Cell Structure and Organelles

Study Notes

Control center of the cell
Contains most of the cell's genetic material (DNA)
Surrounded by a double membrane called the nuclear envelope
Has pores that allow molecules to pass through
Consists of:
- Nucleolus: site of ribosome synthesis
- Chromatin: complex of DNA and proteins
- Nuclear matrix: network of proteins and filaments

Jelly-like substance inside the cell membrane
Site of many metabolic processes, including:
- Protein synthesis
- Cell signaling
- Cell division
Composed of:
- Water (about 70%)
- Salts
- Sugars
- Amino acids
- Organelles (e.g. mitochondria, ribosomes)
Plays a key role in cellular processes, such as:
- Cell movement
- Muscle contraction
- Cell signaling

Thin, semi-permeable membrane surrounding the cell
Regulates what enters and leaves the cell
Composed of:
- Phospholipid bilayer: phospholipid molecules with hydrophilic heads and hydrophobic tails
- Embedded proteins: transport, signaling, and structural proteins
Functions:
- Controls the movement of molecules in and out of the cell
- Maintains cell shape and structure
- Provides protection and support

Process of cell division that results in two daughter cells with the same number of chromosomes as the parent cell
Consists of several stages:
1. Interphase: cell grows, replicates DNA, and prepares for cell division
2. Prophase: chromatin condenses, nuclear envelope breaks down, and spindle fibers form
3. Metaphase: chromosomes line up at the center of the cell
4. Anaphase: sister chromatids separate and move to opposite poles
5. Telophase: nuclear envelope reforms, and chromosomes uncoil
6. Cytokinesis: cytoplasm divides, and cell splits into two daughter cells

Process by which a cell becomes two or more cells
Types:
- Mitosis: results in two daughter cells with the same number of chromosomes as the parent cell
- Meiosis: results in four daughter cells with half the number of chromosomes as the parent cell (gametes)
Importance:
- Growth and development
- Tissue repair and replacement
- Formation of gametes for reproduction

Nucleus is the control center of the cell and contains most of the cell's genetic material (DNA)
Nuclear envelope is a double membrane that surrounds the nucleus and has pores that allow molecules to pass through
Nucleolus is the site of ribosome synthesis
Chromatin is a complex of DNA and proteins
Nuclear matrix is a network of proteins and filaments

Cytoplasm is a jelly-like substance that makes up about 70% of the cell's volume
It is the site of many metabolic processes, including protein synthesis, cell signaling, and cell division
Cytoplasm is composed of water, salts, sugars, amino acids, and organelles like mitochondria and ribosomes
It plays a key role in cellular processes, such as cell movement, muscle contraction, and cell signaling

Cell membrane is a thin, semi-permeable membrane that regulates what enters and leaves the cell
It is composed of a phospholipid bilayer with hydrophilic heads and hydrophobic tails and embedded proteins
The cell membrane controls the movement of molecules in and out of the cell, maintains cell shape and structure, and provides protection and support

Mitosis is the process of cell division that results in two daughter cells with the same number of chromosomes as the parent cell
It consists of several stages: interphase, prophase, metaphase, anaphase, telophase, and cytokinesis
Cell division is important for growth and development, tissue repair and replacement, and the formation of gametes for reproduction
There are two types of cell division: mitosis and meiosis, which results in four daughter cells with half the number of chromosomes as the parent cell