their immune system can develop antibodies against the virus, without actually being infected by it-they become less effective b/c of SUPER FAST viral mutations!
227
Thymine (T), pairs with?
A via 2 hydrogen bonds
228
Function of proximal convoluted tubule (PCT)
-section of nephron b/t bowman's capsule & descending limb of the loop of henle-along PCT Na+ is reabsorbed via active transport & glucose is reabsorbed via secondary active transport-since water and solutes are reabsorbed in the same ratio, the filtrate remains ISOTONIC
229
Cell Cycle: G2
comes after S. -cell continues to grow & has high metabolic activity (esp. production of microtubules in preparation for mitosis)
230
Taxonomy"Do Kings Play Chess On Fridays, Generally Speaking?
DomainKingdomPhylumClassOrderFamilyGenusSpecies
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What will you assume if you're asked to predict the genotype of offspring when you are NOT given info on ONE of the parents?
assume the other parent is NOT affected, thus NOT a carrier of whatever
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**MYOSIN** is a \_\_\_, not a \_\_\_
**MOTOR PROTEIN** **NOT** a microfilament!!
234
Cell Communication: Autocrine
signal molecules secreted by a cell bind to receptors ON THAT SAME CELL
235
"The Species Distinction"
organisms classified as different species should not be able to mate with one another and produce viable, fertile offspring
236
What is the **9+2 format**?
* **NINE** doublets (**2** microtubules each) surrounding a **CENTER** doublet (**2** microtubules) in a **wheel-like** design ***Total of 20 microtubules** (18+2)* * **Each** of **these** microtubules are made up of **13** protofilaments
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What are some things that trigger cell apoptosis? (4)What's something else apoptosis does apart from removing bad cells?
extreme heatradiationviral infectionDNA damage, etcCan also remove healthy, but unwanted cells
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Gram Positive vs Gram negative: describe gram (-)
-stain pink-relatively thin cell wall-do NOT form endosomes-contain 2 cell membranes: one inside the cell wall and one outside the cell wall
241
exocytosis
vesicle on inside of membrane fuses with plasma membrane & dumps its contents into extracellular space
242
Define: **Thin filaments** of the sarcomere
* Formed from **microfilaments** ## Footnote *Thin filaments act as a **TRACK** along which **THICK** **FILAMENTS** move during contraction*
244
Making genetic predictions for dihybrid crosses-- "for __ # of individuals" w/ a phenotype or genotype
-If # of individuals with a specific genotype or phenotype is asked for, multiply the total probability of having BOTH traits by the total number of offspring
245
Meiosis Yields:
4 genetically distinct HAPLOID daughter cellsCentromeres do NOT split during meiosis I, but do during meiosis II
247
Cell Communication: Paracrine (plus example)
signal molecules secreted by one cell bind to receptors on other cells in the local area. ex: neurotransmitters acting in the synaptic gap
248
How many chromosomes in a haploid cell?
23
249
Molecular cloning: gel electrophoresis
lab technique used to separate molecules by size
250
Gene Regualtion: permanent or semi-permanent suppression
Methylation or other covalent modification that prevents or dramatically DECREASES transcription
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What are **Thick filaments** made of? **What** do they move along, and **during** what?
* Made up of **MYOSIN** (**motor proteins)** * move along **thin filaments** * during **contraction**
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Lysogenic (cycle of) viral reproductionexample?
-is the dormant cycle of the virus during which time viral DNA is incorporated into the host's genome, but new viruses are not being assembled. ex: HIV infection without having AIDS symptoms
253
Chemotrophs
oxidize organic or inorganic cpds to harvest energy
254
Phases of Mitosis: prophase
nuclear membrane dissolves and chromosomes condense
255
Do mitochondria use the same genetic code to translate their DNA?
NOPE
256
Genetics: what is assumed for an individual with the DOMINANT phenotype?
Homozygous dominant
257
Anaerobic respiration takes place where? (2)
Cytoplasm & mitochondria
258
Do all human traits follow the Mendelian pattern?
NOPE! Most dont, actually.
259
"Wild Type" =?
the normal or typical phenotype
260
Mitosis yields
2 genetically IDENTICAL diploid daughter cells, which are genetically IDENTICAL to the mother cell that produced them\*The centromeres split\*
261
histones
proteins around which DNA helix is wrapped when condensed into chromosomes
262
DNA replication: DNA polymerase reads in _____ direction, thus builds new strands in the ___ direction
3' to 5' builds new strands in 5' to 3' direction
264
DNA replication is: (3) name the traits
bi-directionalsemi-conservativesemi-discontinuous
265
"-ase" means it is ?
an enzyme
266
Guanine (G), pairs with?
C via 3 hydrogen bonds
267
DNA replication: What does the primase (which is an \_\_\_) do?
(which is an RNA polymerase)constructs short RNA primers on both strands
268
Mutualism
form of symbiosis where both parties benefit equally
269
nucleosomes
set of 8 histone proteins in a cube shape with DNA coiled around it.
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**Microfilaments** are made up of ___ subunits
**actin subunits**
271
Genetic probabilities: "BOTH/AND"
if both events occur simultaneously, multiply probabilities of each event occurring individually
272
What besides DNA and RNA are nucleotides present in?
Telomerase & ribosomes have bits of attached RNAATP has NT's too
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# Define: Surface ("Peripheral") proteins * Where are they **ENTIRELY** contained/found?
* Proteins **on** a cell membrane that **DONT** **enter into hydrophobic core*** * contained entirely on **polar** surface of membrane
274
Genetic Regulation **LAC OPERON:** _How much_ synthesis of *lac* mRNA can you expect if: * You have **BOTH** lactose (activator) **AND** glucose (repressor) present
* Since Glucose **IS** present, you'll have **low cAMP*** * cAMP **unable** to bind & activate CAP, which is **unable** to help RNA Poly bind to the **Promoter** region* Since RNA Poly is **LESS LIKELY** to bind to promoter region: * you'll have **VERY LITTLE** *lac* mRNA synthesized
275
Genetic Regulation **LAC OPERON:** _How much_ synthesis of lac mRNA can you expect if: * Lactose (activator) is **PRESENT**, and Glucose (Repressor) is **SCARCE?** **EXPLAIN WHY!**
* Since glucose is **SCARCE**,* * cAMP **IS** able to bind to CAP* * This enables RNA Poly to **easily bind** to the **PROMOTER** region **=HIGH LEVELS of *lac*-mRNA synthesis**
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**MEIOSIS I** * Takes a cell with __ pairs of **\_\_\_\_\_\_\_\_\_** chromosomes (or __ **total** chromosomes) * ...and **creates** _ \_\_\_\_ * **Each** with __ non-\_\_\_\_\_ed, non-\_\_\_\_\_\_\_\_\_ chromosomes
**MEIOSIS I** * Takes a cell with **23** pairs of homologous chromosomes, or **46** total chromosomes * and creates **two** cells * each with **23** non-**paired**, non-**homologous** chromosomes
277
Generally speaking, **chromosomes** tend to ______ in size throughout the cell cycle _Example_: In **Meiosis I**, You **start** with 23 homologous chromosomes * Which of those 23 chromosomes will be the **LARGEST?**
***DECREASE!*** **1 \>\>\> 23** *Chromosome **ONE** is **BY FAR** the **LARGEST** chromosome! (Always!)*
278
During cell division, are chromosomes **DUPLICATED?** * How do levels of **DNA** and **Chromosomes** vary during cell division?
* Chromosomes are **NEVER**"duplicated"* * in number during cell division* _They are “**REPLICATED**”_ * meaning **each** single chromosome gains an **identical** sister chromatid * ...but **only** the amount of **DNA** has **INCREASED*** * ...the # of chromosomes has **NOT!!!*** * **Before** DNA replication each cell will have **46** chromosomes * Afterward each cell will **still** have **ONLY** **46** chromosomes
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*Which of the following statements is/are **TRUE** regarding human chromosomes?* I. In their **condensed** form they contain a large amount of **protein** II. They are in their **condensed** form for the **majority** of the cell cycle III. They contain **nucleosomes** IV. There are 46 non-identical chromosomes in each **somatic** cell * **A**. II and IV * **B**. I and III * **C**. I, II and III * **D**. I, III and I
**D** ## Footnote _Statement I is true_ * Chromosomes contain many **histones** * **​**which are a type of **protein** _Statement II is false_ * During most of the cell cycle the chromosomes are **unwound** * Not until **prophase** do the chromosomes condense _Statement III is also true_ * A nucleosome is a **set of four histones** wound together _Statement IV is true_ * You may be tempted here to think that we only have 23 pairs of non-identical chromosomes because of the existence of homologues * That would be true **IF** homologues were **identical** * However, homologues are definitely non-identical because they contain a random assortment of alleles
280
What is a **PROTEIN** that is **very abundant** in **CHROMOSOMES?** * *HINT: Chromosomes package DNA.....*
***HISTONES!***
281
During most of the cell cycle, **CHROMOSOMES** are **wound/unwound?** * It's not until _____ that the chromosomes \_\_\_\_\_
* During most of the cell cycle,* * chromosomes are **UNWOUND*** Not until **PROPHASE** do the chromosomes **CONDENSE**
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# Define a **NUCLEOSOME** * Where could you find them?
a nucleosome is a set of four histones wound together * Found in **CHROMOSOMES!** ​*_REMEMBER_:* * Chromosomes package **DNA*** * Where there's **DNA**, there **Histones**, & where there's Histones there's **Nucleosomes***
283
There are **ALWAYS** __ chromosomes in a somatic cell **before**, **during**, and **after** MITOSIS
**46!!!**
284
***Uptake** of glucose from the gut and **transport** of K+ ions through the voltage-gated channels of a neuron are best described as:* * A. secondary active transport and active transport, respectively * B. active transport and facilitated diffusion, respectively * C. secondary active transport and facilitated diffusion, respectively * D. active transport and diffusion, respectively
**C** ## Footnote Uptake of glucose at both the gut and the kidney is accomplished via a **secondary** active transport system-- Meaning that a “secondary” molecule is **actually** the one **actively** transported * in order to get the molecule of interest **into** or **out of** the cell In this case, sodium is transported **against** its gradient * where it **pairs** **with glucose** * and brings it **back** into the cell * back **down** sodium’s gradient The flow of K+ ions thru a potassium channel in the neuron does **NOT** involve ATP, * and is thus **REGULAR** diffusion * However, because it goes **thru** a **CHANNEL PROTEIN**, it is considered “**facilitated** **diffusion**”*
285
*Which of the following is **NOT** a function of the **endoplasmic reticulum?*** * A. **detoxification** of cellular chemicals * B. lipid **production** and **metabolism** * C. synthesis site of **extracellular** proteins * D. post-translational modification of proteins
**B** ## Footnote _The ER, between the smooth and rough sections, is responsible for:_ * **Detoxifying** chemicals * **producing** lipids * **synthesizing** extracellular proteins * **modifying** translated proteins * and various other functions *The key here is that lipids are* ***MADE** at the smooth ER...* ...but are **METABOLIZED** in the **MITOCHONDRIAL MATRIX!!!** Thus B is a false statement and is the correct answer
286
**DESMOSOMES** are found in tissues that receive a lot of ____ and \_\_\_\_, such as _______ cells *REMEMBER: Desmosomes are the **strongest** of the 4 cell junction types*
Desmosomes are found in tissues that receive a lot of **PRESSURE** and **IMPACT** * such as **epithelial** **cells**
287
Describe **SUBSTRATE-LEVEL PHOSPHORYLATION** * Where's one place this happens?
**_Substrate-level phosphorylation_** is a type of metabolic reaction that results in the formation of ATP or GTP by: * the **DIRECT** **TRANSFER** of a **PHOSPHORYL GROUP**(PO3) * ....to ADP or GDP * from a phosphorylated reactive **intermediate** * This happens in the KREBS CYCLE!* * GDP is phosphorylated into GTP*
288
What is it that **INTRONS** are spliced *out of?*
Introns are removed from **pre-mRNA** | (**NOT** replicated DNA!)
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* The DNA strand shown below is from the **CODING (!) strand** of a section of human DNA* * Which of the following gives the matching **pre-mRNA** sequence?* **5’ATTCG3’** * A. 5’UAAGC3’ * B. 3’UAAGC5’ * C. 3’GCUUA5’ * D. 3’AUUCG5’
**C** 5’ATTCG3’ 3’GCUUA5’ * To answer this correctly, you must differentiate **“coding strand”** from **“template strand.”** The template strand is the one **copied** The coding strand is the other strand * the **complement** to the template strand * which is **NOT** copied As a result, the: * new **DNA** strand OR * the new **pre-mRNA** strand * will be an **EXACT COPY** of the **coding** strand* * (EXCEPT, in the case of pre-mRNA, T will be replaced with U)* * The next skill you need is to keep careful track of the 3’ and 5’ ends * Normally, we need the strands to run in **opposite** directions * (so if the template strand was listed 5’ to 3’ the new strand would consist of the matching base pairs running 3’ to 5’) ***However**, note that here you are **NOT** given the **template** strand, but the **coding** strand* Thus, the **coding** strand and the **new pre-mRNA** strand will both run the **same** direction and will be **identical** * except for replacing T with U
290
**IMPORTANT!** * **GENES** can only produce *WHAT?* * You cannot have a gene transcribed, and then translated into a \_\_\_\_\_, a \_\_\_, or anything else.
Genes can **ONLY** produce **PROTEINS!** ## Footnote DON’T FORGET THIS! * You **cannot** have a gene transcribed and then translated into a **carbohydrate**, a **fat**, or anything else
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*_HYPOTHETICALLY_:* **​Hormone Q**⇒ **Receptor P** ⇒activates **adenyl cyclase** ⇒converts **ATP** to **cAMP** ⇒leads to **phosporylation** of **Protein Z,** *which actively transports Glucose into cell* \*\*\* If you needed to **QUICKLY** remove Glucose from the cell, inhibiting which of the above things would do it **FASTEST?** Why?
**DEPHOSPHORYLATING** **PROTEIN Z** * Stopping the final step in the chain * In this case, it will **not** matter what **previous** molecules are still present *If you were to remove all of Hormone Q, for example, you'd still have to **wait** for whatever was there right **BEFORE** removing it to **make its way through the cascade***
292
**LYSOGENIC vs. LYTIC** Which is the "DORMANT" cycle? Will it always be dormant?
**LYSOGENIC=DORMANT** * It is **inevitable** that at some future time, usually during a time of **stress**, the virus **WILL** become “lytic” * and commandeer the host’s machinery to actively produce **virions**
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**FUNGI** * They have cell walls containing \_\_\_\_\_ * They are _____ during most of their life cycle * They ____ food before \_\_\_\_\_ing it * They are capable of both _____ and _____ reproduction
* They have cell walls containing **CHITIN** * They are **HAPLOID** during most of their life cycle * They **DIGEST** food before **INGEST**ing it * They are capable of both **SEXUAL** and **ASEXUAL** reproduction

ALTIUS (27 decks)

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