Cell Biology Overview

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Questions and Answers

What is the role of messenger RNA (mRNA) in the central dogma of biology?

It stores genetic information permanently.

It carries DNA from the nucleus to the ribosomes. (correct)

It translates RNA into DNA.

It transports amino acids to the ribosomes for protein synthesis.

Which statement best reflects the characteristics of viruses in relation to the central dogma?

Viruses are capable of carrying out the central dogma independently.

Viruses cannot replicate without infecting a host cell. (correct)

All viruses contain both DNA and RNA to function.

Viruses are considered living organisms due to their genetic material.

In the context of cell theory, which statement is incorrect?

A cell is the smallest unit of life.

All cells arise from other living cells.

DNA provides the instructions necessary for protein synthesis.

Cells can spontaneously generate from non-living matter. (correct)

How does the process of epigenetics differ from traditional gene expression?

Epigenetics refers to heritable changes in gene expression without altering the DNA sequence. Signup and view all the answers

What distinguishes prokaryotic from eukaryotic DNA?

Prokaryotic DNA lacks histones whereas eukaryotic DNA contains histones. Signup and view all the answers

Which option best describes the function of the nucleolus in eukaryotic cells?

It is the site of ribosome production. Signup and view all the answers

Which type of microscopy allows visualization of live cells with a glow around their edges?

Phase-contrast Microscopy Signup and view all the answers

Which bond type exhibits the weakest strength in an aqueous environment?

Van der Waals Forces Signup and view all the answers

What is the primary purpose of using model organisms such as 'Drosophila Melanogaster' in scientific research?

To understand the genetic basis of sex chromosomes. Signup and view all the answers

Which structure acts as a 'security guard' for the cell?

Plasma Membrane Signup and view all the answers

What is the characteristic feature of HeLa cells in laboratory studies?

They can grow indefinitely and are immortalized. Signup and view all the answers

Which macromolecule is primarily synthesized in the ribosomes?

Proteins Signup and view all the answers

Which type of cells are considered prokaryotes?

Escherichia coli cells Signup and view all the answers

In the context of cellular components, what does the term 'Hayflick Limit' refer to?

The maximum number of divisions a cell can undergo before stopping. Signup and view all the answers

Which organelle is primarily responsible for the synthesis of ATP in eukaryotic cells?

Mitochondria Signup and view all the answers

Study Notes

Cells and Their Environment

Cells undergo constant changes via endocytosis and exocytosis.
Familiarity with cell theory is beneficial but not memorization.
Microscopes play a critical role in cellular studies.
Knowledge of model organisms and their suitability for research is important.
Distinguish between prokaryotic and eukaryotic DNA.

Central Dogma of Biology

Process: DNA → RNA (transcription) → Protein (translation).
Central dogma failure indicates cell death.
Proteins drive cellular function and are products of gene expression.
DNA serves as information storage, RNA as a temporary message, and proteins as functional units.

Cell Theory

Cells are the basic unit of life.
New cells arise from pre-existing ones (principle of heritability).
DNA encodes protein synthesis, governing cellular activities.

Diversity of Cells

Various cell types exist (e.g., neurons, blood cells) without needing to memorize all types.
Viruses deviate from the central dogma; can be DNA or RNA and are viewed as inactive outside host cells.

Epigenetics

Gene expression can be influenced by factors beyond DNA, illustrated by examples like A Lemato.

Cell and Molecule Sizes

Most cells range in micrometers; some, like muscle cells, may extend to 1 meter.
Molecules and small bacteria usually exist at the nanometer scale.

Microscopes

Several microscopy techniques are used, each with unique capabilities:
- Light Microscopy: Bright field shows cell outlines; phase contrast reveals living cells.
- Confocal Microscopy: Uses lasers for depth focus; combines optical sections into 3D images.
- Fluorescence Microscopy: Uses fluorescent dyes for visualization of specific proteins; requires light.
- Transmission Electron Microscopy: Shoots electrons to create high-res images; operates at nanometer scale.

Prokaryotes vs. Eukaryotes

Eukaryotic Structures:
- Nucleus: DNA storage and site of ribosome production (nucleolus).
- Ribosomes: Translation sites for protein synthesis.
- Mitochondria: ATP production powerhouse.
- Endoplasmic Reticulum (RER/SER): Protein transport and lipid synthesis respectively.
- Golgi Apparatus: Packages substances into vesicles.
- Lysosomes: Involved in waste management.
Prokaryotic Structures:
- Nucleoid: Location of free-floating DNA.

Model Organisms

E. coli (Escherichia coli): Entire genome known; prokaryote.
Yeast (Saccharomyces cerevisiae): Small, easily manipulated, complete genome sequenced.
Arabidopsis thaliana: Plant model with known complete DNA sequence; fast reproduction.
Drosophila melanogaster: Well-characterized DNA; sex chromosomes identified.
C. elegans: Fully mapped brain used for drug reaction studies.
Danio rerio (Zebrafish): Transparent during early development for organ studies.
Mus musculus (Mice): Close relation to humans; behavioral research.
Homo sapiens (Humans): Utilized in clinical trials.

Cell Cultures

Cells can be cultured in laboratory settings:
- Primary Cell Culture: Directly isolated from living organisms; subject to the Hayflick limit.
- Immortalized Cell Lines: Transformed cells (e.g., HeLa cells) can replicate indefinitely, useful for research.

Chemical Components of Cells

Bond Strength in Aqueous Environments: Covalent > Ionic > Hydrogen > Van der Waals.
Covalent Bonds: Represent "molecular marriage"; the strongest.
Ionic Bonds: Similar to "molecular dating"; weaker than covalent.
Hydrogen Bonds: Hold water molecules together.

Macromolecules

Involves polymerization, the process of monomers forming larger structures.

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Description

Explore the essentials of cell biology, including the processes of endocytosis and exocytosis, the central dogma of biology, and the principles of cell theory. This quiz will test your understanding of cellular functions and the diversity of cell types. Perfect for anyone looking to deepen their knowledge in biological sciences.