Chapter 9.5: Apoptosis in Cells

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Questions and Answers

Apoptosis is also known as ______ cell death.

programmed

Damaged cells or cells that reached the end of their functional lives are chopped and packaged into ______ and digested by scavenger cells.

vesicles

Ced-9 is an ______ inhibiting protein.

apoptosis

Cytochrome C functions in ______ electron transport but acts as a cell death factor when released.

mitochondrial Signup and view all the answers

Internal signals can result from ______ DNA damage or excessive protein misfolding.

irreparable Signup and view all the answers

Cells use chemical energy stored in ______ molecules to generate ATP.

organic Signup and view all the answers

Catabolic pathways release stored energy by breaking down ______ molecules.

complex Signup and view all the answers

Fermentation is a type of ______ degradation of sugars that occurs without O2.

partial Signup and view all the answers

The Calvin cycle uses ______ and NADPH to reduce CO2 to sugar

ATP Signup and view all the answers

In the Calvin cycle, carbon enters as ______ and leaves as a sugar, glyceraldehyde 3-phosphate (G3P)

CO2 Signup and view all the answers

For net synthesis of 1 G3P, the Calvin cycle must take place ______ times, fixing 3 CO2 molecules

3 Signup and view all the answers

In C4 plants, the enzyme ______ catalyzes production of 4-carbon precursors in mesophyll cells

PEP carboxylase Signup and view all the answers

In CAM plants, stomata open at ______ to incorporate CO2 into organic acids

night Signup and view all the answers

During photorespiration, rubisco adds ______ instead of CO2 in the Calvin cycle, producing a 2-carbon compound

O2 Signup and view all the answers

In C4 plants, ______ cells are arranged in tightly packed sheaths around the veins of the leaf

Bundle-sheath Signup and view all the answers

The Calvin cycle has 3 phases, including carbon ______, reduction, and regeneration of CO2 acceptor (RuBP)

fixation Signup and view all the answers

In the presence of ______, pyruvate enters the mitochondrion, where oxidation of glucose is completed.

O2 Signup and view all the answers

Microtubules shorten by depolymerizing at their ______ ends.

kinetochore Signup and view all the answers

Pyruvate must be converted to ______ CoA, which links glycolysis to citric acid cycle.

acetyl Coenzyme A Signup and view all the answers

In telophase, genetically identical daughter ______ form at opposite ends of the cell.

nuclei Signup and view all the answers

Cytokinesis begins during ______ or telophase and the spindle disassembles.

anaphase Signup and view all the answers

The citric acid cycle oxidizes organic fuel derived from pyruvate, generating ______ ATP, 2 NADH, and 1 FADH2 per turn.

1 Signup and view all the answers

The acetyl group of acetyl CoA joins the citric acid cycle by combining with ______, forming citrate.

oxaloacetate Signup and view all the answers

In plant cells, a ______ plate forms during cytokinesis.

cell Signup and view all the answers

In binary fission, the ______ replicates and the two daughter chromosomes actively move apart.

chromosome Signup and view all the answers

NADH and FADH2 produced by the citric acid cycle relay electrons extracted from food to the ______ transport chain.

electron Signup and view all the answers

Mitosis probably evolved from ______ fission.

binary Signup and view all the answers

The electron transport chain is in the ______ membrane of the mitochondrion.

inner Signup and view all the answers

Molecules present in the ______ control the progression to S and M phases.

cytoplasm Signup and view all the answers

Electron transfer in the chain causes proteins to pump ______ from the mitochondrial matrix to the intermembrane space.

H+ Signup and view all the answers

ATP synthase uses ______ flow of H+ to drive phosphorylation of ATP.

exergonic Signup and view all the answers

The G1 checkpoint is most important, and if it receives a go-ahead signal at this checkpoint, it usually completes all phases and ______.

divides Signup and view all the answers

Achondroplasia is a form of ______ caused by a rare dominant allele.

dwarfism Signup and view all the answers

Huntington’s disease is a degenerative disease of the ______ system.

nervous Signup and view all the answers

Many diseases have both genetic and ______ components.

environmental Signup and view all the answers

Genetic counselors can provide information to prospective parents concerned about a family history for a specific ______.

disease Signup and view all the answers

Amniocentesis involves testing the liquid that ______ the fetus.

bathes Signup and view all the answers

Phenylketonuria (PKU) is a recessively inherited ______.

disorder Signup and view all the answers

The Boveri-Sutton chromosome theory states that chromosomes are the basis for all ______ inheritance.

genetic Signup and view all the answers

Morgan showed that Mendelian inheritance has its physical basis in the behavior of ______.

chromosomes Signup and view all the answers

Study Notes

Apoptosis (Programmed Cell Death)

Components of infected, damaged cells or cells that reached the end of their functional lives are chopped and packaged into vesicles and digested by scavenger cells to prevent enzymes from leaking out of a dying cell and damaging neighboring cells.
Apoptosis in Caenorhabditis elegans (soil worm): signals activate a cascade of suicide proteins in cells programmed to die.
Ced-9, an apoptosis-inhibiting protein, is inactivated when a death signal is received, and the chief caspase in nematodes is called Ced-3.
In humans and other mammals, several pathways, including 15 caspases, can carry out apoptosis.

Cell Respiration

Energy flows into the ecosystem as sunlight and leaves as heat.
Photosynthesis generates O2 and organic molecules.
Cells use chemical energy stored in organic molecules to generate ATP.

Catabolic Pathways

Catabolic pathways release stored energy by breaking down complex molecules.
Electron transfer is important in these pathways.
Breakdown of organic molecules is exergonic.
Fermentation: partial degradation of sugars that occurs without O2.
Aerobic respiration: consumes organic molecules and O2, yields ATP.
Anaerobic respiration is similar to aerobic respiration but consumes compounds other than O2.

Citric Acid Cycle

In the presence of O2, pyruvate enters the mitochondrion, where oxidation of glucose is completed.
Pyruvate must be converted to acetyl Coenzyme A, which links glycolysis to the citric acid cycle.
The citric acid cycle completes the breakdown of pyruvate to CO2.
The cycle oxidizes organic fuel derived from pyruvate, generating 1 ATP, 2 NADH, and 1 FADH2 per turn.

Oxidative Phosphorylation

NADH and FADH2 donate electrons to the electron transport chain, which powers ATP synthesis via oxidative phosphorylation.
Electron transport chain is in the inner membrane (cristae) of the mitochondrion.
Most of the components are proteins.
Electron transfer in the chain causes proteins to pump H+ from the mitochondrial matrix to the intermembrane space.
H+ moves back across the membrane, passing through the protein complex, ATP synthase.

Calvin Cycle

The Calvin cycle uses ATP and NADPH to reduce CO2 to sugar.
The Calvin cycle builds sugar from smaller molecules by using ADP and reducing power of electrons carried by NADPH.
Carbon enters the cycle as CO2 and leaves as a sugar, glyceraldehyde 3-phosphate (G3P).

Alternative Mechanisms

Photorespiration: a process that favors the Calvin cycle, but also consumes O2 and organic fuel and releases CO2 without producing ATP or sugar.

Cell Division

Mitosis: a type of cell division that results in two daughter cells with the same number of chromosomes as the parent cell.
Cytokinesis: the process of cytoplasmic division, which occurs differently in animal and plant cells.
Binary fission: a type of cell division found in prokaryotes.

Cell Cycle Regulation

The cell cycle is regulated by molecular control systems.
Cancer cells manage to escape usual controls.
Experiment conclusion: molecules present in the cytoplasm control the progression to S and M phases.
Cell cycle control system: similar to a clock, regulated by internal and external controls.

Genetic Disorders

Dominantly inherited disorders: caused by dominant alleles, such as achondroplasia and Huntington's disease.
Multifactorial disorders: have both genetic and environmental components, such as heart disease, diabetes, and cancer.
Genetic testing and counseling: can provide information to prospective parents concerned about a family history for a specific disease.

Linkage and Chromosomes

Boveri-Sutton chromosome theory: states that chromosomes are the basis for all genetic inheritance.
Morgan showed that Mendelian inheritance has its physical basis in the behavior of chromosomes.

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Description

Learn about programmed cell death, its mechanisms, and significance in preventing damage to neighboring cells. Explore apoptosis in Caenorhabditis elegans and the cascade of suicide proteins.