Biology 1 Flashcards
The intermembrane space has a ___er pH than the matrix
- Therefore, the intermembrane space is more ____
lower pH than matrix
intermembrane space is more acidic
Tissue organization: ___>___>___>___
Organ systems>Organs>Tissues>Cells
Tetrads line up SINGLE-FILE at metaphase plate
Metaphase of Mitosis
Key word: “Single File”
What are the 3 main functions of PEROXISOMES?
- Self-replicate
- Detoxify chemicals
- Participate in lipid METABOLISM
- along with mitochondria
What are the 2 HARDY-WEINBERG Formulas we need to know?
p2+2pq+q2=1
p+q=1
- Mitosis
- Prophase
During prophase:
- the nuclear membrane dissolves
- the chromosomes condense
- Mitosis
- Telophase
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
What are Heterotrophs?
- UNABLE to fix CO2 (like autotrophs can)
Therefore, heterotrophs must INGEST organic molecules (such as carbohydrates) as their carbon source
Non-nuclear DNA is found where?
mitochondria
What are 4 characteristics about the NUCLEUS?
- Where DNA is
- DNA cannot leave nuleus
- Is by a dual bi-layer membrane
- one bi layer is continuous with ER
- contains nuclear pores
DNA replication
- Describe DNA ligase
Creates the LAST necessary PHOSPHODIESTER bond to the downstream neighbor
thus creating a COMPLETED strand! Yayyy!!!
What is the Endosymbiotic Theory?
- suggests mitochondria evolved from aerobic PROkaryotes
- …that were engulfed by an ancient EUKaryotic cell (common ancestor)
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)
Results from:
- Errors during replication, or
- Methylation of guanine
ex: one form of methylated guanine pairs with thymine INSTEAD of cytosine…whoopsy daisy
Define a Membrane receptor
any protein that specifically binds to a signaling molecule (ligand)
- …and initiates a cellular response
- In order for natural selection to occur, what 2 things must happen?
HINT: Polymorphisms (discontinuous genetic variation)
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
GLIAL CELLS, such as:
- Astrocytes
- Schwann cells
- Oligodendrocytes
- Ependymal cells
are also considered to be what?
- Also! Remember that EPENDYMAL cells contain…?
NERVOUS tissue
EPENDYMAL cells contain CILIA!
DNA replication: sliding clamp
protein that keeps DNA poly tightly bound to strand
How does reproduction work in Prokaryotes (Bacteria)?
- How does the distribution of DNA work?
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
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….
- is for PROTEIN segments
- instead of NT segments
-
Radioactive antibodies are used as probes
- instead of NT sequences being used as probes
What is PINOCYTOSIS?
invagination of:
- extracellular fluid
- very small particles
occurs in ALL cells
Define: Actin
a protein monomer that polymerizes to form MICROFILAMENTS
How does mRNA interact with DNA?
is the complementary RNA strand
…COPIED FROM the DNA template strand
- What are the 6 possible destinations for ALL proteins?
- Where are all these proteins made?
- ER
- Golgi
- Lysosomes
- Endosomes
- Plasma Membrane
- Extracellular secretion
made in: RER
How many layers must you go through to get from outside of the cell to the nucleus?
6 total
- 2 for cell membrane
- 2 for outer nuclear membrane
- 2 for inner nuclear membrane
Fungi have cell ___ made of ___
cell walls made of chitin
What are Integral proteins?
- What is its opposite?
Proteins that have one or more segments embedded within each phospholipid bilayer
- opposite=surface/peripheral proteins
What 2 things exhibit the 9+2 arrangement?
Eukaryotic:
Cilia & flagella
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
Chromosomes generally _____in size, with ______ being by far the largest
generally DECREASE in size, with chromosome One being by far the largest
The Cytoskeleton consists of?
- Microtubules
- Intermediate Filaments (IMF’s)
- Microfilaments
In gene regulation, regulatory molecules are often what 3 things?
Regulatory molecules are often:
- Hormones
- Upstream products of rxn or cascade that is catalyzed by gene product
- Byproducts that build up when the [] of the gene product is low
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
How many protofilaments surrounding a hollow core make up a microtubule?
13
What are Adherens junctions?
STRONG, MECHANICAL
attachments b/t cells
- Meiosis I
- Interphase I
Post-translational modification:
- usually occurs at?
- what are some common modifications?
- Occurs at:
- ER and the Golgi
Includes ADDITION of:
- polysaccharides
- lipids, or
- phosphates
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
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
- cell surface
Name Mendel’s Laws (2)
- Law of…
- Law of Segregation
- Law of Independent Assortment
What is Bidirectional (DNA replication)?
- Refers to fact that DNA replication proceeds in both directions (5→3, 3→5) simultaneously
- Starting from the origin
Lysosomes
- Have a pH of what?
- What are the 3 main functions of Lysosomes?
- pH of 5
Functions:
- Digest cell parts
- Fuse with phagocytotic vesicles
- participate in apoptosis
- Mitosis
- Metaphase
Metaphase is indicated by:
- the chromosomes lining up at the metaphase plate and
- formation of the spindle apparatus
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
Genetics:
- An individual having two different alleles of a particular gene or genes
- and so giving rise to varying offspring
Would be a…?
HETEROzygote
____ is ALWAYS req’d to move something against its [] gradient or against an electrical potential
active transport
Describe:
HypOtonic solutions
LESS concentrated than the cell
- driving water to ENTER the cell
- it might BURST!
water⇒cell
Cellular Junctions
- Describe TIGHT Junctions
are water-proof barriers
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!
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
The NUCLEOLUS is the site of what 2 things?
Nucleolus= Nucleus WITHIN the Nucleus!
Nucleinception
NUCLEOLUS:
Site of:
- rRNA TRANSCRIPTION
- Ribosome assembly
Mechanisms of DNA Repair:
- Describe Proofreading
- DNA polymerase catches and repairs most mismatched base pairs…
RIGHT AS IT HAPPENS!
Phases of Mitosis:
- What phase is it if you see:
- a single cell
- with a well-defined nuclear membrane and
- uncoiled chromosomes?
INTERPHASE
Lipids are made/ synthesized in the _____,
but metabolized in the _____
- made in SER
- metabolized in the mitochondria
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
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
DNA is a polymer of WHAT?
DEOXYRIBOSE nucleotides
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
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
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
Describe the 4 steps of PCR
- What does HEATING the DNA do?
- Where do you add Taq Polymerase?
- What does COOLING the mixture do?
-
Heat DNA
- denatures helix
-
Add primers
- using Taq polymerase
-
Cool mixture
- this anneals (recombines) primers
- Heat again
Polymerase then copies DNA
- making 2 new DNA helices
- repeat many times over*
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
The Smooth ER is the site of?
Site of lipid synthesis/modification
(but NOT the site of lipid metabolism!)
DNA replication:
- What do Single-Stranded Binding Proteins (SSBP’s) do? 2 things
- COAT the individual strands
- PREVENT them from re-annealing (unwinding)
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
- RNA or DNA
- Plus PROTEINS
- 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
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*
Name the 4 types of Cellular Junctions?
- Tight Junctions
- Gap junctions
- Adherens junctions
- Desmosomes
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
Apoptosis
programmed cell death, courtesy of lysosomes
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
How are PHOSPHOLIPIDS formed?
- What 3 things do you COMBINE?
1 GLYCEROL
+
2 FA’s
+
1 PO42-
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
Genetics:
- An individual who carries two identical copies of the recessive gene is…?
HOMOzygous RECESSIVE
tRNA
is the molecule that bridges gap b/t mature mRNA and assembled protein
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
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
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
How many chromosomes do humans have…during interphase
46
DNA polymerase can only add to an existing ______ group
3’ OH group
Commensalism
form of symbiosis in which one participant benefits and the other’s experience is neutral (not good, not bad. It’s whatevs)
Human taxonomy”All Cool Men Prefer Having Heavy Sideburns”
AnimaliaChordataMammaliaPrimatesHominidaeHomo Sapiens
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
Define: Phospholipids
- lipid molecules with a non-polar tail*
- and a polar phosphate head*
- Make up a bilayer of a cell membrane
Basic structure of bacteria
Capsule, peptidoglycan cell wall, plasma membrane, no complex-bound organelles, single circular DNA chromosome, tiny circular DNA molecules called plasmids
Phototrophs
can capture their own energy directly from the sun via photosynthesis
Kinetochore
specialized group of proteins to which spindle fibers attach during mitosis/meiosisoften, kinetochore is used synonymously with “centromere”
Define: ampiphatic
when a molecule has both polar and non polar regions (like a lipid bilayer)
Homologues are?
two related, but non-identical chromosomes–one originating from EACH parent
How many chromosomes in a diploid cell?
46
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
What does “quiescent” mean? What’s an example of this?
Means stable, not changing, & unlikely to changeex: G0 phase of cell cycle
Aerobic respiration reactants (2) & products (3)
reactants: glucose & oxygenproducts: CO2, water, ATP
Anaerobic respiration reactants & products
Reacs: Glucose, electron acceptor (anything BUT oxygen)Products: CO2, whatever “thing” (which gets reduced), and ATP
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
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
Bacteria reproduce via ?
Binary fission
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
Bacilli are ___ shaped bacteriaCocci are ___ shaped bacteriaSpirilla are ___ shaped bacteria
rodsphericalspiral
What is Tubulin?
- a globular protein that polymerizes to form MICROTUBULES
Aerobic leads to complete ____ of respiratory materialproduces ___ ATP per ___
complete oxidation of respiratory materialproduces 38 ATP per glucose
Origin of replication
is the location on the chromosome where replication begins
What fills the gaps made when RNase H removes the RNA primers?
DNA polymerase
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
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
Centromere
region of the chromosome that joins the sister chromatids
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
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
Name the 3 causes of DNA damage
1) Spontaneous hydrolysis2) Damage by external chemicals or radiation3) mismatched Base pairs
TelomerASE is?
an enzyme that adds length to the telomeres
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
When (at what phase of what) does crossing-over occur?
occurs during prophase of meiosis I
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
What role does cholesterol play?
Adds rigidity and fluidity to the membrane
Define: Intermediate Filaments (IMFs)
Several proteins that polymerize to form filaments that are:
-
INTERMEDIATE in diameter b/t:
- microfilaments (smallest)
- microtubules (largest)
Diploid cell has __ chromosomes
2n
G protein cascade: What activates protein kinase A (PKA)?What does PKA do?
-cAMP-PKA phosphorylates proteins, usually enzymesBOOM! Cascades
Remember that all bacteria are ______
prokaryotes
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
DNA replication: What is the helicase?
it unzips the double-helix