DAT Biology Actual test with
Questions and 100% Correct
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What makes up a glycolipid? - ✔✔Same as a phospholipid but with a carbohydrate instead of
phosphate group.
Why are lipoproteins required to transport lipids in the blood? - ✔✔They are insoluble.
What increases membrane fluidity (ability of things to move around within the cell membrane like
membrane proteins? - ✔✔More unsaturated fats, because double bonds prevent them from
stacking together so tightly.
How does membrane fluidity change under cold temperatures? - ✔✔The cell increases the number
of unsaturated fatty acids in the membrane to help increase fluidity and avoid becoming rigid.
How does membrane fluidity change in response to warm temperatures? - ✔✔Increased
saturated fatty acids to prevent the membrane from becoming too fluid.
How does cholesterol effect fluidity of plasma membrane? - ✔✔In cold temperatures it sits
between phospholipids and prevents them from packing too closely together. In warm temperatures it
prevents excess movement. It is basically what keeps fluidity at a middle ground no matter what.
Is uracil a pyrimidine or purine? - ✔✔It is a pyrimidine just like thymine, its counterpart.
Difference between nucleoside and nucleotide? - ✔✔Nucleosides contain a 5 carbon sugar and
a base but lack a phosphate group.
,What type of bond connects nucleotides and what connects DNA? - ✔✔Phosphodiester
and hydrogen bonds.
In what prime directions do DNA strands run? - ✔✔5'-3'
Is DNA or RNA more reactive/unstable and why? - ✔✔RNA because of its extra hydroxyl group. It
is also single stranded which makes it more exposed.
Cohesion vs adhesion? - ✔✔Cohesion is the ability of a molecule to stick to itself. Is the same as
surface tension (hydrogen bonding between H20 molecules). Adhesion is like tape. Its the attraction
between unlike substances.
Capillary action and surface tension describe adhesion or cohesion? - ✔✔Capillary action is
adhesion, surface tension is cohesion.
What is unique about the density of water? - ✔✔It becomes less dense when freezing and
expands. This is because of hydrogen bonds formed in a crystal lattice that keep H2O molecules
farther apart from each other.
Why is H2O a strong solvent? - ✔✔Its dipole allows it to separate charged ionic molecules.
Can genetic information be passed backward from Protein back to nucleic acid or from protein to
protein? - ✔✔No
What are the two reasons that the RNA world hypothesis is supported? - ✔✔RNA can store
genetic material, but can also be catalytic.
What molecules can diffuse readily through the phospholipid bilayer? - ✔✔Small,
uncharged, nonpolar, hydrophobic
OR
,Small, uncharged, polar like CO2
Differences between peripheral, integral, and transmembrane proteins. - ✔✔Peripheral are
loosely attached to one surface of membrane
Integral are embedded inside the membrane
Transmembrane is a type of integral protein but spans the ENTIRE phospholipid bilayer.
What is the structure of a recognition protein and where are they found? - ✔✔Glycoprotein,
major-histocompatability complex on macrophages (MHC)
What type of membrane proteins are found in the kidney and plant root cells? - ✔✔Aquaporins
Are carrier proteins considered transmembrane? - ✔✔Yes, BUT they are only open to one side of
the membrane at a time.
What are adhesion proteins? - ✔✔Attach cells to each other and provide anchors for
internal filaments and tubules to increase stability.
Define glycocalyx and its purposes. - ✔✔Both glycolipids and glycoproteins that cover the outer
face of cells. Provides adhesion, protects against infection, and cell cell recognition.
Heterochromatin vs. euchromatin. - ✔✔Heterochromatin is tightly packed, euchromatin is
loosely packed.
Define nucleosome - ✔✔8 central histones + associated DNA and an H1 histone on the
outside keeping it all together.
, Nucleolus function - ✔✔Produces ribosomes within the nucleus by importing ribosomal proteins
from the cytoplasm and combining them with rRNA made within the nucleus. These form
ribosomal subunits that are exported into cytoplasm.
Define nuclear lamina and its function. - ✔✔Only found in eukaryotic cells! Dense network
of filaments and proteins. Provides support AND helps regulate DNA replication, cell division,
and chromatin organization.
Define nucleoid - ✔✔In prokaryotic cells it is where almost of all of the genetic material is found
since they lack a nucleus.
What is the nuclear envelope composed of? - ✔✔It is a phospholipid bilayer with nuclear pores.
Cytoplasm vs. Cytosol? - ✔✔Cytoplasm refers to the space within a cell including organelles,
cytosol, and everything EXCEPT the nucleus.
Cytoplasm ONLY the intracellular fluid that fills the cytoplasm.
What are the sizes of subunits of a Eukaryotic and Prokaryotic ribosome? - ✔✔The
eukaryotic ribosome is composed of 2 subunits: 60S + 40S = 80S unit.
▪ The two subunits are produced inside the nucleolus, then moved into the cytoplasm where
they assembled into a single 80S ribosomes (larger S value
indicates heavier molecule).
Prokaryote ribosome is composed of 50S + 30S = 70S.
Roles of the rough ER and where are its products sent? - ✔✔Creates glycoproteins by
attaching polysaccharides to polypeptides as they are assembled by ribosomes.
Products are exported or are sent to the membrane
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