Biology 1 Unit 2 Notes

Each cell-surface receptor has three main components:

1. an external ligand-binding domain 2. a hydrophobic membrane-spanning region 3. an intracellular domain inside the cell

Each turn of the citric acid cycle directly produces ________. - 2 ATP molecules - 1 GDP molecule - 3 NADH and 1 FADH2

3 NADH and 1 FADH2

ATP is made during ________. - the first half of glycolysis - the second half of glycolysis - both halves of glycolysis

? second half?

Signaling across gap junctions

A cell targets a cell connected by gap junctions

Endocrine signaling

A cell targets a distant cell through the bloodstream

Paracrine signaling

A cell targets a nearby cell

In active transport a symporter ________. - carries two different molecules in different directions - carries only one type of molecule. - carries two different molecules in the same direction

Carries two different molecules in the same direction

______ is triggered by growth factor ligands that usually bind to cell-surface receptors. - Epidermal growth factor (EGF) - Adrenaline - Cell division

Cell division

_____ involves the movement of hydrogen ions across a membrane. - Chemiosmosis - Q and Complex II - Complex I

Chemiosmosis

Intracellular mediators are small molecules that ________. - diffuse between cells directly connected by gap junctions - travel between nerve cells - send nerve impulses

Diffuse between cells directly connected by gap junctions

In the absence of oxygen, some organisms are able to convert glucose to energy via ________. - fermentation - aerobic cellular respiration - regenerative glycolysis

Fermentation

The light-independent reactions of photosynthesis occur in the stroma of chloroplasts and consist of what three steps? - fixation, reduction, and regeneration - decomposition, rearrangement, and synthesis - photosystem I, photosystem II, and cytochrome complex

Fixation, reduction, and regeneration

The final net products of ________ are 2 molecules of ATP and 2 NADH. - pyruvate oxidation - the citric acid cycle - glycolysis

Glycoloysis

Cell division is triggered by ________ ligands that usually bind to cell-surface receptors. - hormone - growth factor - dividing factor

Growth factor

The ________ the phospholipid bilayer prevent hydrophilic substances from passing straight through the plasma membrane. - hydrophobic tails in the center of - hydrophobic heads surrounding - physical size limitations of

Hydrophobic tails in the center of

Hydrophilic substances cannot pass straight through the plasma membrane due to the ________. - hydrophobic tails in the center of the bilayer - physical size limitations of the bilayer - hydrophobic heads surrounding the bilayer

Hydrophobic tails in the center of the bilayer

_______ proteins span all or part of the membrane. - Recognition - Peripheral - Integral

Integral

In what important way does receptor-mediated endocytosis differ from phagocytosis? - It does not involve the pinching off of membrane. - It transports only small amounts of fluid. - It brings in only a specifically targeted substance.

It brings in only a specifically targeted substance

What happens to the membrane of a vesicle after exocytosis? - It leaves the cell. - It fuses with and becomes part of the plasma membrane. - It is disassembled by the cell.

It fuses with and becomes part of the plasma membrane

Choose the best explanation of why the plasma membrane is a "fluid mosaic." - It is composed of chemically and physically similar parts that move freely in and out of the phospholipid bilayer. - It is composed of distinct parts that flow continuously between it and the cytoplasm. - It is composed of physically and chemically different parts that move throughout and around the phospholipid bilayer.

It is composed of physically and chemically different parts that move throughout and around the phospholipid bilayer

_____ generated by fermentation in muscles is sent to the liver for conversion back into pyruvic acid. - Lactic acid - Ethanol - Alcohol

Lactic acid

The light-dependent reactions of photosynthesis generate ________ and ________ to carry solar energy. - ATP; FAD - glucose; FAD - NADPH; ATP

NADPH; ATP

______ is a gas that serves as a ligand that acts to dilate blood vessels. - Carbon monoxide - Nitric oxide - Nitroglycerin

Nitric oxide

Facilitated transport is used to move ________ across a membrane. - ions - large molecules - gases

Not large molecules - Maybe ions?

The recognition of self facilitated by the ________ plays an important role in the immune response. - nuclear membrane - cell wall - plasma membrane

Plasma membrane

The triggering of a second messenger is a common response used to ________. - propagate a signal within a cell - terminate a signal within a cell - initiate a signal within a cell

Propagate a signal within a cell

The variation in responses from different cells to the same ligand is due to differences in ________. - protein expression - receptor types - signal amplification

Protein expression

Steroid hormones are one type of ________ used in cellular signaling. - hydrophilic ions - small hydrophobic ligands - water-soluble ligands

Small hydrophobic ligands

_______ that incorrectly respond to ________ are targeted for apoptosis to prevent damage to the organism. - T-cells; "self proteins" - Cellular receptors; foreign macromolecules - Phosphatases; kinases

T-cells; "self proteins"

All types of endocytosis include ________. - an electrochemical gradient - the formation of a plasma membrane channel specific to the target - the formation of a plasma membrane pocket around the target

The formation of a plasma membrane pocket around the target - Note: Endocytosis is NOT based on an electrochemical gradient

Yeast cells appear to have no ________ kinases. - threonine - serine - tyrosine

Tyrosine

_____ secrete mating factors in preparation for sharing genetic material with another of their species. - Bacteria - Fungi - Yeasts

Yeasts -Note: Mating factors serve as signal molecules between haploid yeast cells in preparation of yeast mating.

A carboxyl group is removed from pyruvate during its conversion into ________. - ATP - NAD, + - acetyl group

acetyl group

Phosphorylation of serine is often used to ________. - inhibit enzymes - activate enzymes - create a binding site

activate enzymes -Note: Phosphorylation of serine and threonine is often used to activate enzymes transduction pathways

Phosphorylation is the ________. - transfer of energy using phosphate groups as carriers - addition of a phosphate group to a molecule - removal of a phosphate group to a molecule

addition of a phosphate group to a molecule

T-cells that incorrectly respond to "self proteins" are targeted for ________ to prevent damage to the organism. - necrosis - apoptosis - reprogramming

apoptosis

In ________ signaling, a cell targets itself. - autocrine - paracrine - endocrine

autocrine

Four types of cell signaling

autocrine, paracrine, endocrine, Signaling across gap junctions

What is removed from pyruvate during its conversion into an acetyl group? - hydroxyl group - methyl group - carboxyl group

carboxyl group

The presence of ______ regulates the fluidity of a membrane in animal cells.

cholesterol

The same ligands are often used to initiate different signals in different cell types. The variation in response to the same ligands is due to - differences in protein expression in different cells - cell proliferation - a signal pathway can branch off toward different endpoints

differences in protein expression in different cells

An ________ arises from an ion's combined concentration gradient and electrical charge. - cellular gradient - electrochemical pressure - electrochemical gradient

electrochemical gradient

Yeast contribute to beer brewing by producing ________ during alcohol fermentation. - oxygen - ethanol - methanol

ethanol

The ligand-binding domain on a cell-surface receptor is also called the ________ ______.

extracellular domain

In order to ensure an adequate supply of NAD+ is regenerated, ________ must be utilized in low oxygen conditions. - fermentation - glycolysis - aerobic respiration

fermentation

______ is a specialized form of anaerobic cellular respiration. - Fermentation - Chemiosmosis - Photosynthesis

fermentation

Part of the light-independent reactions is known as ________ because it converts inorganic carbon dioxide into organic carbohydrates. - Fixation - reduction - regeneration

fixation

The best description of the plasma membrane is a ________. - cobblestone street - fluid mosaic - brick wall

fluid mosaic

Many ________ are able to disrupt G-protein-linked receptors. - infectious bacteria - fungi - viruses

infectious bacteria

Communication within a cell is called?

inracellular signaling

Communication between cells is called?

intercellular signaling

Which of the following fermentation methods can occur in animal skeletal muscles? - alcohol fermentation - propionic fermentation - lactic acid fermentation

lactic acid fermentation

______ reactions of photosynthesis generate NADPH and ATP to carry solar energy. - The light-dependent - The light-independent - Both the light-dependent and -independent

light-dependent

Bacterial biofilms help bacteria ________. - scavenge for food effectively - evade predators - minimize the effects of antibiotics

minimize the effects of antibiotics

Most of the chemical reactions involved in cell metabolism in living systems are of what type? - lipogenesis or fatty acidosis reactions - glucogenesis or sugar-making reactions - oxidation reduction or redox reactions

oxidation reduction or redox reactions

The driving force behind ________ is a concentration gradient from high to low molecule concentration. - reverse transport - active transport - passive transport

passive transport

_____ is the addition of a phosphate group to a molecule. - Phosphorylation - Dephosphorylation - Chemiosmosis

phosphorylation

Choose a common method used to transmit signals within cells. - phosphorylation, or the addition of a phosphate group to a molecule - termination of a second messenger - enzyme cleavage

phosphorylation, or the addition of a phosphate group to a molecule

The process of ________ produces simple sugars. - cellular respiration - photosynthesis - lactic acid fermentation

photosynthesis

______ provides the energized carbon needed by nearly all living things. - Lactic acid fermentation - Cellular respiration - Photosynthesis

photosynthesis

Some disorders, such as hypercholesterolemia, are related to a failure in ________. - pinocytosis - receptor-mediated endocytosis - phagocytosis

receptor-mediated endocytosis

The passing of electrons from one molecule to another in a cell is are known as ________. - influx reactions - redox reactions - coupled transfers

redox reactions

cAMP is used to activate an enzyme that in turn ________. - initiates cell signalling - regulates many metabolic pathways - activates protein kinase C (PKC)

regulates many metabolic pathways Note: cAMP is used to activate cAMP-dependent kinase, which in turn phosphorylates serine and threonine residues on targets to activate them.

Autocrine signaling

targets itself

The direct products from the citric acid cycle are ________. - final products of cellular respiration - temporary electron storage compounds - formed from the direct consumption of oxygen

temporary electron storage compounds

Plant pigments absorb energy from the ________ spectrum during photosynthesis. - visible light - infrared - electromagnetic

visible light