Cytology and the Cell Cycle Overview

These flashcards cover key concepts from the lecture on cytology and the cell cycle, providing a comprehensive review for exam preparation.

What is Cytology?

The study of cells.

What does cell theory state?

1) The cell is the basic unit of life; 2) Body activity depends on the activity of cells; 3) Cell activity is dictated by internal cell structure; 4) Reproduction ultimately depends on cells.

How many types of human cells exist?

There are over 200 types of human cells, each with unique characteristics.

What shape are nerve cells?

Irregular.

What shape are red blood cells?

Biconcave discs.

What is the shape of kidney tubule cells?

Cube-shaped.

What is the shape of intestinal lining cells?

Column-shaped.

What is the shape of cartilage cells?

Spherical.

What is the shape of skeletal muscle cells?

Cylindrical.

What are the three basic parts of human cells?

1) Plasma membrane, 2) Cytoplasm, 3) Nucleus.

What is the plasma membrane?

A flexible outer boundary of the cell.

What does cytoplasm contain?

Intracellular fluid containing organelles.

What is the role of the nucleus?

It acts as the control center of the cell.

What is the structure of the plasma membrane?

A bimolecular layer of lipids and proteins in a constantly changing fluid mosaic.

What are the main components of the lipid bilayer?

Phospholipids, glycolipids, and cholesterol.

What is the function of membrane proteins?

They act as receptors, gates, pumps, enzymes, anchors, and provide cell recognition.

What does it mean for a membrane to be semipermeable?

It selectively allows certain substances to pass through.

What can readily pass through the plasma membrane?

Most small and lipid-soluble substances.

What cannot readily pass through the plasma membrane?

Most large and water-soluble substances.

What does interstitial fluid refer to?

The extracellular fluid that surrounds cells.

What is the fluid mosaic model?

It describes the plasma membrane structure, consisting of phospholipids with hydrophilic heads and hydrophobic tails embedded with proteins.

What do carbohydrates do in the fluid mosaic model?

They attach to the outer surface of the membrane.

What are membrane junctions?

Cell-to-cell connections that include tight junctions, desmosomes, and gap junctions.

What is a tight junction?

It prevents fluids and most molecules from moving between cells.

What is a desmosome?

It anchors cells together but allows for some movement.

What is a gap junction?

It allows ions or small molecules to pass from cell to cell through pores.

What are the two ways to cross the plasma membrane?

Passive transport and active transport.

What is passive transport?

Movement along a concentration gradient that does not require chemical energy.

What is active transport?

Movement against a concentration gradient that requires chemical energy (ATP).

Define simple diffusion.

Spontaneous movement of molecules from high to low concentration.

What is osmosis?

Diffusion of water across a membrane through aquaporin protein channels or the lipid bilayer.

What is an isotonic solution?

A solution where solute concentration is the same on both sides of the membrane.

What happens in a hypotonic solution?

Water moves into the cell, potentially causing it to burst.

What happens in a hypertonic solution?

Water moves out of the cell, causing it to shrink.

What is facilitated diffusion?

Movement of molecules across a membrane through a channel or carrier protein.

What is vesicular transport?

A type of active transport where macromolecules are brought into or out of a cell using a vesicle.

Define metabolism.

Chemical reactions within a cell.

What is catabolism?

The process of breaking down larger substances into simpler ones.

What is anabolism?

The process of forming complex substances from simpler ones, requiring energy.

What do chemical reactions involve?

Changes in the position of electrons surrounding atoms' nuclei.

What is the pH scale?

It measures the amount of free Hydrogen ions in a solution.

What is considered a neutral pH?

A pH of 7.

Why is pH important for metabolism?

Chemical reactions within cells require specific pH conditions for optimal function.

What does cytoplasm refer to?

Everything within the cell membrane excluding the nucleus.

What is cytosol?

The fluid within the cell membrane excluding the nucleus and organelles.

What are organelles?

Small structures in the cytoplasm with specific structures and functions.

What is the role of the endoplasmic reticulum (ER)?

A system of membranes important in protein and lipid synthesis.

What distinguishes rough ER from smooth ER?

Rough ER is studded with ribosomes; smooth ER is not.

What is the function of ribosomes?

They produce proteins.

What does the Golgi complex do?

Processes, packages, and distributes molecules about or from the cell.

What is the function of a lysosome?

Contains digestive enzymes for breaking down macromolecules.

What is a peroxisome?

Membrane-bound sac containing enzymes to detoxify harmful substances.

What is a mitochondrion responsible for?

Producing ATP molecules during aerobic cellular respiration.

What happens when oxygen runs out in a cell?

Energy is produced solely by anaerobic energy production.

What is the cytoskeleton?

The internal framework of the cell consisting of filaments.

What are microtubules?

The largest type of filament in the cytoskeleton.

What is the function of cilia?

To move substances across the cell surface.

What is the function of flagella?

To propel whole cells.

What do centrioles do?

Organize chromosomes during cell division.

What is the nucleus?

Contains chromatin (DNA and associated proteins) and nucleoplasm fluid.

What is the nucleolus?

Produces ribosomal (protein-producing) subunits.

How long does the G1 phase of the cell cycle take?

6 to 8 hours, involving normal cell functions.

What occurs during the S phase of the cell cycle?

DNA replication and synthesis of histones.

What occurs during the G2 phase of the cell cycle?

Protein synthesis and cell growth in preparation for division.

What are the stages of mitosis?

Prophase, Metaphase, Anaphase, Telophase.

What is cytokinesis?

The division of the cytoplasm into two daughter cells.

How long do cells typically spend in mitosis?

2 to 5 hours.

What is the collective term for stages G1, S, and G2?

Interphase.

What is the main purpose of the cell cycle?

To allow new cells to be made continuously for growth and repair.

What type of cells undergo mitosis?

Somatic cells.

What type of cells undergo meiosis?

Sex cells.