Biology: Cell structure and transport

Anton van Leeuwenhoek

created the first microscope in 1650

Robert Hooke

First to onserve cells (looked at cork cell walls) in 1675

Schleiden

all plants are made of cells

Schwann

all animals are made of cells

Virchow

all cells come from pre existing cells

Cell Theory

1. All living organisms made of cells

2. Cells are the basic unit of structure and function

3. New cells arise only from pre existing cells

Differentiation

cells variety of structures and functions

Cell/ Plasma Membrane

Separates the cell from the environment

Semi permeable

Most are made of phospholipids, proteins and carbohydrates

Nucleus

Houses DNA and instructions for proteins

Prokaryotes

Before Nucleus

Do not have membrane bound organelles

Eukaryotes

True Nucleus

Membrane bound nucleus and organelles

Nucleolus

Center of the nucleus

Makes ribosomes

Ribosomes

Synthesizes proteins

Free in the cytoplasm and attached to the rough ER

Endoplasmic Reticulum

System of folded membranes and tunnels running throughout the cell

Rough ER

involved in the manufacture of proteins to be exported from the cell

Smooth ER

makes phospholipids

detoxification of poisons and alcohol

Mitochondria

Site of cellular respiration

Cellular Respiration: process in which glucose molecules are broken down to produce ATP

ATP: universal source of energy for living organisms

Golgi Apparatus

Stack of flattened membranes where proteins are modified, packaged, and folded for export from the cell

Lysosomes

Small vesicles full of digestive enzymes

Destroy waste, break down bacteria, digest food particles

Programed cell death = apoptosis

Only animal cells

Cytoskeleton

Microtubules and microfilaments

Form a framework within the cell

Transport material through the cell

Cilia

Short and present in high abundance

In unicellular organisms used for locomotion

Used to sweep particles in multicellular organisms

Flagella

long and present in low abundance

Locomotion in both uni and multicellular

Centrioles

Made of bundles of microtubules which aid in cell division

Only in animal cells

Centrosomes: a pair of centrioles

Cell wall

Rigid covering outside the cell wall

Gives stability to plant cells

Composed of cellulose

Only in plant cells

Chloroplasts

Site of photosynthesis(contains chlorophyll)

Double membranes

Inner membranes = thylakoid, folded into stacks

Central Vacuole

Can occupy 90% of cell volume

Stores water, waste, digestive enzymes

Turgor pressure

Pressure exerted by fluid in a cell

Presses the cell membrane against the cell wall

Gives plant tissue rigidity

Cytosol

intracellular fluid that is present inside the cells

Cytoplasm

EVERYTHING inside the cell