Midterm Study Guide

Question 1

What is the advantage of eukaryotic cells having specific organelles that have membranes?

Answer 1

Specific organelles can do specific reactions
All of the proteins/enzymes that are needed are located in the membrane of the organelle or in the organelle itself
The cell doesn’t need to go searching
Much more efficient
Isolate specific reactions

Question 2

How does epinephrine stimulate the breakdown of glycogen in liver cells? Look at the signal transduction pathway.

Answer 2

Epinephrine binds to a receptor because it cannot enter through the membrane on its own because it is a polar/water soluble. It activates the G-Protein adn activates a second messenger. There is a protein kinase involved. It will either inhibit or promote it. That is how it will start to breakdown glycogen. It occurs in liver cells because that is where glycogen is stored. Target cells=liver cells or muscle cells

Question 3

function of Plasma membrane

Answer 3

regulates what enters and leaves the cell

Question 4

function of Nucleus

Answer 4

a vessel to hold the genetic material

Question 5

function of Nucleolus

Answer 5

produces/synthesizes ribosomes

Question 6

function of Rough endoplasmic reticulum

Answer 6

helps in the folding process of the proteins that eventually go to the outside of the cell, helps make membranes (membrane synthesis), aids in the synthesis of secretory proteins, also adds carbs to proteins to make glycoproteins

Question 7

function of Smooth endoplasmic reticulum

Answer 7

synthesizes/makes lipids, detoxifies drugs and poisons, metabolizes carbs, stores calcium ions (+2 charge) (find a lot in liver cells)

Question 8

function of Lysosome

Answer 8

breaks down ingested substances and other cell macromolecules or damaged organelles to recycle them, has lysosomal/hydrolytic enzymes to breakdown things such as food brought in by a perimysium, apoptosis

Question 9

function of Golgi apparatus

Answer 9

sorts and packages materials into transport vesicles, modifies proteins, it can put carbohydrates and attach them to either proteins or lipids, synthesizes polysaccharides
For other parts of the cell or excretion

Question 10

function of Peroxisomes

Answer 10

oxidative organelles, vessel that contains enzymes that transfer hydrogen to other molecules, makes hydrogen peroxide, breaks down hydrogen peroxide into water and oxygen gas

Question 11

function of Mitochondria

Answer 11

“powerhouse of the cell”, site of cellular respiration, makes ATP

Question 12

function of Chloroplast

Answer 12

process is photosynthesis to make sugar/glucose for the cell (glucose=the cells food)

Question 13

function of Cell wall

Answer 13

only in plant, fungi, and prokaryotes; to protect the cell, give the cell structure

Question 14

function of Ribosomes

Answer 14

protein synthesis

Question 15

function of Chloroplast

Answer 15

photosynthesis

Question 16

Structures of the endomembrane system

Answer 16

(Inside-Out)
Nuclear envelope/Nucleus
Endoplasmic Reticulum (more likely rough but maybe smooth)
Golgi Apparatus (not directly attached to ER, a vesicles connects them)
Vesicles that turn into the Lysosomes/Peroxisomes (vesicles created by GA)
Plasma membrane (vesicles will become part of the membrane or fuse and dump contents out of the cell)
Molecules that go through this process are:
Proteins
Protein is coded in nucleus, goes to ER and is modified, packaged by GA, sent in vesicle, goes through plasma membrane
Lipids/other molecules
Wouldn’t necessarily start in nucleus but continues through the rest of the system

Question 17

What happens when an action potential reaches the synapse

Answer 17

Release neurotransmitters (by the action potential and opening of the calcium channel for the calciums to flow), neurotransmitters fuse through and then cross through the synaptic cleft into the cell dendrite of the next neuron by sodium channels (sodium would be inflexing from the surrounding fluid)

Question 18

Pathway of action potential

Answer 18

Dendrites
Cell body
Axon
Axon terminal
area between axon terminal and cell dendrite is the synaptic cleft
To the next cells dendrites
ETC… to reach an effector which is usually a muscle or gland

Question 19

Hypotonic solutions

Answer 19

Solution has low solute concentration and is less than that inside the cell; cell gains water, cell will swell/burst (will only burst in animal cells, plants the cell just becomes full because the cell wall holds it in)

Question 20

Hypertonic solution

Answer 20

Solution has high solute concentration and is greater than that inside the cell; cell loses water, cell becomes shriveled/crenated

Question 21

Isotonic solution

Answer 21

Solution that has a solute concentration that is equal to the inside the cell; no net water movement across the plasma membrane

Question 22

Positive Homeostasis/Feedback

Answer 22

Triggers mechanisms that amplifies the stimulus
Enhances changes to enable a system to move away from its equilibrium state and cause it to be more unstable
EX: child birth, clotting, lactation
Longer situation; overtime
Final Result: farther from homeostasis (it will eventually return but after it was enhanced)

Question 23

Negative Homeostasis/Feedback

Answer 23

A response that reduces, or “damps,” the stimulus
Buffers change to allow a system to stay at an equilibrium and cause it to be more stable
EX: body temperature, heart rate, breathing rate, blood pressure, etc…
Immediate situations
Final Result: bringing it back to normal/homeostasis

Question 24

What is the function of antidiuretic hormone (ADH)? How does it work

Answer 24

Endocrine system and Excretory system
Released from the pituitary gland and goes into the bloodstream to the target cells along the collecting duct
Binds to receptors and causes aquaporins to form in the collecting duct cells to reabsorb water from the collecting duct back into the body cells
Negative feedback
Once we receive enough water it will shut off
if the ADH is not working or the gene is never made then the person will release a lot of water and will have diluted urine

Question 25

Review the enzyme activation energy graph. Be able to identify the products, reactants, activation energy, ∆ G. What happens when enzymes are used

Answer 25

Amount of energy needed to get the chemical reaction going. In a normal reaction without enzymes a lot more energy is needed to get the reaction started.
delta G=differenceof free energy between reactants and products
products lower=negative
products higher=positive
zero=cell is dead
reaction process=time

Question 26

what do mutations do

Answer 26

Changes (mutations) in genes lead to changes in amino acid composition of an enzyme
The DNA polymerase misses it during proofreading

Question 27

substitution

Answer 27

One base is substituted (or a couple bases are substituted)
DNA polymerase did not pick it up when it proofread
Occurs during S phase, replication, or translocation
Might causes a different amino acid being made (may or may not depending on which letter the mutation is)

Question 28

deletion

Answer 28

This causes a frameshift mutation due to one letter missing
May change amino acid from there down or make a stop codon so a different protein is made
Chunks of genes on chromosomes can get deleted

Question 29

insertion

Answer 29

This causes a frameshift mutation due to a new letter
May change the amino acid or protein
Insertion of extra genes on chromosomes

Question 30

translocation

Answer 30

this can be on the DNA level due to a transposon because one letter can be moved
This can also move chunks of DNA in chromosomes
EXAMPLE:
Sickle-cell disorder:
A base pair substitution mutation that causes the disorder
An A gets mutated to a T on amino acid 6 of the long chain
Instead of glutamic acid being made valine is made
Beta subunit of hemoglobin are the units that get screwed up and cause poor oxygen intake and the wrong shape

Question 31

What happens at the neuromuscular junction between a neuron and a muscle fiber

Answer 31

The axon terminal on the neuron meets the muscle fiber.
An action potential comes down, calcium channels open, calcium rushes in, causes the vesicles with the neurotransmitters to fuse into the plasma membrane of the neuron and stay in the synaptic cleft, than the sodium channels in the muscle fiber are open causes the sodium ion channels to open (calcium binds and causes the sodium channels to open) and sodium flows into the muscle fiber
Same as neuron to neuron
If something blocks the sodium channels, sodium channels won’t open and the muscles will be weak and fatigued and won’t fire

Question 32

What do antibodies do?

Answer 32

B cells create the antibodies against the antigen. The B cells will recognize the specific antigen and bind to it when it is present and causes clumping so macrophages will come and get rid of it. Antibodies can be formed immediately on exposure or memory cells can create them
The antibodies build up to create the immune systems.
Circulate in the blood and lymph to recognize pathogens

Question 33

What is apoptosis? When is it used by cells? Give examples

Answer 33

Programmed cell death
It destroys the cells because the lysosomes break open, releasing hydrolytic enzymes/activating proteins that cause those particular cells to die.
EX:
Surface area to volume ratio is too high
Infected by pathogen
Tadpoles losing tails
=Embryonic development
Humans losing webbing between fingers
=Embryonic development

Question 34

What causes tumors? What conditions might cause tumors to grow?

Answer 34

Cancer-which is uncontrolled cell growth
Benign tumor is still considered cancer but not harmful
Conditions that cause them are mutations or malfunctions or something in a gene causing overgrowth of a cell

Question 35

Recombinants- what are they? How do they happen? What is their significance? How can you tell they are present? Think fruit flies

Answer 35

An organism that has both of the parents features
The ones that appear like the parents are not the recombinants
The ones that appear as a combination ARE the recombinants
Happens due to crossing over in prophase 1 of meiosis
Significant because it means crossing over occurs and leads to variation in the population which is better for evolution over time
You can tell they are present when comparing offspring to parents
Are they identical or a combination of the parents?

Question 36

What is a reflex arc? What are its components? How does it work? What might prevent it from working?

Answer 36

A reflex arc is a neuron pathway that consists of a minimum of two neurons and involved the PNS and CNS

Question 37

pathway of a reflex arc

Answer 37

Stimulus is picked up by the receptor
Then travels with the sensory neuron/Afferent
Goes to the spinal cord
Travels with the interneuron/Association
Then travels with the motor neuron/Efferent
Goes to the effector-which is muscle or gland
Not always 3 neurons

Question 38

example of reflex arc and what would happen if there is something wrong

Answer 38

Knee reflex (Effector would be the quad muscle)
If something is wrong with the sensory neuron then it never gets to the spinal cord and nothing occurs past there but it would be felt
If something is wrong with the interneuron it will reach the spinal cord/CNS but no muscle will interact
If something is wrong with the motor neuron it will go past the spinal cord but no knee jerk will occur

Question 39

Thyroxine hormone – What does it do? Where is it secreted from? Look at the feedback mechanism.

Answer 39

The hypothalamus releases TRH (Thyrotropin-Releasing Hormone) that tells the anterior pituitary to release TSH (Thyroid-Stimulating Hormone) and travels to the thyroid gland and releases thyroxine
If there is enough thyroxine then the pituitary stops production of the TSH or inhibits the hypothalamus to stop release of TRH
Thyroxine is involved with metabolism and the use of oxygen in the cells
Hyperthyroid=too much release without inhibition and there is a faster metabolism
Hypothyroid=not enough release and slower metabolism

Question 40

Where are proteins made in a cell? How do they get to where they need to go once they are made?

Answer 40

Proteins are made in ribosomes that are either in cytoplasm or Rough ER
If cytoplasms then they are used inside the cell
If rough ER they will end up outside the cell or the plasma membrane
ends up there due to vesicles and exocytosis

Question 41

What are the organisms that undergo fermentation? What are the products of fermentation?

Answer 41

Fermentation is a partial degradation of sugars that occurs without O2
Bacteria use fermentation
Lactic acid fermentation
Product of lactic acid fermentation=lactate
Some undergo alcohol but most use lactic acid
Yeast use fermentation
Alcohol fermentation
alcohol and carbon dioxide are products
Muscle cells
Lactic acid fermentation

Question 42

What are similarities in fermentation and cell respiration?

Answer 42

Both use glycolysis
Starting reactant is glucose and go through a 10 step process where the final net gain is 2 ATP (ADP+phosphate) (but used 2 in the beginning so total of 4) and 2 pyruvate and 2 NADH electron carrier
The products can go onto the krebs cycle or go through glycolysis again
Both have a final product of 2 atp, both use asp and phosphate, both start with glucose and glycolysis, both do not need oxygen present, both produce 2 pyruvate, and both produce 2 NADH

Question 43

What are cilia and flagella made out of? What organelle would be required to get them to work?

Answer 43

Motor proteins that are anchored to a hook area in the plasma membrane that swivels that causes the cilia or flagella to swivel.
Inside is made out of microtubules
Diagram
Organelle that is required would be the motor proteins
Mitochondria make the energy to get them to work

Question 44

If given a sequence of DNA, be able to transcribe it into mRNA, and translate it using the mRNA code into the amino acids.
EX: DNA: TACGTACGC

Answer 44

mRNA: AUGCAUGCG
Aminos: methionine (start), histidine, alanine

Question 45

How might a mutation in the DNA code affect a protein? What might it do to the structure?

Answer 45

Primary:
Made of a long chain of amino acids
Mutation may cause incorrect amino acids in the primary structure.
Secondary:
Still will probably have alpha helixs and beta pleths
Tertiary:
Is it a positive charge now? is it a negative charge now? Is it hydrophobic or hydrophilic? Does it contain sulfur?
The R groups characteristic determine the folding and hydrogen bonds; therefore, the incorrect protein will cause an incorrect folding into an incorrect structure
Quaternary:
Polypeptides that are made are incorrect and could be affected

Question 46

What types of diseases may be caused by mutations?

Answer 46

Sickle cell anemia, hemophilia, color blindness, cystic fibrosis, some are inherited

Question 47

What are some methods that could be used to determine if DNA has been mutated

Answer 47

DNA sequencing, deliberated mutate a gene to see the affects, analyze the structure of the protein, sequence the protein

Question 48

What is the function of oxygen in cell respiration? With that in mind, why is there more ATP produced in cell respiration vs. fermentation

Answer 48

Oxygen comes in during the electron transport chain
Located inside the mitochondria in the intermembrane
There are proteins in the membrane. Oxygen is waiting and is the final electron acceptor from the NADH and FADH2 which drop off electrons (NADH drops at bottom) (FADH drops at top).
There is more ATP produced in cell respiration than fermentation due to the electrons that are dropped off as a source of energy and the protons are released and pumped through to make a proton gradient and form pumps and allows it to make more ATP
Low pH due to the large amount of hydrogen protons

Question 49

What does the resting potential of a neuron membrane look like and what ions are located where?

Answer 49

At resting potential, positive charges are on the outside of the neuron and negative are on the inside. It is caused by the outside being positively charged so there are more positive charges-sodium-on the outside. And it is more negative on the inside and more potassium on the inside.

Question 50

How do hormones control the male reproductive system?

Answer 50

The major hormones, GnRH, LH, FSH, testosterone
GnRH signals the anterior pituitary to produce LH and FSH. It goes through the bloodstream. THe LH stimulates the leydig cells to produce and release testosterone. The FSH will trigger sertoli cells to start spermatogenesis (to make sperm). Testosterone (when there is enough) tells the hypothalamus to not release GnRH and there is no sperm production and testosterone
Negative feedback

Question 51

How does the impulse flow through two neurons

Answer 51

One neuron to another

The neurotransmitters in the synaptic cleft from dendrite to axon, neurotransmitters, dendrite to axon

Question 52

What happens to homologous pairs of chromosomes during prophase of meiosis I? How can you tell it’s happening

Answer 52

Crossing over occurs in meiosis 1.

This is when nonsister chromatids are involved with the exchange of corresponding segments of DNA molecules

Question 53

What does reverse transcriptase do?

Answer 53

An enzyme that helps RNA make DNA from its code

Programs host cell to convert viral RNA into DNA that can then be used as the code for protein synthesis

Question 54

What enzymes are involved in DNA replication

Answer 54

DNA polymerase, helicase, ligase, topoisomerase, primase

Leading and lagging strand

Question 55

Hershey Chase experiment

Answer 55

the scientist was wondering if the protein or DNA was inherited
Took viruses made out of protein coats with DNA inside and labeled the protein with radioactive sulfur and labeled the DNA with radioactive phosphorus. The vidurs infected the cell and found that the DNA was transferred. THey knew it because they detected the radioactive phosphorus.