key terms of term # 3

all living organisms are made up of cells

cell theory has 3 basic principles,
1. all organisms are composed of cells.
2. all cells come from pre-existing cells.
3. cells are smallest unit of life.

made up of cells: single-celled organisms with nuclei and many other organelles.

Responds to Environment: A light-sensitive “eye spot” allows Chlamydomonas to sense light and swim to it using its flagella. eyespot area name is PYRENOID.

Homeostasis: contractile vacuoles fill up with water and expel it to regulate cell’s water content

Reproduction: Nucleus of cell divides via mitosis to make extra nuclei needed for cell to reproduce (usually asexual)

Growth and Development:  Photosynthesis happens inside the cytoplasm (carbon dioxide is converted to compounds needed for growth)

Nutrition: Chlamydomonas absorb CO2 into the chloroplasts found in its cytoplasm. “Food” is synthesized via photosynthesis.

Metabolism: Cytoplasm contains enzymes that break down substances to release energy

Excretion: Oxygen, a by-product of photosynthesis, freely diffuses out through the cell membrane

made up of cells: single-celled organisms with nuclei and many other organelles.

Responds to Environment: Paramecium control beating of cilia to move in different directions in response to changes in environment

Homeostasis:
contractile vacuoles fill up with water and expel it to regulate cell’s water content

Reproduction: Nucleus of cell divides via mitosis to make extra nuclei needed for cell to reproduce

Growth and Development: The cell will enlarge until a maximum size, at which point it will divide

Nutrition: Paramecium consumes smaller organisms that are packaged into food vacuoles. “Food” is gradually digested and absorbed into the cytoplasm.

Metabolism: Cytoplasm contains enzymes that break down substances to release energy

Excretion: Waste products are excreted through anal pore.

Active Transport

1. movement of materials from low concentration to high concentration).
2. it requires ATP.

Passive Transport

1. movement of material from high concentration to low concentration)
2. It does not require ATP

There are three main types of passive transport:

1. Simple diffusion – movement of small molecules (e.g. O2, CO2, etc.) through plasma membrane.

2. Osmosis – movement of water molecules.

3. Facilitated diffusion – movement of large or charged molecules via membrane proteins (e.g. ions, sucrose, etc.)

Vesicular Transport:
Materials destined for secretion are transported around the cell in membranous containers called vesicles

materials pass through two places and are then secreted:
1.Endoplasmic Reticulum
2.Golgi Apparatus

Endoplasmic Reticulum:
Materials are transported from the ER when the membrane bulges and then buds to create a vesicle surrounding the material

Golgi Apparatus:
The vesicle is then transported to the Golgi apparatus and fuses to the internal (cis) face of the complex

BULK TRANSPORT:
The spontaneous breaking and reforming of the bilayer, allowing larger materials to enter or leave the cell without having to cross the membrane (this is an active process and requires ATP hydrolysis)

Mitosis is four steps process
1. prophase
2. metaphase
3. anaphase
4. telophase

A. PROPHASE:
1. nuclear membrane and nucleolus
begin's to fade.
2. dna condences to form chromosomes.
3. mitotic spindle begins to form and attach
to center of chromosomes

B. METAPHASE:
1. CHROMOSOMES MOVE TO CENTER OF CELL BY SPINDLE MICROTUBULUSES

D. TELOPHASE
1. the nuclear membrane begins to reform and chromosomes relax as DNA unwinds.

telophase is followed by cytokinesis(division of cytoplasm).
cytoplasm is divided into two equal parts means original cell is divided into two daughter cells.

C. ANAPHASE:
chromosomes is broken down into chromatids and taken to opposite directions.

Stargardt’s disease:
The progressive vision loss associated with Stargardt disease is caused by the death of photoreceptor cells in the central portion of the retina called the macula.