Biology Chapter 3: Cellular Organization

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Questions and Answers

What is the primary function of mitochondria in cells?

Lipid storage

ATP synthesis (correct)

Protein synthesis

DNA replication

Which structure in the mitochondria increases the internal surface area?

Outer membrane

Cristae (correct)

Centrosome

Matrix

What is the role of the solvent in a solution?

It is the substance that solutes dissolve into. (correct)

It is the substance being dissolved.

It is the dissolved particles in the solution.

It is the part of the solution that remains unchanged.

Which factor does NOT influence diffusion rates?

Alkalinity of the solution Signup and view all the answers

During glycolysis, what are glucose molecules broken down into?

Pyruvate Signup and view all the answers

What characterizes facilitated diffusion?

It uses a carrier protein for transport. Signup and view all the answers

What is produced during the citric acid cycle within mitochondria?

Carbon dioxide and ATP Signup and view all the answers

What is the diameter of microtubules compared to other cytoskeleton elements?

25 nm Signup and view all the answers

What occurs during osmosis in relation to water concentration?

Water moves from higher to lower concentration areas. Signup and view all the answers

What type of protein is primarily found in microfilaments?

Actin Signup and view all the answers

Which term describes the concentration of solutes in a solution?

Osmolarity Signup and view all the answers

In a hypertonic solution, what effect does it have on animal cells?

Cells lose water and crenate. Signup and view all the answers

What do centrioles consist of?

Short microtubules Signup and view all the answers

What is one of the main principles of cell theory?

All new cells come from the division of pre-existing cells. Signup and view all the answers

Which of the following structures provides strength and flexibility to the cell's cytoplasm?

Cytoskeleton Signup and view all the answers

What describes the process of filtration in biological systems?

It involves a pressure gradient. Signup and view all the answers

What process describes the gradual specialization of cells after fertilization?

Differentiation Signup and view all the answers

Which of the following statements about active transport is true?

It requires energy to move substances against their concentration gradient. Signup and view all the answers

What is the term used for the fluid component of the cytoplasm?

Cytosol Signup and view all the answers

What separates the cell contents from the extracellular fluid?

Plasma membrane Signup and view all the answers

Which scientists contributed to the development of cell theory?

Schleiden, Schwann, and Virchow Signup and view all the answers

Why do daughter cells begin to develop specialized characteristics?

As a result of cytoplasmic differences at fertilization. Signup and view all the answers

What is the primary component of the cytoplasm?

Proteins Signup and view all the answers

What is the primary function of nucleoli within the cell nucleus?

To synthesize ribosomal RNA Signup and view all the answers

What is the extracellular fluid also known as?

Interstitial fluid Signup and view all the answers

Which component is formed when DNA strands are coiled around histones?

Nucleosomes Signup and view all the answers

What distinguishes RNA from DNA regarding its structure?

RNA contains uracil instead of thymine Signup and view all the answers

What regulates the movement of ions and small molecules across the nuclear envelope?

Nuclear pores Signup and view all the answers

What is the role of the nuclear matrix found within nucleoplasm?

To provide structural support and regulate genetic activity Signup and view all the answers

How many chromosomes are present in human cells?

46 Signup and view all the answers

What feature of RNA allows it to function outside the nucleus?

It is not confined to the nucleus Signup and view all the answers

Which biological macromolecules are involved in protein synthesis?

DNA, enzymes, and three types of RNA Signup and view all the answers

What role does messenger RNA (mRNA) play in protein synthesis?

It takes the coded message of DNA to the cytoplasm for polypeptide construction. Signup and view all the answers

During transcription, what causes RNA polymerase to stop transcribing DNA?

Reaching a terminator sequence. Signup and view all the answers

What function do spliceosomes serve in the processing of mRNA?

They remove introns and join exons. Signup and view all the answers

What is the first step in the translation process of protein synthesis?

The ribosome subunits bind to mRNA near the start codon. Signup and view all the answers

Which statement correctly describes the role of tRNA during translation?

tRNA carries amino acids and has anticodons for matching with codons. Signup and view all the answers

What is the significance of the start codon in protein synthesis?

It instructs the ribosome where to initiate translation. Signup and view all the answers

Which step follows the binding of the second tRNA to the ribosome during chain elongation?

A peptide bond forms between the first and second amino acids. Signup and view all the answers

Which of the following describes introns in the context of mRNA processing?

They are removed from the mRNA transcript during processing. Signup and view all the answers

Study Notes

Cell Theory and Cellular Organization

Developed by Schleiden, Schwann, and Virchow; fundamental framework for understanding cells.
All living organisms are composed of cells, which are essential for physiological functions.
New cells arise from the division of existing cells, emphasizing a cyclic nature.
Complementarity of form and function signifies that cell structure dictates functionality.
Cytology is the specialized study of cells.

Differentiation

Cells arise from the fertilized ovum, which contains genetic potential for diverse cell types.
Cellular division leads to specialized functions as cells differentiate, creating tissues.

Components of Cells

The plasma membrane separates cell contents from extracellular fluid, maintaining homeostasis.
Cytoplasm contains organelles and cytosol; it’s thicker than extracellular fluid and rich in proteins.

Diffusion and Osmosis

Solute movement (diffusion) is influenced by distance, size, temperature, and concentration gradient.
Facilitated diffusion requires carrier proteins, does not demand ATP.
Osmosis is the movement of water from higher to lower concentration areas, influenced by solute concentrations.

Tonicity Effects on Cells

Isotonic solutions maintain cell shape as solute concentrations are equal inside and outside the cell.
Hypertonic solutions cause cells to lose water and undergo crenation.
Hypotonic solutions lead to water influx, potentially causing cells to lyse.

Active Processes

Active processes require cellular energy (ATP) for transport mechanisms.

Mitochondria

Mitochondria serve as the energy factories of the cell, producing ATP through aerobic respiration.
The process involves glycolysis in the cytoplasm, the citric acid cycle in the mitochondrial matrix, and the electron transport system in the cristae.

Non-Membranous Organelles

The cytoskeleton consists of microfilaments, intermediate filaments, and microtubules, providing cell structure and strength.
Centrioles are cylindrical microtubule structures important for cell division.
Nucleoplasm includes the nuclear matrix and various biomolecules aiding genetic regulation.

DNA and Protein Synthesis

DNA retains hereditary information; it coils into chromatin and chromosomes during cell division.
RNA differences: consists of ribose sugar, uses uracil instead of thymine, is single-stranded, and is not confined to the nucleus.

Types of RNA

Ribosomal RNA (rRNA) forms ribosome structures for protein synthesis.
Messenger RNA (mRNA) conveys genetic instructions from DNA to ribosomes.
Transfer RNA (tRNA) carries amino acids to ribosomes and checks codon-anticodon pairing.

Protein Formation Steps

Transcription occurs when RNA polymerase synthesizes RNA from DNA templates.
mRNA is processed by splicing out introns before exiting the nucleus.
Translation in the cytoplasm involves initiation at the start codon (AUG), elongation through tRNA binding, and formation of peptide bonds.

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Description

Explore Chapter Three of your biology textbook, focusing on the cellular level of organization. This chapter covers essential concepts such as cell theory, the building blocks of life, and the relationship between form and function in cells.