Biology: Life

Question 1

Metabolism

Answer 1

The sum of all chemical reactions in the body. Can be divided into catabolic and anabolic reactions.

Question 2

Catabolic Reactions

Answer 2

Break down large chemicals and release energy.

Question 3

Anabolic Reactions

Answer 3

Build up large chemicals and require energy.

Question 4

Ingestion

Answer 4

Acquisition of food and other raw materials.

Question 5

Digestion

Answer 5

The process of converting food into a usable soluble form so that it can pass through membranes in the digestive tract and enter the body.

Question 6

Absorption

Answer 6

Passage of nutrient molecules through through the lining of digestive tract into body proper. Absorbed molecules pass through cells lining the digestive tract by diffusion or active transport.

Question 7

Transport

Answer 7

The circulation of essential compounds required to nourish the tissues and removal of waste products from tissue.

Question 8

Assimilation

Answer 8

Building up of new tissues from digested good.

Question 9

Respiration

Answer 9

Consumption of oxygen by the body. Cells use oxygen to convert glucose into ATP, a ready source of energy for cellular activities.

Question 10

Excertion

Answer 10

Removal of waste products produced during metabolic processes.

Question 11

Synthesis

Answer 11

Creation of complex molecules from simple ones (anabolism).

Question 12

Regulation

Answer 12

The control of physiological activities. The body’s metabolism functions to maintain its internal environment in a changing external environment (Homeostasis). Irritability is the ability to respond to a stimulus and is part of regulation.

Question 13

Growth

Answer 13

An increase in size caused by a synthesis of new materials.

Question 14

Reproduction

Answer 14

Generation of additional individuals of a species.

Question 15

Enzymes

Answer 15

Organic catalysts. All living systems must have continuous-controlled chemical activity. Enzymes speed up or slow down chemical reactions, decreasing the activation energy.

They’re proteins, so thousands of enzymes can conceivably be formed. Many enzymes are conjugated proteins and have a nonprotein coenzyme. In this case, both components must be present for the enzyme to function.

Most enzyme reactions are reversible.

Question 16

Substrate

Answer 16

Enzymes may catalyze only one reaction of one specific class of closely related reactions. The molecule on which an enzyme acts is called the substrate.

Question 17

Active Site

Answer 17

An area on each enzyme to which the substrate binds.

Question 18

Lock and Key Theory

Answer 18

The spatial structure of an enzyme’s active site is exactly complementary to the spatial structure of its substrate.

Question 19

Induced Fit Theory

Answer 19

More widely accepted. Active site has flexibility of shape. When appropriate substrate comes, the active site changes to fit the substrate.

Question 20

Enzyme Optimal

Answer 20

Enzyme action and rate depend on several environmental factors. As temperature increases, rate increases, until an optimal temperature is reached. Beyond that, heat alters the active site deactivating the enzyme. The same applies for pH in the sense that getting more basic or acidic from the optimal pH will deactivate it.

Question 21

Competitive Inhibition

Answer 21

Molecules similar to the substrate can bind to the active site of the enzyme. This can prevent enzymes from being activated.

Question 22

Noncompetitive Inhibition

Answer 22

Substance forms strong covalent bonds with an enzyme and consequently may not be displaced by addition of excess substrate. So noncompetitive inhibition is irreversible. The substance (noncompetitive inhibitor) can be at, near, or remote from active site. Allosteric inhibition is when inhibition takes place at a site other then the active site. This will change the structure of the enzyme and therefor, the active site.

Question 23

Hydrolysis

Answer 23

Reaction used to digest large molecules into small components. Regulated by enzymes.

Question 24

Lactase

Answer 24

Hydrolyzes lactose to the monosaccharides glucose and galactose. Regulated by enzymes.

Question 25

Proteases

Answer 25

Degrade proteins to amino acids. Regulated by enzymes.

Question 26

Lipases

Answer 26

Break down lipids to fatty acids and glycerol. Regulated by enzymes.

Question 27

Synthesis Reactions

Answer 27

Catalyzed by same enzymes as hydrolysis reactions, but the directions are reversed. Required for growth, repair, regulation, protection, and production of food reserves (fat, glycogen).

Question 28

Cofactors

Answer 28

Nonprotein molecule many enzymes require to be activated. Can be metal cations or coenzymes.

Question 29

Prosthetic Groups

Answer 29

Cofactors that bind to enzyme by strong covalent bonds.

Question 30

Cell Theory

Answer 30

1) All living things are composed of cells.
2) The cell is the basic functional unit of life.
3) The chemical reactions of life take place inside the cell.
4) Cells arise only from pre-existing cells.
5) Cells carry DNA.

Question 31

Fluid Mosaic Model

Answer 31

The cell membrane consists of a phospholipid bilayer with proteins embedded throughout. The phospholipid molecules are arranged so that the long, nonpolar, hydrophobic, “fatty” chains of carbon and hydrogen face each other, with the phosphorus-containing, polar, hydrophilic heads facing outward. This way the membrane is permeable to both small, nonpolar hydrophocic molecules (oxygen), and small polar molecules (water).

Question 32

Carrier Proteins

Answer 32

Charged ions and molecules cross membrane with help of these.

Question 33

Nucleus

Answer 33

The nucleus controls the activities of the cell, including cell division. It’s surrounded by a nuclear membrane. The nucleus contains DNA, which is complexed with structural proteins called histones to form chromosomes. The nucleolus is a dense structure where rRNA synthesis occurs.

Question 34

Ribosome

Answer 34

Sites of protein production. Made by nucleolus.

Question 35

Endoplasmic Reticulum

Answer 35

A network of membrane-enclosed spaces involved in the transport of materials throughout the cell, particularly those destined to be secreted by the cell.

Question 36

Golgi Apparatus

Answer 36

Receives vesicles and their contents from the smooth ER, modifies them (glycosylation), repackages them into vesicles, and send them toward cell surfrace by exocytosis.

Question 37

Mitochondria

Answer 37

Sites of aerobic respiration within the cell and hence the suppliers of energy. Each composed of an outer and inner phospholipid bilayer.

Question 38

Cytoplasm

Answer 38

Most of cell’s metabolic activity occurs in this.

Question 39

Vacuoles/Vesicles

Answer 39

Membrane bound sacs involved in the transport and storage of materials that are ingested, secreted, processed, or digested by the cell. Vacuoles larger than vesicles and more likely to be found in plant cells.

Question 40

Centrioles

Answer 40

Involved in spindle organization during mitosis and are not bound by a membrane. Only in animals. They usually have a pair oriented at right angles to each other and lie in the centrosome region.

Question 41

Lysosomes

Answer 41

Membrane bound vesicles that contain hydrolytic enzymes involved in intracellular digestion. They break down ingested material. An injured or dying tissue may “suicide” by rupturing the lysosome membrane and releasing its hydrolytic enzymes (autolysis).

Question 42

Cytoskeleton

Answer 42

Supports cell, maintains its shape, and functions in cell motility. Comprised of microtubules, microfilaments, and intermediate filaments.

Question 43

Microfilaments

Answer 43

Solid rods of actin, which are important in cell movement as well as support. Muscle contraction is based on interaction of actin with myosin. Microfilaments move materials across plasma membrane.

Question 44

Hypertonic

Answer 44

When the cytoplasm of a cell has lower solute concentration than the extraceulluar medium and water flows out of the cell. Also called plasmolysis.

Question 45

Hypotonic

Answer 45

When the extracellular environment has smaller solute concentration than the cytoplasm, causing water to flow into cell making it swell or lyse (burst).

Question 46

Carrier Molecules That Facilitate Active Transport

Answer 46

Energy-Independent Carriers - facilitate the movement of compounds along a concentration gradient.

Symporters - move two or more ions or molecules.

Antiporters - exchange one or more ions/molecules for another ion/molecule.

Pumps - energy-dependent carriers (require ATP).

Question 47

Endocytosis

Answer 47

Where cell membrane invaginates, forming a vesicle that contains extracellular medium. Pinocytosis is the ingestion of fluids or small particles, and phagocytosis is the engulfing or large particles. Particles may bind to receptors on the cell membrane before being engulfed.

Question 48

Exocytosis

Answer 48

A vesicle in the cell fuses with the cell membrane and releases its contents to the outside.

Question 49

Brownian Movement

Answer 49

Kinetic energy spreads small suspended particles throughout the cytoplasm of the cell.

Question 50

Enzyme: Most Common pH Optimum

Answer 50

Most enzymes have optimal pH of 7.2.

Question 51

Pepsin pH Optimum

Answer 51

Pepsin works better in acidic stomach.

Question 52

Pancreatic Enzymes pH Optimum

Answer 52

Pancreatic enzymes work in more basic alkaline conditions of small intestine.

Question 53

Cyclosis

Answer 53

Transport in cytoplasm occurs by cyclosis (streaming movement in cell).

Question 54

Glycosylation

Answer 54

Process of Golgi apparatus modifying vesicles.