Biology 121 Wk. 5, 6,7

A toxin that inhibits the production of GTP would interfere with the function of a signal-transduction pathway that is initiated by the binding of a signal molecule to _____ receptors.

A G-protein-linked receptor activates G protein, which activates phospholipase C, which cleaves a membrane protein to form IP3, which binds to a calcium channel on the ER, which opens to release calcium ions into the cytoplasm, which bind to an intracellular enzyme that carries out a response.

What are ligands?

A ligand is a molecule that bind to a much larger and specific molecule. The binding process causes receptor proteins to change shape due to its binding.

What is the Plasma Membrane?

A phosphilipid bi-layer studded with protiens: surrounds the cell. Surrounds the outside of both Eukaryotic and Prokaryotic cells.

What is synaptic signaling?

A type of local signaling that allows for the nervous system to receive signals through chemical molecules which are travels through the nerve synapse to reach and be interpreted by the brain.

*Differentiate between saturated and unsaturated fatty acids.

Also include the difference between cis and trans fatty acids. saturated have max # of hydrogens bond to the single carbon (C-C). Unsaturated have less than the max # of hydrogens bonded to the carbon (C=C or triple bond)

What is an Endoplasmic Reticulum?

An extensive network of membranes called tubuels and vesicles.

Which two functional groups are always found in amino acids? A)ketone and methyl B)carbonyl and amino C)carboxyl and amino D) hydroxyl and carboxyl

Carboxyl and amino

The Golgi receives vesicles from the ER on the _____ side.

Cis

*Explain the two major functions of Lysosomes.

Lysosomes are responsible for phagocytosis and autophagy. Phagocytosis is the process of amoebas and protists eating and engulfing smaller organisms and food particles. Autophagy is process of the lysosome recycling its organic material by using hydrolytic enzymes.

What is the function of Lysosomes?

Membrane enclosed organells which leaks enzymes to break down polymers—proteins, nucleic acids, carbohydrates, and lipids.

What is Rough ER?

Membranous tubes with ribosomes embedded

What is Smooth ER?

Membranous tubes without ribosomes

What is the function Mitochondria?

Mitochondria functions as the powerhouse of the cell since it produces ATP from sugar and other organic molecules.

Chloroplasts are found in what type of organisms?

Plant cells which are 'producers'

Explain with an example and a diagram the difference between the polar and non-polar covalent bonds.

Polar bonds are the unequal sharing a electronegative atoms pull harder Example: H20. Nonpolar bonds are the equal sharing Example: H-H

What is the function of the Golgi apparatus?

Proteins produced from the ER are modified, stored, and then sent to other destinations.

Which of these receptors is NOT a membrane receptor? G-protein link receptor Tyrosine kinase receptor Ion channel receptor Correct Response Receptor for testosterone

Receptor for testosterone

The nuclear envelope is connected to the __________ of the cell.

Rough ER

When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway? a. receptor b. relay molecule c. transducer d. signal molecule e. endocrine molecule

Signal Molecule

What are Lysosomes?

Small, spherical bodies containing hydrolytic enzymes

involved in detoxifying poisons?

Smooth ER

______________ ER lacks ribosomes and is attached to the ends of the ______________________.

Smooth; rough

Explain why before a protein leaves the ER carbohydrates are attached to it.

So the protein knows where it should be secreted out They are tags that the cell can read and tell what each are supposed to do.

What is the Golgi apparatus?

Stack of flattened membranous sacs near the ER

Which of the following statements concerning saturated fats is NOT true? A)They have multiple double bonds in the carbon chains of their fatty acids B)They generally solidify at room temperature C)They contain more hydrogen than unsaturated fats having the same number of carbon atoms D) They are one of several factors that contribute to atherosclerosis

They have multiple double bonds in the carbon chains of their fatty acids

What is the function of the Endoplasmic Reticulum?

Transports Proteins through its networks.

True Or False. Active transport of substance involves ATP expenditure and the molecules are transferred from low to high concentration area.

True

True or False. On food packages, the term insoluble dietary fiber refers to the polymer called cellulose.

True

True or False. Protein kinase are the enzymes that are involved in adding a phosphate group to a protein molecule.

True

_____________ is the protein in microfilaments, while ____________ is the protein in microtubules

actin; tubulin

What is the function of the Rough ER?

aids in synthesis of secretory and other proteins from bound ribosomes; adds carbohydrates to proteins to make glycoproteins; produces new membrane.

G-protein-linked receptors _____; whereas tyrosine-kinase receptors _____.

are not enzymes ... have enzymatic function

___________ acts on surface receptors of the same cell that produced it.

autocrine signals

Phospholipids are amphipathic molecules. It means that they have.

both hydrophobic and hydrophilic regions

If a drug inhibits the enzyme activity of Phosphodiesterase, an enzyme which inactivates cAMP by converting it to AMP, it will increase the concentration of:

cAMP

Which of these acts as a second messenger? Correct Response cAMP G protein Protein kinase Tyrosine kinase

cAMP

The activation of receptor tyrosine kinases is characterized by:

dimerization and phosphorylation

Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. Thus, lactose is classified as a

disaccharide.

Which of the following is a function of microtubules?

forming a structural component of cilia

_____________ looks like stacks of flattened sacs and have shipping or ___________face and a receiving or __________face.

golgi complex; trans; cis

Kinases and phosphatases are essential in the cell because they

help turn proteins "on and off" through changes in phosphorylation status.

Cells use different signaling strategies to achieve different goals. In hormonal signaling-

specialized cells release hormone molecules into the circulatory system, permitting distant cells to be affected

Endomembrane of ER is connected with the cis side of the golgi complex via ________.

transport vesicle

A cell biologist has developed a new drug that will block the cis face of the Golgi apparatus. If eventually approved by the FDA, she wants to use this new drug to aid cancer patients. What specifically will this drug prevent from happening inside a cancer cell?

transport vesicles from ER cannot fuse with golgi complex

*Differentiate between ionic and covalent compounds? Ionic bonds are the transfer of electrons (metal and non).

Covalent bonds are the sharing of electrons (non and non).

True or False. The double bonds in the saturated fatty acid, that are present in the hydrophobic tails of the membrane phospholipids, form kinks that prevent adjacent lipids from packing tightly and thus assists in keeping the membrane fluid.

False

If a cell had 10% solute concentration and its environment had 25% solute concentration, what direction would osmosis occur?

From inside of the cell to the environment

When a cell responds to epinephrine that binds to _________, it increases the concentration of Glucose-1-phosphate.

G-protein linked receptor

A G protein is active when _____.

GTP is bound to it

are examples of monosaccharides.

Glucose and fructose

Usually the ligands that bind to the cell membrane receptors are hydrophobic.

?

What are Ribosomes?

They are tiny spherical bodies composed of RNA & protein.

Where can Ribosomes be found?

They can be found in the cytoplasm of a living cell.

What is the function of Ribosomes?

They function as factories which translate genetic information, or DNA, from the nucleus into usable protein molecules.

The component that gives shape to the nucleus and protects DNA from external forces is?

nuclear lamina

What name is given to the process by which water crosses a selectively permeable membrane?

osmosis

The cell membranes are composed of a double layer of _________________

phospholipids

The general name for an enzyme that transfers phosphate groups from ATP to a protein is _____.

protein kinase

Beta cells of the pancreas secrere a protein called insulin. There fore the cell component that would be present in relatively higher amounts within these cells would be?

rough ER

Which level of protein structure do the α helix and the β pleated sheet represent?

secondary

What aspects of protein structure are stabilized or assisted by hydrogen bonds?

secondary, tertiary, and quaternary structures, but not primary structure

Match the descriptions below to the cell organelle that is the best fit. -Organelle in which proteins are made -have DNA in nucleoid -This phospholipid bilayered membrane protects the nucleus -contain large number of lysozomes

-Ribosomes -prokaryotes -Nuclear membrane -Macrophage (white blood cell) that engulfs bacteria

What is the significance of selective permeability to biological membranes?

-Selective permeability permits the selective uptake of nutrients and the elimination of wastes. -Selective permeability prevents toxic materials from entering the cell. -Selective permeability allows cells to concentrate particular ions on either side of the membrane. -Selective permeability allows the plasma membrane to control traffic into and out of the cell it surrounds. -All of the a

What is Mitochondria?

...

Explain how do vesicles that bud off of the Golgi "know" where to go.

During protein secretion, in the endomembrane system, proteins bound for different destinations are given different carbohydrate "tags." Then the proteins are sorted in the Golgi and transport vesicles bud from the golgi and travel to the destination. The proteins on the vesicle surface interact with receptors at destination and the vesicle delivers the content.

Cells of the pancreas will incorporate radioactively labeled amino acids into proteins. This "tagging" of newly synthesized proteins enables a researcher to track the location of these proteins in a cell. In this case, we are tracking an enzyme that is eventually secreted by pancreatic cells. Which of the following is the most likely pathway for movement of this protein in the cell?

ER → Golgi → vesicles that fuse with plasma membrane

Protists, plants, fungi, and animals are all composed of _________________ cell, whereas bacteria and archaea have _____________________ cells.

Eukaryotic, prokaryotic

Materials can move out of the cell through the process of?

Exocytosis

Insulin is a protein molecule, so its receptor will be________?

Extracellular

What are intracellular and extracellular signaling molecules?

Intracellular molecules are molecules that are found in the cytoplasm and nucleus of the target cells. A chemical messenger reaches the receptor by passing through the cells plasma membrane.

What happens to ionic compounds when they dissolve in water?

Ionic compounds decompose in water- dissolving

What is the function of the Plasma Membrane?

It acts as a barrier between the inside of the cell and the outside (gate).

What is the function of the Nucleolus?

It functions as the control center of the cell and houses genetic information.

What is paracrine signaling?

Its signaling of near cells for cell growth and division.

What is the Nucleolus?

Its the spherical organelle within the nucleus.

Which of the following molecules or ions would normally need to use a membrane protein in order to move through the cell membrane?

Na+

Does Ca2 pass through the plasma membrane?

No

Does Cl- pass through the plasma membrane?

No

Does Glucose pass through the plasma membrane?

No

Does Ka+ pass through the plasma membrane?

No

Does Na+pass through the plasma membrane?

No

Does Protein pass through the plasma membrane?

No

*What types of proteins do the differently localized ribosomes produce?

The ribosome attached to the Endoplasmic Reticulum(rough) secrete rRNA and protein out of the cell or is free in the cytoplasm

What is the function of the smooth ER?

The smooth ER is responsible for the synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons, and storage of calcium ions.

What is the structure and function of microtubules?

The structure is straight hollow tubes composed of globular proteins called TUBULINS. Functions are... -maintenance of cell shape -cell motility (cilia or flagella) -provides anchors for organelles -acts as tracks for organelle movement--> transport vesicles help vesicles "walk" on cytoskeleton

What is the structure and function of microfilaments (actin)?

The structure is two intertwined strands of actin -maintenence of cell shape -changes in cell shape -muscle contraction -cell division

*Distinguish between the types of membrane proteins.

There are 50 different types of proteins but there are two major groups called Integral and Peripheral proteins. Integeral proteins can go through the hydrophobic interior of the lipid bilayer. Peripheral proteins are not embedded in the lipid bilayer at all. Instead, they are loosely bound to the surface of the protein, often connected to integral proteins.

What is the difference between chromosomes and chromatin?

They are both the same but have different structures. Chromosomes are uncondensed while Chromatin is a condensed DNA structure

In which type of cells can Mitochondria be found?

They are found in all eukaryotic cells.

Does CO2 pass through the plasma membrane?

Yes

Does H2O pass through the plasma membrane?

Yes

Does O2 pass through the plasma membrane?

Yes

Humans can digest starch but not cellulose because? A) the monomer of starch is glucose, while the monomer of cellulose is galactose B)humans have enzymes that can hydrolyze the glycosidic linkages of starch but not the type of glycosidic linkages that are present in cellulose C)the monomer of starch is glucose, while the monomer of cellulose is glucose with a nitrogen-containing group D)humans harbor starch-digesting bacteria in the digestive tract

humans have enzymes that can hydrolyze the glycosidic linkages of starch but not the type of glycosidic linkages that are present in cellulose.

Cell membrane is selectively permeable. Therefore, it will allow which of the following molecules to freely pass through its lipid bilayer?

hydrophobic molecules

When you compare the plasma membrane (yellow) between the two figures, you know that this cell is in a(n) _____ solution because the cell _____. (hint: compare the levels of the two membranes - do you see any increase - when does it happen?)

hypotonic ... swelled

A carrier transport membrane protein would be categoried as an?

integral membrane protein

A difference between the mechanisms of cAMP and Ca2+ in signal transduction is that cAMP _____ and Ca2+ _____.

is synthesized by an enzyme in response to a signal ... released from intracellular stores

A signal molecule is also known as a

ligand

Which of the following structures is responsible for digestion of cell contents after the death of a cell

lysosome

The ______________ is the powerhouse of the cell and generates cellular _________.

mitochondria; ATP