Eukaryotic cells pt2

What are mitochondria?

Organelles that produce ATP and are called the powerhouse of the cell

Why are mitochondria called the powerhouse of the cell?

Because they synthesize ATP which provides usable energy for the cell

What is ATP?

The usable energy currency of the cell

What is the main function of mitochondria?

To produce ATP for cellular energy

What are the main structural parts of a mitochondrion?

Outer membrane inner membrane intermembrane space cristae and matrix

What is the outer mitochondrial membrane?

The membrane surrounding the outside of the mitochondrion

What is the inner mitochondrial membrane?

The inner membrane that contains components of the electron transport chain

What is the intermembrane space?

The space between the outer and inner mitochondrial membranes

What are cristae?

Folds of the inner mitochondrial membrane

Why are cristae useful?

They increase the surface area of the inner mitochondrial membrane

What is the mitochondrial matrix?

The space enclosed by the inner mitochondrial membrane

What important system is found in the inner mitochondrial membrane?

The electron transport chain

What does ETC stand for?

Electron transport chain

What does the electron transport chain help produce?

ATP

What happens to energy released from food molecules during mitochondrial oxidation?

It is trapped in the form of ATP

What food molecules can provide energy for ATP production?

Glucose fatty acids and amino acids

What is oxidative phosphorylation?

The process in which energy released from oxidation is captured in the form of ATP

What is the basic energy pathway involving mitochondria?

Food molecules → oxidation → electron transport chain → ATP

What metabolic pathways occur in the mitochondrial matrix according to the slides?

TCA cycle fatty acid oxidation and ketone body formation

Where does the TCA cycle occur?

In the mitochondrial matrix

Where does fatty acid oxidation occur according to the mitochondrial slide?

In the mitochondrial matrix

Where does ketone body formation occur?

In the mitochondrial matrix

What is the TCA cycle?

A metabolic pathway that takes place in the mitochondrial matrix

What are ketone bodies?

Molecules formed during fat metabolism that can be used as an alternative energy source

Do mitochondria contain their own DNA?

Yes

What shape is mitochondrial DNA?

Circular

What does mitochondrial DNA produce?

Some mitochondrial membrane proteins

Do mitochondria contain ribosomes?

Yes

What do ribosomes do?

They make proteins

From which parent is mitochondrial DNA inherited?

The mother

What type of inheritance do mitochondrial diseases show according to the slides?

Maternal inheritance

What does maternal inheritance mean?

Inheritance from the mother

What is the connection between mitochondrial DNA and maternal inheritance?

Mitochondrial DNA is inherited from the mother so mitochondrial DNA diseases can show maternal inheritance

What is cytochrome C?

A mitochondrial protein that can initiate programmed cell death

What process can cytochrome C initiate?

Apoptosis

What is apoptosis?

Programmed cell death

What is the relationship between mitochondria and apoptosis?

Cytochrome C from mitochondria can initiate apoptosis

What ion can mitochondria temporarily store?

Calcium

How do mitochondria contribute to calcium homeostasis?

They can temporarily store calcium

What is homeostasis?

Maintaining stable internal conditions

What is calcium homeostasis?

Maintaining balanced calcium levels in the cell

What can happen when genetic disorders affect mitochondria?

Mitochondrial enzymes can have abnormal structure or function and oxidative phosphorylation may not happen properly

Why can mitochondrial genetic disorders cause disease?

Because abnormal mitochondrial enzymes can interfere with oxidative phosphorylation

What is muscle atrophy?

Loss or shrinking of muscle tissue

What muscular problem can mitochondrial disorders cause?

Muscle atrophy

What heart problem can mitochondrial disorders cause?

Abnormal heartbeats

What does CNS stand for?

Central nervous system

What structures make up the CNS?

Brain and spinal cord

What nervous system problem can mitochondrial disorders cause?

CNS degeneration

What does CNS degeneration mean?

Deterioration or damage of the central nervous system

What does renal mean?

Related to the kidneys

What kidney problem can mitochondrial disorders cause?

Renal damage

What symptoms are listed for mitochondrial disorders?

Muscle atrophy abnormal heartbeats CNS degeneration and renal damage

What are lysosomes?

Membrane-bound vesicles containing digestive enzymes

What is a vesicle?

A small membrane-bound sac

What is the main function of lysosomes?

To digest and degrade cellular material and other substances

What type of enzymes do lysosomes contain?

Hydrolytic enzymes called hydrolases

What are hydrolases?

Enzymes that digest or degrade molecules

What can lysosomal hydrolases digest?

Proteins carbohydrates and nucleic acids

Where are lysosomal hydrolases made?

In the endoplasmic reticulum

What happens to lysosomal hydrolases in the Golgi apparatus?

They receive an M6P tag

What does M6P stand for?

Mannose-6-phosphate

What is the purpose of the M6P tag?

It directs hydrolases to lysosomes

What is the pathway of lysosomal hydrolases?

ER → Golgi → M6P tag → lysosome

What does the ER do in the lysosomal enzyme pathway?

It makes the hydrolases

What does the Golgi do in the lysosomal enzyme pathway?

It gives the hydrolases an M6P tag

Where do M6P-tagged hydrolases go?

To lysosomes

What is the approximate pH of the cytosol?

7.4

What is the approximate pH inside a lysosome?

4.8

Is the inside of a lysosome acidic or basic?

Acidic

Why is the acidic environment of lysosomes important?

Lysosomal hydrolases require an acidic pH to work

What is cytosol?

The fluid portion inside the cell

What types of cellular material can enter lysosomes for breakdown?

Cell debris damaged organelles and cytoplasmic material

What is autophagy?

The process in which a cell digests and recycles its own components

What does auto mean in autophagy?

Self

What does autophagy help remove?

Cell debris damaged organelles and cytoplasmic material

What happens to cell debris and damaged organelles during autophagy?

They enter lysosomes and are broken down

What happens during prolonged starvation?

The cell can digest its own components through autophagy to help generate energy

How can autophagy help a cell survive prolonged starvation?

The cell breaks down its own components to obtain useful materials and energy

What can happen to products produced by lysosomal breakdown?

They can return to the cytosol for reuse

Why can lysosomes be described as recycling organelles?

They break down cellular material and allow breakdown products to be reused

Can lysosomes digest material from outside the cell?

Yes

What external material can lysosomes digest?

Foreign particles brought into the cell

What happens if lysosomal hydrolytic enzymes are defective?

Materials cannot be broken down properly and can accumulate inside cells and tissues

What are lysosomal storage diseases?

Inherited metabolic disorders caused by defects in lysosomal hydrolytic enzymes

Why are they called lysosomal storage diseases?

Because substances that should be degraded accumulate or become stored in cells

What substances can accumulate in lysosomal storage diseases?

Lipids and carbohydrates

What can excessive storage of substances eventually cause?

Permanent cellular and tissue damage

Which tissues and organs can be particularly affected by lysosomal storage diseases?

Brain peripheral nervous system liver spleen and bone marrow

What is the peripheral nervous system?

The nerves outside the brain and spinal cord

What is bone marrow?

Soft tissue inside bones where blood cells are produced

What is the basic pathway of a lysosomal storage disease?

Defective hydrolase → poor breakdown → substance accumulation → cellular and tissue damage

What are peroxisomes?

Organelles involved in oxidation of very-long-chain fatty acids plasmalogen synthesis and hydrogen peroxide handling

What type of fatty acids are oxidized by peroxisomes?

Very-long-chain fatty acids

What does VLCFA stand for?

Very-long-chain fatty acid

What do peroxisomes do to very-long-chain fatty acids?

They carry out their oxidation

What important phospholipid do peroxisomes synthesize?

Plasmalogen

What are plasmalogens?

Important phospholipids essential for myelin formation and brain function

Why are plasmalogens important?

They are essential for myelin formation and brain function

What is myelin?

An insulating covering around many nerve fibers