Cell Biology | ABSITE Slayer | AccessSurgery

TEST TAKING TIP

Test Taking Tip

Often complex cell biology is hidden within a question seemingly about a clinical scenario. If you can parse the implied question from the background without wasting time on superfluous information, you will have the best chance at efficiently making progress through tough questions.

CELL WALL

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Which cell wall component increases membrane fluidity?

Cholesterol

What are the 3 main lipid classes found in the cell membrane?

Phospholipids, cholesterol, and glycolipids

What percentages of protein, carbohydrate, and lipid compose the plasma membrane?

Protein: 60%, carbohydrate: 1% to 10%, and lipid: 40%

What are the most common phospholipids in the plasma membrane?

Phosphatidylethanolamine and phosphatidylcholine

Which portion of the cell wall provides capacitance (ability to store charge)?

Lipid portion of plasma membrane

Which portion provides ability to resist charge?

Protein portion

What is the difference between surface antigens in the ABO system versus HLA system?

ABO = glycolipids
HLA = glycoproteins

Name the adhesion molecules that anchor a cell to other cells or the extracellular matrix:

Desmosomes/hemidesmosomes

Cell-cell occluding junctions that form an impermeable barrier:

Tight junctions

Toxic portion of lipopolysaccharide complex:

Lipid A

CELL STRUCTURES

Listen

Name the thin filaments that interact with myosin:

Actin

Name the thick filaments that slide along actin utilizing ATP:

Myosin

Intermediate filament found in hair and nails:

Keratin

Intermediate filament found in muscle:

Desmin

Intermediate filament found in fibroblasts:

Vimentin

Form specialized cellular structures such as mitotic spindles, cilia, and neuronal axons; forms lattice inside the cell to aid in transport of organelles in cell:

Microtubules

Specialized microtubule that form spindle fibers during cell division:

Centriole

Structural component of cell that synthesizes exported proteins:

Rough endoplasmic reticulum

Structural component of cell that detoxifies drugs and is involved with lipid/steroid synthesis:

Smooth endoplasmic reticulum

Structural component of a cell that uses carbohydrates to modify proteins and targets proteins to lysosomes:

Golgi apparatus

Structure inside the cell that has a double membrane with an outer membrane that is continuous with the rough endoplasmic reticulum:

Nucleus

Structure inside the nucleus where ribosomes are made:

Nucleolus

Cell structure responsible for energy production:

Mitochondria

GENETICS

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Consists of proteins, histones, and double-stranded helical DNA

Chromosomes

Adenine and guanine are examples of:

Purines

Cytosine, thymidine, and uracil are examples of:

Pyramidines

FIGURE 1-1.

Four major steps in the control of eukaryotic gene expression. Transcriptional and posttranscriptional control determine the level of mRNA that is available to make a protein, whereas translational and posttranslational control determine the final outcome of functional proteins. Note that posttranscriptional and posttranslational controls consist of several steps. (Reproduced from Brunicardi FC, Andersen DK, Billiar TR, et al. Schwartz's Principles of Surgery. 9th ed. http://www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)

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Process by which ribosomes use mRNA as a template for synthesis of proteins:

Translation

Process by which RNA polymerase uses a DNA strand for synthesis of mRNA:

Transcription

Place where transcription takes place:

Nucleus

Sequence of the start codon:

AUG

Coils of DNA that are the basic units of DNA packaging:

Nucleosomes

Small basic proteins that nonspecifically bind with DNA segments:

Histones

Formed by the coiling of 6 or more nucleosomes by the histone H1:

Solenoids

Proteins are synthesized from:

mRNA

Enzyme involved in the unwinding of DNA:

DNA helicase

Enzyme used to catalyze the formation of the RNA primers used to initiate DNA synthesis:

DNA primase

Enzyme that links DNA fragments by degrading RNA primers:

DNA ligase

Type of mutation that results in a single amino acid change from a point mutation:

Missense mutation

Type of mutation resulting in a change in a single base pair:

Point mutation

Type of mutation occurring from a point mutation that results in replacement of an amino acid with a stop codon:

Nonsense mutation

Type of mutation that occurs with the addition or deletion of a few base pairs:

Frameshift mutation

Technique by which DNA can be amplified a billion-fold by utilizing synthesized primers/oligonucleotides to complement a strand of DNA:

Polymerase chain reaction

Noncoding regions that interrupt eukaryotic genes:

Introns

Process by which introns are removed from an RNA transcript:

Splicing

RECEPTORS AND SIGNALS

Listen

Platelet-derived growth factor, epidermal growth factor, and transforming growth factor alpha belong to this receptor family:

Tyrosine kinase receptor

Activated by calcium and diacylglycerol:

Protein kinase C

Activated by cAMP:

Protein kinase A

Enzyme that converts membrane phosphoinositols into IP3 and DAG:

Phospholipase C

Mediates release of calcium from sarcoplasmic reticulum in muscle, endoplasmic reticulum, and mitochondria:

IP3

Works with calcium to activate protein kinase C:

DAG

FIGURE 1-2.

A simplified view of the apoptosis pathways. Extracellular death receptor pathways include the activation of Fas and tumor necrosis factor receptors, and consequent activation of the caspase pathway. Intracellular death pathway indicates the release of cytochrome c from mitochondria, which also triggers the activation of the caspase cascade. During apoptosis, cells undergo DNA fragmentation, nuclear and cell membrane breakdown, and are eventually digested by other cells. (Reproduced from Brunicardi FC, Andersen DK, Billiar TR, et al. Schwartz's Principles of Surgery. 9th ed. http://www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)

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Enzyme that breaks down ATP to cAMP with release of pyrophosphate:

Adenylate cyclase

Most critical component in neovascularization in tumor metastases:

VEGF receptor

Cellular process under the precise control of different extra- and intracellular signals and follows a fixed sequence of events leading to cell death:

Apoptosis

Steroid hormones bind receptor in:

Cytoplasm

Thyroid hormone binds receptor in:

Nucleus

Examples of cAMP-dependent hormones:

TSH, ACTH

CELL TRANSPORT

Listen

Type of cell transport that uses concentration gradient as a driving force:

Diffusion (CO₂, O₂, and urea)

Type of diffusion that utilizes a carrier and is saturable:

Facilitated diffusion

Type of cell transport that requires ATP for energy:

Active transport

CELLULAR ENERGY

Listen

One glucose molecule generates:

Two ATP and 2 pyruvate molecules

Name of cycle where NADH and FADH₂ are created from the 2 pyruvate molecules produced from the breakdown of glucose.

Krebs cycle

Overall number of ATP generated from 1 molecule of glucose:

38 ATP: 36 from Krebs cycle + 2 ATP from glycolysis

Process by which amino acids and lactic acid via the Cori cycle are converted into glucose:

Gluconeogenesis

Name the breakdown product of fat metabolism that cannot be converted back into pyruvate:

Acetyl CoA

Lipases act on lipids to form:

Fatty acids and monoacylglycerols

FIGURE 1-3.

The recycling of peripheral lactate and pyruvate for hepatic gluconeogenesis is accomplished by the Cori cycle. Alanine within skeletal muscles can also be used as a precursor for hepatic gluconeogenesis. During starvation, such fatty acid provides fuel sources for basal hepatic enzymatic function. RBC, red blood cell; WBC, white blood cell. (Reproduced from Brunicardi FC, Andersen DK, Billiar TR, et al. Schwartz's Principles of Surgery. 9th ed. http://www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)

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Fatty acid utilization:

Short chain = direct transport to liver
Long chain = packaged into micelles into lymph

CELL CYCLE

Listen

Most variable part of the cell cycle that determines cell cycle length:

G1

Part of cell cycle where protein synthesis and chromosomal duplication occur:

S

Growth factors affect the cell during this phase of the cell cycle:

G1

Phase between S phase and M phase:

G2

Part of cell cycle where nucleus divides:

M

Tumor cells are most sensitive to radiation during this stage of the cell cycle:

M

Phase of mitosis where chromosomes shorten, nucleolus and nuclear envelope disappear, and spindle apparatus forms:

Prophase

Phase of mitosis where centromeres align on the equatorial plate, spindle fibers attach to the centromeres, and centromeres duplicate:

Metaphase

FIGURE 1-4.

The cell cycle and its control system. M is the mitosis phase, when the nucleus and the cytoplasm divide; S is the phase when DNA is duplicated; G1 is the gap between M and S; G2 is the gap between S and M. A complex of cyclin and cyclin-dependent kinase (CDK) controls specific events of each phase. Without cyclin, CDK is inactive. Different cyclin/CDK complexes are shown around the cell cycle. A, B, D, and E stand for cyclin A, cyclin B, cyclin D, and cyclin E, respectively. (Reproduced from Brunicardi FC, Andersen DK, Billiar TR, et al. Schwartz's Principles of Surgery. 9th ed. http://www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved.)

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Phase of mitosis where chromatids migrate to opposite poles:

Anaphase

Phase when nucleolar and nuclear envelope re-form and chromosomes decondense:

Telophase

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Jump to a Section

Which cell wall component increases membrane fluidity?

What are the 3 main lipid classes found in the cell membrane?

What percentages of protein, carbohydrate, and lipid compose the plasma membrane?

What are the most common phospholipids in the plasma membrane?

Which portion of the cell wall provides capacitance (ability to store charge)?

Which portion provides ability to resist charge?

What is the difference between surface antigens in the ABO system versus HLA system?

Name the adhesion molecules that anchor a cell to other cells or the extracellular matrix:

Cell-cell occluding junctions that form an impermeable barrier:

Toxic portion of lipopolysaccharide complex:

Name the thin filaments that interact with myosin:

Name the thick filaments that slide along actin utilizing ATP:

Intermediate filament found in hair and nails:

Intermediate filament found in muscle:

Intermediate filament found in fibroblasts:

Form specialized cellular structures such as mitotic spindles, cilia, and neuronal axons; forms lattice inside the cell to aid in transport of organelles in cell:

Specialized microtubule that form spindle fibers during cell division:

Structural component of cell that synthesizes exported proteins:

Structural component of cell that detoxifies drugs and is involved with lipid/steroid synthesis:

Structural component of a cell that uses carbohydrates to modify proteins and targets proteins to lysosomes:

Structure inside the cell that has a double membrane with an outer membrane that is continuous with the rough endoplasmic reticulum:

Structure inside the nucleus where ribosomes are made:

Cell structure responsible for energy production:

Consists of proteins, histones, and double-stranded helical DNA

Adenine and guanine are examples of:

Cytosine, thymidine, and uracil are examples of:

FIGURE 1-1.

Process by which ribosomes use mRNA as a template for synthesis of proteins:

Process by which RNA polymerase uses a DNA strand for synthesis of mRNA:

Place where transcription takes place:

Sequence of the start codon:

Coils of DNA that are the basic units of DNA packaging:

Small basic proteins that nonspecifically bind with DNA segments:

Formed by the coiling of 6 or more nucleosomes by the histone H1:

Proteins are synthesized from:

Enzyme involved in the unwinding of DNA:

Enzyme used to catalyze the formation of the RNA primers used to initiate DNA synthesis:

Enzyme that links DNA fragments by degrading RNA primers:

Type of mutation that results in a single amino acid change from a point mutation:

Type of mutation resulting in a change in a single base pair:

Type of mutation occurring from a point mutation that results in replacement of an amino acid with a stop codon:

Type of mutation that occurs with the addition or deletion of a few base pairs:

Technique by which DNA can be amplified a billion-fold by utilizing synthesized primers/oligonucleotides to complement a strand of DNA:

Noncoding regions that interrupt eukaryotic genes:

Process by which introns are removed from an RNA transcript:

Platelet-derived growth factor, epidermal growth factor, and transforming growth factor alpha belong to this receptor family:

Activated by calcium and diacylglycerol:

Activated by cAMP:

Enzyme that converts membrane phosphoinositols into IP3 and DAG:

Mediates release of calcium from sarcoplasmic reticulum in muscle, endoplasmic reticulum, and mitochondria:

Works with calcium to activate protein kinase C:

FIGURE 1-2.

Enzyme that breaks down ATP to cAMP with release of pyrophosphate:

Most critical component in neovascularization in tumor metastases:

Cellular process under the precise control of different extra- and intracellular signals and follows a fixed sequence of events leading to cell death:

Steroid hormones bind receptor in:

Thyroid hormone binds receptor in:

Examples of cAMP-dependent hormones:

Type of cell transport that uses concentration gradient as a driving force:

Type of diffusion that utilizes a carrier and is saturable:

Type of cell transport that requires ATP for energy:

One glucose molecule generates:

Name of cycle where NADH and FADH2 are created from the 2 pyruvate molecules produced from the breakdown of glucose.

Overall number of ATP generated from 1 molecule of glucose:

Process by which amino acids and lactic acid via the Cori cycle are converted into glucose:

Name the breakdown product of fat metabolism that cannot be converted back into pyruvate:

Lipases act on lipids to form:

FIGURE 1-3.

Fatty acid utilization:

Most variable part of the cell cycle that determines cell cycle length:

Part of cell cycle where protein synthesis and chromosomal duplication occur:

Growth factors affect the cell during this phase of the cell cycle:

Phase between S phase and M phase:

Part of cell cycle where nucleus divides:

Tumor cells are most sensitive to radiation during this stage of the cell cycle:

Phase of mitosis where chromosomes shorten, nucleolus and nuclear envelope disappear, and spindle apparatus forms:

Phase of mitosis where centromeres align on the equatorial plate, spindle fibers attach to the centromeres, and centromeres duplicate:

FIGURE 1-4.

Name of cycle where NADH and FADH₂ are created from the 2 pyruvate molecules produced from the breakdown of glucose.