Module 2

What is the basic unit of structure and function in the human body?

Cells are the basic unit of structure, and they work to maintain homeostasis inside the body.

Define differentiated.

Differentiated cells are cells with specialized characteristics and functions.

How do cells differ from one another?

Cells vary in shape, size, structures, and functions.

Name and describe the three major parts of every cell.

Nucleus - Contains genetic material and directs cell activities; Cytoplasm - Consists of organelles suspended in a liquid called cytosol; Cell membrane - Outer boundary of the cell.

Define organelle.

Any structure in the cell that has a specialized function.

What does ‘selectively permeable’ mean?

It regulates the entry and exit of substances and permits the cell to receive and respond to messages.

What is the cell membrane made of?

A phospholipid bilayer with embedded proteins, cholesterol, and carbohydrates.

What is the function of ribosomes?

Ribosomes are involved in protein synthesis and can be found scattered in the cytoplasm or bound to the rough endoplasmic reticulum.

What are the two types of endoplasmic reticulum and their functions?

Rough Endoplasmic Reticulum: Conducts protein synthesis; Smooth Endoplasmic Reticulum: Conducts lipid synthesis.

What is the function of vesicles?

They transport and store substances.

What are the functions of the Golgi apparatus?

It refines, packages, and delivers proteins made on the rough endoplasmic reticulum.

What are the functions of mitochondria?

Mitochondria house chemical reactions that extract energy from nutrients, producing ATP.

Define lysosomes, peroxisomes, and microfilaments.

Lysosomes contain enzymes that digest various substances; Peroxisomes contain enzymes that digest lipids and hydrogen peroxide; Microfilaments provide cellular movement.

What is the function of the nucleus?

It contains DNA that directs the activities of the cell.

Where is the nucleolus located and what is its function?

Located within the nucleus, it is the site of ribosome production.

What is the difference between the nucleus and the nucleolus?

The nucleus contains DNA and directs cell activities, while the nucleolus is responsible for making ribosomes.

Describe chromatin.

A thread-like structure composed of protein and DNA molecules that carries information for synthesizing proteins.

Distinguish between intracellular fluid and extracellular fluid.

Intracellular fluid is found inside the cell; extracellular fluid is found outside the cell.

What are passive processes in molecule movements?

Passive processes do not require cellular energy (ATP) and include diffusion, osmosis, facilitated diffusion, and filtration.

Describe diffusion.

The movement of atoms, molecules, or ions from a region of higher concentration to a region of lower concentration.

Define osmotic pressure.

The ability of osmosis to generate enough pressure to lift a volume of water.

What is tonicity?

The ability of a solution outside a cell to alter the water volume inside of a cell.

What happens to a cell in an isotonic solution?

There is no net gain or loss of water; cells maintain normal cell volume.

Define active processes in molecule movements.

Active processes require ATP to move substances across the cell membrane, such as active transport, endocytosis, and exocytosis.

Describe active transport.

Movement of substances across a membrane from a region of lower concentration to a region of higher concentration (against concentration gradient).

Define interphase and mitosis.

Interphase is the growth phase of the cell; Mitosis is the division of the nucleus.

What occurs during the S phase of the cell cycle?

DNA is replicated during this phase.

Describe prophase in mitosis.

Chromatin condenses into chromosomes; centrioles move to opposite sides of the cytoplasm, and the nuclear envelope disperses.

Define apoptosis and necrosis.

Apoptosis is a form of programmed cell death; necrosis is cell death resulting from damage.

Define metabolism.

The sum of all chemical reactions in the body.

What is anabolism?

The process of building small molecules into larger ones, which requires energy.

What are enzymes made of?

Long chains of amino acids.

What is the function of enzymes?

To control the rate of catabolic and anabolic reactions and to greatly increase the reaction rate.

What does ATP stand for and what is its function?

ATP = Adenosine Triphosphate; its function is to power cellular activities.

What does DNA stand for?

DNA = Deoxyribonucleic Acid.

What is the main function of DNA?

To store the biological code needed to build and reproduce organisms and guide protein production.

Describe DNA replication.

The process where a cell makes an exact copy of its DNA before dividing.

What does RNA stand for?

RNA = Ribonucleic Acid.

What is the sugar in RNA?

The sugar in RNA is ribose.

What are the 4 nitrogenous bases in RNA?

1. Adenine (A), 2. Guanine (G), 3. Cytosine (C), 4. Uracil (U).

Define tissue.

A group of similar cells with a common function.

What are the 4 major types of tissues?

1. Epithelial tissue, 2. Connective tissue, 3. Muscle tissue, 4. Nervous tissue.

What are tight junctions?

Close spaces between cells by fusing cell membranes.

Name the functions of epithelial tissues.

Protection, secretion, absorption, and excretion.

Where is the free surface of an epithelial tissue located?

Covers body surfaces, internal organs, and composes glands.

Do epithelial tissues have blood vessels?

No, they lack blood vessels, so nutrients must diffuse from underlying connective tissue.

What is the difference between endocrine and exocrine glands?

Endocrine glands secrete into tissue fluid or blood, while exocrine glands secrete into ducts.

Define merocrine, apocrine, and holocrine glands.

Merocrine glands secrete fluid products by exocytosis; apocrine glands lose small parts of the cell during secretion; holocrine glands release entire cells filled with products.

What is the function of fibroblasts?

They secrete fibers into the extracellular matrix.

What are the three types of fibers in connective tissue?

1. Collagen fibers, 2. Elastic (yellow) fibers, 3. Reticular fibers.

What is the name for a cartilage cell?

Chondrocyte.

Name three types of cartilage.

1. Hyaline cartilage, 2. Elastic cartilage, 3. Fibrocartilage.

List the characteristics and functions of bone.

Supports, protects, and provides a framework; comprises cells in a solid matrix.

What are the primary functions of red blood cells, white blood cells, and platelets?

Red blood cells transport gases; white blood cells defend against infection; platelets help in blood clotting.