1.1 & 1.2 MCAT Concept Checks - Ch.1

The Cell Theory

1. all living things are made of cells

2. cell is the basic functional unit of life

3. all cells arise from pre-existing cells

4. genetic info is carried in the form of DNA and passed from parent to daughter cell

function of the Nucleus

stores genetic info

site of transcription

function of Mitochondria

involved in ATP production and apoptosis

function of Lysosomes

break down molecules ingested through endocytosis and cellular waste products;

can also be involved in apoptosis

function of RER

synthesizes proteins destined for secretion

function of SER

involved in lipid synthesis and detoxification

function of Golgi apparatus

packages, modifies, and distributes cellular products

function of Peroxisomes

break down very long chain fatty acids

synthesize lipids

contribute to the pentose phosphate pathway

A child is diagnosed with an enzyme deficiency that prevents the production of hydrogen peroxide. What would the likely outcome be of such a deficiency?

Peroxisomes are dependent on hydrogen peroxide for their functions, so an enzyme deficiency that results in an inability to form hydrogen peroxide would likely result in an inability to digest very long chain fatty acids. These fatty acids would build up in peroxisomes until most of the cellular contents were displaced by oversized peroxisomes. This would ultimately result in cell death.

What is the predominant protein in microfilaments?

actin

What is the predominant protein in microtubules?

tubulin

What is the predominant protein in intermediate filaments?

differ by cell type, but include keratin and desmin

How do the cytoskeletal structures of centrioles and flagella differ?

CENTRIOLES: consist of 9 triplets of microtubules around a hollow center.

FLAGELLA: consist of 9 doublets on outside w/ 2 microtubules on inside.

Classify each of the following cells as epithelial cells or connective tissue:

Fibroblasts, which produce collagen in a number of organs:

Endothelial cells, which line blood vessels:

Alpha-cells, which produce glucagon in the pancreas:

Chondroblasts, which produce cartilage:

Osteoblasts, which produce osteoid, the material that hardens into bone:

EPITHELIAL CELLS: Endothelial cells and Alpha-cells

CONNECTIVE TISSUE CELLS: Fibroblasts, osteoblasts, & chondroblasts