Cell Biology: Mitochondria and Organelles

Questions and Answers

What is the primary function of ATP produced by mitochondria?

Serving as the energy currency of the cell (correct)

Transporting nutrients within the cell

Facilitating cell division

Decomposing waste products

What distinguishes apoptosis from necrosis?

Apoptosis is a controlled process, whereas necrosis is chaotic and often caused by disease (correct)

Apoptosis results from viral infections, while necrosis does not

Apoptosis occurs only in rapidly dividing cells, while necrosis can affect any cell type

Apoptosis leads to the release of toxins, while necrosis promotes cell health

How do mitochondria inherit their DNA?

Exclusively from the mother (correct)

Through random genetic recombination

Exclusively from the father

From both parents equally

What is generated within the mitochondrial matrix?

Enzymes for the TCA cycle Signup and view all the answers

Which of the following is a function of the outer mitochondrial membrane?

Serving as a barrier between cytosol and mitochondria Signup and view all the answers

What role do cristae play in mitochondrial function?

Increasing the inner membrane surface area for ATP production Signup and view all the answers

Which process occurs in the inner mitochondrial membrane?

Electron transport chain activity Signup and view all the answers

What is the fate of mature mammalian red blood cells in relation to mitochondria?

They lack both a nucleus and mitochondria Signup and view all the answers

What does the term 'semi-autonomous' imply regarding mitochondria?

They can replicate independently of the nucleus Signup and view all the answers

Which protein is involved in heat production in mitochondria?

Thermogenin Signup and view all the answers

What phenomenon does the term 'proton motive force' refer to?

The potential energy generated by proton pumping Signup and view all the answers

Which of the following correctly describes necrosis?

Often caused by physical injury or disease Signup and view all the answers

What is a major characteristic of mitochondrial DNA?

It is circular and resembles bacterial DNA Signup and view all the answers

What is the primary reason liver cells, or hepatocytes, have a high number of mitochondria?

To meet high energy demands for metabolic processes Signup and view all the answers

Study Notes

Mitochondria Overview

"Mitochondria" derives from Greek, meaning grain-like; singular form is "mitochondrion".
Known as the powerhouse of the cell, crucial for energy production.

Mitochondrial Structure

Double membrane-bound organelle with an outer and inner membrane.
Intermembrane space exists between the two membranes; inner membrane has folds called cristae.
The interior is called the matrix, housing enzymes for the TCA cycle.

Energy Production

Primary function is to produce ATP (adenosine triphosphate), the energy currency of cells.
ATP synthesis occurs via the electron transport chain, also known as oxidative phosphorylation.
Protons are pumped from the matrix into the intermembrane space, creating proton motive force that drives ATP synthase.

Mitochondrial Functions

Besides ATP production, mitochondria play roles in:
- Apoptosis initiation (programmed cell death).
- Cell signaling and differentiation.
- Regulation of the cell cycle and growth.
- Heat production via the protein thermogenin in brown adipose tissue.
- Heme synthesis.

Genetic Information

Mitochondria contain their own circular DNA, resembling bacterial DNA.
Mitochondrial DNA is inherited exclusively from the mother through the ovum during fertilization.

Cell Types and Mitochondrial Content

Mature mammalian red blood cells lack both a nucleus and mitochondria.
Hepatocytes (liver cells) contain over 2,000 mitochondria per cell to meet high energy demands.

Distinction Between Apoptosis and Necrosis

Apoptosis: Controlled, healthy cell death process, enabling regeneration.
Necrosis: Pathological cell death resulting from disease or injury, considered "cell murder".

Key Takeaways

Dysfunctional mitochondria can lead to diseases passed from mother to offspring, as paternal mitochondria do not contribute to the zygote.
Mitochondria are essential not only for energy but also for maintaining cellular health and functions.

Description

This quiz explores key concepts about mitochondria and other important organelles in the cell. Understand the functions, structures, and roles of mitochondria, lysosomes, Golgi apparatus, and more. Test your knowledge of cellular components and their significance in biology.