Organelle

A highly organized intracellular structure that performs a specific (metabolic) function for the cell.

Cell

The basic structural and functional unit of living organisms.

Although cells have differences that reflect their specific functions in the body, what functions do they have in common?

Growing, reproducing, and responding to a stimulus are common functioning characteristics amongst all cells. All cells can maintain their boundaries, metabolize, digest nutrients, and dispose wastes.

Plasma membrane

external boundary of cell; regulates flow of materials into and out of the cell; site of cell signaling

Lysosome

contains digestive enzymes of many varieties; "suicide sac' of the cell

Mitochondria

scattered throughout the cell; major site of ATP synthesis

Microvilli

slender extensions of the plasma membrane that increase its surface area

Inclusions

stored glycogen granules, crystals, pigments, and so on

Golgi apparatus

membranous system consisting of flattened sacs and vesicles; packages protein for export

Nucleus

control center of the cell; necessary for cell division and cell life

Centrioles

two rod-shaped bodies near the nucleus; direct formation of the mitotic spindle

Nucleolus

dense, darkly staining nuclear body; packaging site for ribosomes

Microfilaments

contractile elements of the cytoskeleton

Rough ER or endroplasmic reticulum

membranous system; involved in intracellular transport of proteins and synthesis of membrane lipids

Ribosomes

attached to membrane systems or scattered in the cytoplasm; synthesize proteins

Chromatin or Chromatin threads

threadlike structure in the nucleus; contain genetic material (DNA)

Peroxisome

site of free radical detoxification

For each of the following cell types, list (a) one important structural characteristic observed in the laboratory, and (b) the function that the structure complements or ensures.

squamous epithelium
a.____________________________________
b.____________________________________

squamous epithelium tissue
a) flat shaped
b) good for layering and overlapping

For each of the following cell types, list (a) one important structural characteristic observed in the laboratory, and (b) the function that the structure complements or ensures.

sperm
a.____________________________________
b.____________________________________

sperm
a) flagella
b) allows the cell to be mobile

For each of the following cell types, list (a) one important structural characteristic observed in the laboratory, and (b) the function that the structure complements or ensures.

smooth muscle
a.____________________________________
b.____________________________________

smooth muscle
a) has a fusiform shape, elongated shape
b) allows the muscle to tense and relax

For each of the following cell types, list (a) one important structural characteristic observed in the laboratory, and (b) the function that the structure complements or ensures.

red blood cells
a.____________________________________
b.____________________________________

red blood cells
a) biconcave shape
b) allows more surface area for efficient gas transfer

What is the significance of the red blood cell being anucleate (without a nucleus)?

The red blood cell(RBC) does not have a nucleus. The lack of a nucleus enables the RBC to have more room to contain hemoglobin which increases its efficiency to carrying oxygen.

Red Blood Cell:
Did it ever have a nucleus? If so, when?

They did have a nucleus . When they are formed in the bone-marrow, they contain a nucleus, but when the become mature it is replaced by hemoglobin in order to carry more oxygen.

Of the four cells observed microscopically (squamous epithelial cells, red blood cells, smooth muscle cells, and sperm) which has the smallest diameter? ________ Which is longest? _________

smallest: RBC
longest: smooth muscle cell

Metaphase

Anaphase

Prophase

What is the importance of mitotic cell division?

The importance of mitotic cell division is to make a greater amount of cells for repair and growth while maintaining the same genetic makeup.

Division of the __1__ is referred to as mitosis. Cytokinesis is division of the __2__. The major structural difference between chromatin and chromosomes is that the latter are __3__. Chromosomes attach to the spindle fibers by undivided structures called __4__.

1. Nucleus
2. Cytoplasm
3. Coiled/Condensed/Shortened
4. Centromeres

If a cell undergoes mitosis but not cytokinesis, the product is __5__. The structure that acts as a scaffolding for chromosomal attachment and movement is called the __6__. __7__ is the period of cell life when the cell is not involved in division. Two cell populations in the body that do not routinely undergo cell division are __8__ and __9__.

5. A binucleate cell or multinucleated cell
6. Spindle
7. Interphase
8. Skeletal
9. Cardiac

Interphase

- Centrioles replicate

- DNA synthesis occurs

Prophase

- Chromatin coils and condenses, forming chromosomes

- The nuclear envelope fragments

- The mitotic spindle forms

- Chromosomes first appear to be duplex structures

- Chromosomal centromeres are attached to the kinetochore fibers

Metaphase

- Chromosomes line up in the center of the cell

Anaphase

- The chromosomes are v-shaped

Telophase

- Cleavage furrow forms

- The nuclear envelope re-forms

- Chromosomes stop moving toward the poles

Anaphase and Metaphase

- The nuclear envelope is absent

What is the physical advantage of the chromatin coiling and condensing to form short chromosomes at the onset of mitosis?

Short, compact bodies easier to manipulate during mitosis rather than long, thin chromatin threads.