Animal, Plant and Human Cells

• Animal, human, and plant cells are the main types of cells discussed.

Cell Membrane

• A thin, flexible barrier surrounding the cell.
• It controls the passage of substances in and out of the cell.
• It helps to maintain the cell's shape and the internal environment.
• It is present in human, plant, and animal cells.

Cytoplasm

• Gel-like substance filling the space between the cell membrane and the nucleus.
• It supports and suspends cell organelles.
• It provides a medium for the transport of molecules within the cell.
• It is present in human, plant, and animal cells.

Mitochondria

• Performs cellular respiration, breaking down nutrients into energy the cell can use.
• Known as the "powerhouse" of the cell.
• Produces energy (ATP) through cellular respiration.
• It is present in human, plant, and animal cells.

Ribosomes

• Small structures composed of RNA and protein.
• They are the site of protein synthesis.
• It is present in human, plant, and animal cells.

Endoplasmic Reticulum (E.R.)

• A network of membranous tubules and sacs.
• Rough ER is studded with ribosomes and involved in protein synthesis and modification.
• Smooth ER lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium storage.
• It is present in human, plant, and animal cells.

Golgi Apparatus

• It is a stack of flattened, membranous sacs.
• It modifies, sorts, and packages proteins and lipids.
• The proteins and lipids are transported within or outside the cell.
• Is present in human, plant, and animal cells.

Lysosome

• Membrane-bound sacs containing digestive enzymes.
• They break down cellular waste, debris, and foreign substances.
• Present in animal cells

Vacuole

• Membrane-bound sacs that store water, nutrients, and waste products.
• They maintain cell turgor pressure (in plant cells).
• They store various substances.
• It is present in human, plant, and animal cells.

Cell Nucleus

• A membrane-bound organelle found in eukaryotic cells.
• It is often referred to as the "control center" of the cell.
• The nucleus stores genetic material, housing the cell's DNA, which contains the instructions for all cellular activities.
• It controls cellular activities, regulating gene expression, cell growth, division, and metabolism.
• It directs protein synthesis by transcribing DNA into RNA, which carries the genetic code to ribosomes for protein production.

Nuclear Envelope

• Double membrane surrounding the nucleus.
• Separates the inside of the nucleus from the cytoplasm.
• It protects the DNA.
• Regulates the passage of molecules in and out of the nucleus through nuclear pores.

Nucleoplasm

• Jelly-like substance within the nucleus.
• It suspends the chromosomes and nucleolus.
• It provides a medium for the transport of molecules within the nucleus.

Chromatin

• The complex of DNA and proteins that makes up chromosomes.
• Packages and organizes DNA to fit within the nucleus.
• Controls gene expression.

Nucleolus

• A dense structure within the nucleus.
• It is the site of ribosome production.

Differences between cells

• Animal cells have only a cell membrane, not a cell wall.
• Plant cells have cell walls.
• Plant cells have larger vacuoles.
• Animal cells have centrioles.

This material covers the basics of animal, human, and plant cells. It describes the cell membrane, cytoplasm, and the function of mitochondria for energy production. It also highlights the role of the ribosomes in protein synthesis.