Biology Chapter: Cell and Organization Levels

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Questions and Answers

What is the primary function of mitosis?

Formation of spindle fibers

Growth and tissue repair (correct)

Production of haploid sex cells

Reduction of chromosome number

Which transport mechanism is characterized by the ingestion of large solid particles?

Diffusion

Phagocytosis (correct)

Endocytosis

Pinocytosis

Which of the following statements is true about meiosis?

It occurs only in somatic cells.

It divides the chromosome number in half. (correct)

It produces two identical daughter cells.

It involves a single round of cell division.

What is the role of the axon in nerve physiology?

Conveys action potential away from the cell body Signup and view all the answers

Which type of transport uses ATP to transport substances against their concentration gradient?

Primary active transport Signup and view all the answers

What occurs during the telophase of cell division?

Chromosomes disperse and the nuclear envelope reappears Signup and view all the answers

Which structure is responsible for detoxifying free radicals such as alcohol?

Peroxisome Signup and view all the answers

What is a characteristic of the cytoskeleton?

Acts as a framework for the cell Signup and view all the answers

What is the function of mitochondria in a cell?

To produce ATP Signup and view all the answers

Which part of the cell is primarily involved in the synthesis and transport of proteins?

Endoplasmic reticulum Signup and view all the answers

What type of cell fluid accounts for 60% of the total water in the body?

Protoplasm Signup and view all the answers

Which component of the cell membrane is hydrophilic?

Lipid heads Signup and view all the answers

Which structure surrounds and protects the nucleus of the cell?

Nuclear envelope Signup and view all the answers

What is the main role of lysosomes within the cell?

To digest unwanted substances Signup and view all the answers

Which type of fluid is found in the plasma?

Extracellular fluid Signup and view all the answers

What do proteins in the cell membrane NOT serve as?

Energy storage molecules Signup and view all the answers

Study Notes

Basic Biological Levels

Cells are the fundamental unit of life in all organisms.
The chemical level involves the combination of atoms forming molecules.
Molecules combine to form cells, which aggregate into tissues.
Tissues build organs, which further form organ systems.
Organ systems together comprise an organism.

Cellular Composition

Protoplasm is the substance filling the cell, with water being the most abundant component (60%).
Water distribution: 40% intracellular fluid (ICF), 20% extracellular fluid (ECF), composed of 5% plasma and 15% interstitial fluids.

Cell Structure

The cell membrane is the outer layer, characterized by:
- A bilayer of lipids, amphipathic nature with hydrophilic heads and hydrophobic tails.
- Semi-permeability allowing gas passage, specifically oxygen and carbon dioxide.
Cytoplasm acts as the inner environment, housing organelles and separating the nucleus from the membrane.

Nucleus and Genetic Material

The nucleus serves as the control center of the cell, containing DNA and surrounded by a nuclear envelope for protection.
The nucleolus is integral for ribosome production.

Organelles and Their Functions

Mitochondria are known as the powerhouse, generating ATP for energy.
Endoplasmic reticulum is crucial for protein and lipid synthesis:
- Rough ER creates protein vesicles.
- Smooth ER focuses on lipid synthesis and detoxification.
Golgi apparatus modifies and packages proteins from the rough ER.
Lysosomes contain hydrolase enzymes for digesting unwanted substances and damaged cells, instrumental in macrophages and neutrophils.

Cytoskeleton and Cell Movement

The cytoskeleton provides structural support.
Cilia facilitate movement over the cell surface, while flagella enable sperm mobility (longer than cilia).
Spindle fibers assist in chromosome separation during cell division, with centrioles being key to microtubule formation.

Cell Division Processes

Mitosis results in two daughter cells with the same chromosome number, essential for growth and tissue repair; somatic cells are diploid.
Meiosis creates four gametes, each with half the chromosome count; vital for sexual reproduction and results in haploid cells.

Phases of Cell Division (PMAT)

Prophase: Chromosomes pair and condense.
Metaphase: Chromosomes align at the midline.
Anaphase: Chromatids split and move towards opposite ends.
Telophase: Nucleus reappears, and cells begin to divide.

Cell Transport Mechanisms

Exocytosis expels cellular contents; endocytosis ingests materials, including subtypes:
- Phagocytosis for large solid particles (cell eating).
- Pinocytosis for small liquids (cell drinking).
Diffusion (passive transport) allows molecules to move from higher to lower concentration:
- Simple diffusion occurs spontaneously, while facilitated diffusion involves carrier proteins.
Osmosis entails water movement from higher to lower solute concentration.

Active Transport Mechanisms

Active diffusion moves substances against their concentration gradient, requiring energy:
- Primary active transport utilizes ATP directly.
- Secondary active transport derives energy from primary transport.

Nerve Physiology

Dendrites transmit action potentials towards the cell body, while axons relay them away.
The myelin sheath insulates electrical signals, with nodes of Ranvier enhancing conduction speed.
The axon hillock triggers generation of electrical signals.

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Description

Explore the fundamental concepts of biology with this quiz focusing on the basic unit of life, the cell, and its organization into tissues, organs, and systems. Understand the chemical levels including molecules, protoplasm, and the significance of water in cellular function. This quiz delves into the composition of cells and their roles in the hierarchy of life.