Chapter 3

What structure separates the intracellular fluid from the extracellular fluid?

Plasma membrane

What model describes the plasma membrane as a moving lipid bilayer containing proteins?

Fluid mosaic model

What forms the basic structural fabric of the plasma membrane?

Phospholipid bilayer

Which part of a phospholipid is attracted to water?

Hydrophilic head

Which part of a phospholipid avoids water?

Hydrophobic tails

Where do the hydrophobic tails of membrane phospholipids point?

Toward the membrane interior

What membrane lipid helps stabilize and stiffen the membrane?

Cholesterol

What type of membrane protein is embedded within the lipid bilayer?

Integral protein

What type of membrane protein is attached to the membrane surface rather than embedded within it?

Peripheral protein

What are carbohydrates attached to proteins called?

Glycoproteins

What are carbohydrates attached to lipids called?

Glycolipids

What carbohydrate-rich coating contributes to cell recognition?

Glycocalyx

Which membrane function determines which substances may enter or leave a cell?

Selective permeability

Which type of cell junction forms a relatively impermeable seal between neighboring cells?

Tight junction

Which type of cell junction provides strong mechanical attachment between neighboring cells?

Desmosome

Which type of cell junction permits direct communication between neighboring cells?

Gap junction

In simple diffusion, substances generally move in which direction?

Down their concentration gradient

Does simple diffusion directly require ATP?

No

What passive process uses a membrane protein to move a substance down its concentration gradient?

Facilitated diffusion

What is the movement of water across a selectively permeable membrane called?

Osmosis

What type of solution causes a cell to lose water?

Hypertonic solution

What type of solution causes a cell to gain water?

Hypotonic solution

What type of solution causes no net gain or loss of cellular water?

Isotonic solution

Which transport process directly uses ATP to move a substance against its gradient?

Primary active transport

Which transport process uses energy stored in an ion concentration gradient?

Secondary active transport

What major membrane pump is an example of primary active transport?

Sodium-potassium pump

How many sodium ions are transported out during one sodium-potassium pump cycle?

Three sodium ions

How many potassium ions are transported into the cell during one sodium-potassium pump cycle?

Two potassium ions

How many ATP molecules are used per sodium-potassium pump cycle?

One ATP

Which ion is present at a higher concentration outside a typical cell?

Sodium

Which ion is present at a higher concentration inside a typical cell?

Potassium

What approximate sodium concentration did Goode emphasize for extracellular fluid?

140

What approximate potassium concentration did Goode emphasize for extracellular fluid?

5

What approximate sodium concentration did Goode emphasize for intracellular fluid?

5

What approximate potassium concentration did Goode emphasize for intracellular fluid?

140

What type of cotransporter moves two substances in the same direction?

Symporter

What type of cotransporter moves two substances in opposite directions?

Antiporter

What general process brings material into a cell using vesicles?

Endocytosis

What general process releases material from a cell using vesicles?

Exocytosis

What form of endocytosis brings large particles into a cell?

Phagocytosis

What form of endocytosis brings extracellular fluid and dissolved substances into a cell?

Pinocytosis

What form of endocytosis selectively takes up molecules after they bind membrane receptors?

Receptor-mediated endocytosis

What is the cellular region between the plasma membrane and nucleus called?

Cytoplasm

What is the fluid portion of the cytoplasm called?

Cytosol

What term describes nonliving stored materials within the cytoplasm?

Inclusions

Which organelle is the major site of ATP synthesis?

Mitochondrion

Which cellular structure is the site of protein synthesis?

Ribosome

Which organelle has ribosomes attached and is strongly associated with protein production?

Rough endoplasmic reticulum

Which organelle synthesizes lipids and steroids and participates in detoxification?

Smooth endoplasmic reticulum

Which organelle modifies, sorts, and packages proteins?

Golgi apparatus

Which organelle contains digestive enzymes used for intracellular digestion?

Lysosome

Which organelle helps detoxify harmful molecules and neutralize free radicals?

Peroxisome

Which cellular framework provides structural support and assists in movement?

Cytoskeleton

Which organelle organizes microtubules and contributes to formation of the mitotic spindle?

Centrosome

Which cellular extensions move material across the surface of a cell?

Cilia

Which cellular extension propels an entire cell, such as a sperm cell?

Flagellum

Which cellular extensions increase surface area for absorption?

Microvilli

Which structure encloses most of the cell's genetic material?

Nucleus

What structures inside the nucleus assemble ribosomal subunits?

Nucleoli

What does chromatin condense into during cell division?

Chromosomes

What are the three stages of interphase?

G1, S, and G2

During which stage of interphase does DNA replication occur?

S phase

What occurs primarily during G1?

Cell growth

What occurs primarily during G2?

Final preparation for cell division

What is division of the nucleus called?

Mitosis

What is division of the cytoplasm called?

Cytokinesis

What is the normal order of mitotic stages?

Prophase → metaphase → anaphase → telophase

What process produces an RNA copy from a DNA template?

Transcription

What process uses mRNA information to build a polypeptide?

Translation

Which RNA carries genetic instructions from DNA to the ribosome?

mRNA

Which RNA carries amino acids to the ribosome?

tRNA

Which RNA is an important structural component of ribosomes?

rRNA

Where does transcription occur in a typical human cell?

Nucleus

Where does translation occur?

Ribosomes in the cytoplasm

What three-base sequence on mRNA specifies an amino acid?

Codon

What complementary three-base sequence is found on tRNA?

Anticodon

What start codon did Goode emphasize for translation?

AUG