Cells

Two types of cells:

Eukaryotic and Prokaryotic

Eukaryotic Cell

• has a true nucleus

• has a nuclear membrane with well-defined chromosomes

• has membrane-bound organelles

• may be single-celled or multicellular

• ex: cells of plants, animals, and fungi

Prokaryotic Cell

• nucleus is not distinct

• DNA is not organized into chromosomes

• lacks membrane-bound organelles

• are usually unicellular organisms

• example is bacteria

Plasma Membrane

• cell’s defining boundary

• provides a barrier and contains transport and signaling systems

Nucleus

• the cell’s information center

• the place where almost all DNA replication and RNA synthesis occur.

Functions of the Nucleus

• cell division and regulation of the gene expression

Nucleolus

is the site for the synthesis of the RNA, making up the ribosome.

Mitochondria

• the powerhouse of the cell / the power generator

• surrounded by a double membrane called cristae

• contains its own DNA, which is a circular double-stranded structure

Function of the Mitochondria

energy production through metabolism

Ribosomes

the protein and RNA complex is responsible for protein synthesis

Endoplasmic Reticulum

the transport network for molecules and it is directly connected to the outer membrane of the nucleus in a eukaryotic cell

Rough Endoplasmic Reticulum

• covered with ribosomes (causing the “rough” appearance) which are synthesizing proteins for secretion or localization in membranes.

Smooth Endoplasmic Reticulum

a site for the synthesis and metabolism of lipids

Golgi Apparatus

• a system of membranes, made of flattened sac-like structures called cisternae

Function of the Golgi Apparatus

• process and package the macromolecules

• works closely with the smooth ER to modify proteins for export by the cell

Lysosomes

• contains a digestive enzyme

• a membrane-bound organelle that is responsible for degrading proteins and membranes in the cell

• pH of the lysosome is acidic

Function of the Lysosome

digestion, autophagy, autolysis

Vacuoles

membrane-surrounded “bags” that contain water and storage materials in plants.

Peroxisomes or Microbodies

produce and degrade hydrogen peroxide, a toxic compound that can be produced during metabolism.

Cell Wall

plants have a rigid cell wall in addition to their cell membranes

Cytoplasm

enclosed by the plasma membrane, the liquid portion is called cytosol, and it houses the membranous organelles

Cytoskeleton

arrays of protein filaments in the cytosol. Gives the cell its shape and provides a basis for movement.

• ex: microtubules and microfilaments.

Water comprises about ___ of the cell volume

60%

The Human body has ____of water

60%

The Human body has ___ proteins

15%

The Human body has ___ lipids

15%

The Human body has ___ carbohydrates

2%

The Human body has ___ minerals

8%

Carbohydrates

• composed of carbon, hydrogen, and oxygen

• sugars

Monosaccharides

glucose

Dissacharides

sucrose

Polysaccharides

glycogen, starch

Lipids

• fatty acids: building blocks of lipid

• ex: waxes, fats & oils, phospholipids, and streoids.

Proteins

made up of polymers of amino acids

Nucelic Acid

• DNA & RNA

• the “hereditary molecule”

• contains genes that code for a certain product

• DNA is translated into RNA, which is used to produce protein or other products.

Carbon

• is more abundant in living organisms than it is in the rest of the universe.

What makes Carbon special?

the ability of carbon to bond together to form long chains and rings.