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Bio
Memorize:
● Sucrose - glucose + fructose disaccharide.
● Lactose - galactose + glucose disaccharide.
● Maltose - glucose + glucose disaccharide.
Polysaccharides contain many monosaccharides
connected by glycosidic bonds into a long polymer.
Memorize:
● Starch - energy storage for plants and is an
alpha (α) bonded polysaccharide. Linear
starch is called amylose , while the branched
form is amylopectin .
● Glycogen - energy storage for humans and is
an alpha (α) bonded polysaccharide. Much
more branching than starch.
Cellulose - structural component in plant cell
walls, and is a beta (β) bonded polysaccharide.
Linear strands packed rigidly in parallel.
● Chitin - structural component in fungi cell walls
and insect exoskeletons. It is a beta (β)
bonded polysaccharide with nitrogen added
enzyme
The induced fit theory describes how the
active site molds itself and changes shape to fit
the substrate when it binds. The outdated
theory was the “lock and key” model .
● A ribozyme is an RNA molecule that can act
as an enzyme (a non -protein enzyme).
Competitive inhibition → K M increases, while V max
stays the same
Noncompetitive inhibition → K M stays the same,
while V max decreases
lipids
Factors that influence membrane fluidity:
1. Temperature - ↑ temperatures increase fluidity
while ↓ temperatures decrease it.
2. Cholesterol - holds membrane together at
high temperatures and keeps membrane fluid
at low temperatures.
3. Degrees of unsaturation - saturated fatty
acids pack more tightly than unsaturated fatty
acids, which have double bonds that may
introduce kinks .
A phospholipid is termed an amphipathic molecule because it has
both polar (hydrophilic) and nonpolar (hydrophobic) regions.
Steroids are characterized by a backbone of four linked carbon ringsand are amphipthic
Like phospholipids,
integral proteins are amphipathic, with the hydrophobic regions embedded in the
membrane and the hydrophilic regions
exposed to the aqueous solutions bordering the membrane.
Recognition
proteins are glycoproteins because they have short polysaccharide chains
(oligosaccharides) attached.
Ribosome subunits are manufactured in the nucleus and consist of RNA molecules and
proteins. The two subunits,
labeled 60S and 40S, move across the nuclear envelope and into the cytoplasm where
they are assembled into a single
80S ribosome.
Lysosomes are vesicles from a Golgi apparatus that contain digestive enzymes.
Lysosomes do not occur in plant cells.
In liver cells, smooth ER is involved in the breakdown of toxins, drugs, and toxic byproducts
from cellular reactions.
Peroxisomes are common in liver and kidney cells where they break down toxic
substances.
flagella and cilia consist of microtubules arranged in a “9 + 2” array—nine pairs
(doublets) of microtubules
arranged in a circle surrounding a pair of microtubules
Both centrioles and basal bodies are made up of nine triplets of microtubules arranged in
a circle
Plant cells lack centrioles
Cell walls are found in plants, fungi, protists, and bacteria. The extracellular matrix is
found in animals, in the area between adjacent cells
Note that plant cells can generally be distinguished from animal cells by the
following:
1. the presence of cell walls, chloroplasts, and central vacuoles in plant cells and
their absence in animals
2. the presence of lysosomes, centrioles, and cholesterol in animal cells and their
absence in plants
bacteria are prokaryotes and lack all the organelles described above.
They generally consist of only a plasma membrane, a DNA molecule, ribosomes, cytoplasm, and often a
cell wall.
Prokaryotic ribosomes are smaller (70S, with 50S and 30S subunits) than those of eukaryotes (80S, with
60S and
40S subunits).
ECM- Integrin - transmembrane protein that
facilitates ECM adhesion and signals to cells
how to respond to the extracellular
environment (growth, apoptosis, etc.).
Cellular resp ETC - NADH provides electrons that
have enough energy to generate about 3 ATP, while FADH2 generates about 2 ATP.
Photosynthese
C4 photosynthesis provides two advantages: It minimizes photorespiration and reduces water loss. C 4
photosynthesis
occurs in about a dozen plant families. Sugarcane, corn, and crab grass are examples. C4 plants are found in
hot, dry climates,
in CAM, CO2 is temporally segregated. The advantage of CAM is that photosynthesis can proceed during
the day
while the stomata are closed, greatly reducing H2 O loss. As a result, CAM provides an adaptation for
plants that grow
in hot, dry environments with cool nights
Photosynthesis is non-spontaneous and
endergonic , producing glucose after an input of
solar energy.
Cellular respiration is spontaneous and exergonic ,
breaking down
Cell dividion
Centrioles replicate during the
S phase of the cell cycle so that each daughter cell
after cell division has one centrosome.
In animal cells , cytokinesis begins in late anaphase
with the formation of a cleavage furrow .
In plant cells , cytokinesis begins in telophase with
the formation of a cell plate .
binary fission is used by
archaea, bacteria, and certain organelles to
reproduce .
During binary fission , organisms will replicate
their genome while cell division is happening (no S
phase for DNA replication). Also, there is no spindle
apparatus .- In binary fission, the chromosome replicates
and the cell divides into two cells, each cell bearing one chromosome. The spindle apparatus, microtubules,
and centrioles
found in eukaryotic cell divisions are lacking, since in bacteria, there is no nucleus to divide.
dna replication
An origin of replication is required to initiate DNA
replication, where the DNA strands first separate.
Initiation - creating origins of replication at
A-T rich segments of DNA because A-T bonds
only have two hydrogen bonds.
protein sunthesis
The three steps in protein synthesis are transcription, RNA processing, and translation
there are 64 possible codons. However, there are only 20 amino acids, and thus, some codons
code for the same amino acid.
Note that three of the codons in the genetic code are stop codons (UAA,UGA,UAG). They signal an end
to translation rather than code for an amino acid. Therefore, only 61 of the codons actually code for amino
acids.
Ribosomes have three binding sites—
one for the mRNA, one for a tRNA that carries a growing polypeptide chain (P site, for “polypeptide”), and
one
for a second tRNA that delivers the next amino acid that will be inserted into the growing polypeptide
chain
(A site, for “amino acid”).
Transcription begins with initiation, continues with elongation, and ends with termination.
In the cytoplasm, amino acids attach to the 3' end of the tRNA’s, forming an aminoacyl -tRNA.
Energy for translation is provided by several GTP molecules.
A tRNA (with anticodon UAC) carrying the amino acid methionine attaches to the mRNA at the start
codon AUG.
Memorize these codons →
Start codon: AUG (methionine)
Stop codons: UAA , UAG , UGA (end translation, do
not code for any amino acid)
A mutation is any
sequence of nucleotides in a DNA molecule that does not exactly match the original DNA molecule from
which it was
copied. A point mutation is a single nucleotide error
frameshift mutation is the most detrimental- can change many amino acidios
DNA segments within a DNA molecule can move to new locations. These transposable genetic elements,
called
transposons (or jumping genes )
bacteria genetic variation
conjugation- F plasmid, contains the genes
that enable a bacterium to produce pili. When a recipient bacterium receives the F plasmid, it too can
become a
donor cell. A group of plasmids, called R plasmids, provide bacteria with resistance against antibiotics.
Virus
The capsid is a viral protein coat that is made of
subunits called capsomeres .
Heredity
genes for genotype and physical trait for phenotype
Domiance- To help you distinguish the three kinds of inheritance, imagine a continuum. At one extreme,
there is complete dominance
by a dominant allele over a recessive allele. At the other extreme, both alleles are expressed (codominance).
Between the
two extremes, a blending of two different alleles produces an intermediate phenotype (incomplete
dominance).
Commit these three single allele crosses to memory:
1.
2.
3.
Homozygous x homozygous = 1/1 AA or 1/1 Aa or 1/1 aa
Homozygous x heterozygous = ½ AA (or aa) and ½ Aa
Heterozygous x heterozygous = ¼ AA, ½ Aa, ¼ aa (Remember, this is our 1:2:1 ratio from a
monohybrid cross seen above)
F2 cross YyxYy  See diagram below for an example of a monohybrid cross. We can
see that for the F2 generation, the genotype ratio (YY:Yy:yy) should always be
(1:2:1). The phenotype ratio (dominant:recessive traits) should always be (3:1).
Dyhybrid cross
For this reason, we don’t need to memorize the genotype ratios since we can always draw the Punnett
Square out if we need to. However, to speed things up on the DAT, it might be helpful to remember that the
phenotype ratio (dominant : recessive traits) should always be (9:3:3:1).
9 is the phenotype with both dominant traits. (i.e., yellow and round peas)
3 is the phenotype with one recessive and one dominant traits. (i.e., green and round peas)
3 is the phenotype with also one recessive and one dominant traits, just the other way round. (i.e.,
wrinkled and yellow peas)
1 is the phenotype with both recessive traits. (i.e., green and wrinkled peas).
These single locus ratios will come in handy for probabilities of multi-locus crosses. The easiest way to
compute multi-locus crosses is to look at each of the loci individually—figure out the single gene
probabilities—and then multiply each single gene ratio to get the overall probability.
For example, say we were asked to determine the probability of producing an offspring with the following
genotype, Rryy, from two heterozygous parents, RrYy x RrYy:
If we break the genotype for these two parents up, we can create two single allele crosses:
We know that crossing two heterozygotes will produce ½ of offspring that are heterozygous and ¼ of
offspring that are homozygous recessive.
Therefore, the probability of producing an Rryy offspring from two RrYy parents is:
Linked genes
The greater the distance between two genes on a chromosome, the more places between the genes that the
chromosome
can break and thus the more likely the two genes will cross over during synapsis.
f two genes show a recombination frequency that is anything less than 50%, the genes are linked
de
It is very important to be able to understand and deduce genotypes from pedigree charts,
since it’s a high frequency test subject on the DAT. If you are asked about an individual,
don’t simply look at him/her, also take a look at his parents and/or offsprings to get more
clues. Follow a clear logic and you will be able to ace these types of questions!
https://www.youtube.com/watch?v=9IsUSaQqk5M
https://www.youtube.com/watch?v=1qYcK0bzXv4
https://www.youtube.com/watch?v=iPKY97pghAo
https://www.youtube.com/watch?v=3zXMAzcsF2M&ab_channel=DirtyMedicine
https://www.youtube.com/watch?v=kgRhwTmynI&ab_channel=Nikolay%27sGeneticsLessons
diversity of life
Domain- arcchae, bacteria, eukarya
Aechae mostly found in extreme environments – cand cause infection
animal kingdo m -Animalia:
Animals share several general features. These include the fact that animals are eukaryotic, diploid, and
multicellular. In addition, animals are heterotrophic aerobes meaning they cannot make their own food
(they must consume it), and they depend on oxygen.
Animals are usually motile at some point during their life, which also means that many have nervous and
muscular systems
.
Animalia
Do you have tissues?
NO= Porifers (sponges)
Do you have tissues ? YES = line below which type of symmetry
bilateral- do you have a coelom?
Coelomate which blastopore is formed first? Mouth(protosome) or anus(deuterosome)
-can never have identical twins
arthropoda = arachnids, insects, crustacean
plants
bryophyte= mosses and lichens like grass, no stems
dicots = trees
Two haploid gametes fuse producing diploid
zygote → zygote becomes sporophyte via mitosis
→ in their sporangia, sporophyte undergoes
meiosis to produce haploid spores → spore
becomes gametophyte via mitosis →
gametophyte produces gametes → cycle repeats.
Primary Structure of Stems
○ Similar to the root, except the casparian strip and endodermis are usually missing
(they are specialized for water absorption which only takes place in the root).
During seasons of growth, the vascular cambium actively divides. When
the seasons come to an end, the growth phase is halted. This alteration of
growth → dormancy → growth produces annual rings in the secondary
xylem tissue which can help us determine the age of the tree. The size of
the ring corresponds to the amount of water available during the year,
also allowing us to provide a history of the rainfall in that region.
DAT Mnemonic: inflammatory response → SLIPR:
Swelling
Loss of function
Increased heat
Pain
Redness
The primary agents of the immune response are lymphocytes, white blood cells (leukocytes) that originate
in the bone
marrow (like all blood cells) but concentrate in lymphatic tissues such as the lymph nodes, the thymus
gland, and the
spleen.
Respiratory system
circulatory
Open circulatory systems occur in insects
and most mollusks.
Closed circulatory systems are found among members of the phylum Annelida (earthworms, for example),
certain
mollusks (octopuses and squids), and vertebrates.
OAT TIPS
lactic acid fermentation
enzymes
myoglobin
Hemoglobin O2 affinity
finished at Ch 8 pg 139
ch 20