Anatomy: Cells (Ch. 3)

The smallest living unit of the human body is the

Cell

Which of the following best describe the plasma membrane

A phosophlipid bilayer surrounding the cell

Which statement correctly describes the structure of the plasma membrane?

Protein and cholesterol are embedded within the phospholipid bilayer, forming a fluid mosaic

The organelles and the water component of the cell together are called the

Cytoplasm

The water component of the cytoplasm is called the

Cytosol

Most eukaryotic cells contain a membrane-bound _______ that houses the genetic material

Nucleus

Some cells contain many mitochondria, while other contain few or none. This suggest that

Cells with many mitochondria have high energy demands

Which organelle consists of a network of intracellular membranes with attached ribosomes?

Rough endoplasmic reticulum

Lipid and glycogen synthesis primarily occurs in the

Smooth endoplasmic reticulum

When activated, lysosomes primarily function in

Digestion of foreign material and worn-out organelles

What is a cell?

the structural and functional unit of life

What is a plasma membrane?

Flexible outer boundary containing a phospholipid bilayer; Acts as an active barrier separating intracellular fluid (ICF) from extracellular fluid (ECF); plays a dynamic role in cellular activity by controlling what enters and what leaves cell

What is a cytoplasm?

Intracellular fluid containing organelles

What is a nucleus?

DNA containing control center

What makes up the structure of plasma membrane?

Consists of membrane lipids that form a flexible lipid bilayer; specialized membrane proteins; surface sugars form glycocalyx; cholesterol

What is hydrophilic and hydrophobic?

Hydrophilic is water-loving (phosphate head with that are polar, charged), Hydrophobic is water-hating (fatty acid tails, nonpolar - no charge)

What are the two types of membrane proteins?

Integral proteins (bound into the membrane; ex. channels, carriers, receptors, enzyme), Peripheral proteins (loosely attached to integral proteins; ex. enzymes, cell-to-cell connections)

What is glycocalyx?

Consists of sugars (carbohydrates) sticking out of cell surface (attached to lipids - glycolipids, attached to protein - glycoproteins); Functions as specific biological markers for cell-to-cell recognition; Allows immune system to recognize “self” vs. “nonself”

Clinical - Homeostatic Imbalance related to glycocalyx and cancer

Glycocalyx of some cancer cell can change so rapidly that the immune system can’t recognize the cell as being damaged; Mutated cell is not destroyed by immune system so it is able to replicate

What are the cell junctions?

Tight Junctions, Desmosomes, Gap junction

What is a tight junction?

Integral proteins on adjacent cells fuse to form an impermeable junction that encircles whole cell; prevents fluids and most molecules from moving in between cells

What is a desmosomes?

Rivet-like cell junction formed when linker proteins (cadherins) of neighboring cells interlock like the teeth of a zipper; Desmosomes allow “give” between cells, reducing the possibility of tearing under tension

What is gap junctions?

Transmembrane proteins (connexons) form tunnels that allow small molecules (ions, simple sugars) to pass from cell to cell; Allows electrical signals to be passed quickly from one cell to the next cell (ex. cardiac and smooth muscle cells)

What is cytoplasm and what is it composed of?

Cytoplasm holds all cellular material that is located between the plasma membrane and the nucleus; Cytoplasm contains cytosol, inclusions (insoluble molecules, ex. glycogen granules, lipid droplets), and organelles (metabolic machinery structures of cell).

What are all cytoplasmic organelles, membranous and nonmembranous?

Membranous: Mitochondira, Endoplasmic reticulum, Golgi apparatus, Peroxisomes, Lysosomes
Nonmembranous: Ribosomes, Cytoskeleton, Centrioles

What is the function of the mitochondrion and what is cristae?

Mitochondrion is considered “power plant” of cells because it produces most of the cell’s energy molecules (ATP) via aerobic cellular respiration.
Mitochondria have double membrane and the folds in the inner membrane is called cristae

What is the function of ribosomes, what is it made of, and what are the two forms?

Ribosomes are nonmembranous organelles that are site of protein synthesis.
Ribosomes is made up of protein and ribosomal RNA (rRNA).
The two forms of ribosomes are: Free ribosomes (free floating), Membrane-bound ribosomes (attached to membrane of endoplasmic reticulum)

What are the two types of endoplasmic reticulum (ER)

Rough ER and Smooth ER

What is the function rough ER?

Site of synthesis of proteins that will be secreted from cell
Site of synthesis of mana plasma membrane proteins

What is the function of smooth ER?

Lipid metabolism; lipids, cholesterol, and steroid-based hormone synthesis;
Synthesis of glycogen; Absorption, synthesis, and transport of fats

What is the function of Golgi Apparatus?

Modifies, concentrates, and packages proteins and lipids received from rough ER. Made up of stacked and flattened membranous cistern sacs

What are the steps of protein synthesis on the rough ER to the final distribution of those proteins

Production of protein by the RER.
1. Protein-containing vesicles pinch off rough ER and migrate to fuse with membranes of golgi apparatus.
2. Proteins are modified within the Golgi compartments.
3. Proteins are then packaged within different vesicles types, depending on their ultimate destination.

What is the function of peroxisomes?

Membranous sacs containing powerful detoxifying substances that neutralize toxins

What is the function of lysosomes and what does it contain to do that function?

The function of lysosomes is to digest ingested bacteria, viruses, and toxins; Degrade nonfunctional organelles; remove cellular debris.
Contains spherical membranous bags containing digestive enzymes (acid hydrolases)

What is autolysis?

The destruction of all or part of a cell, tissue, or organisms by its own self-produced internal enzymes

What are the three protein fibers found in cytoskeleton?

Microfilaments, Intermediate filaments, and Microtubules

What is the function of cytoskeleton?

Acts as the cell’s “bones, ligaments, and muscles” by playing a role in movement of cell componenets

What is cilia, flagella and microvilli?

Cilia and flagella aid in the movement of the cell or of material across the surface of the cell.
Microvilli are fingerlike projections that extend from the surface of the cell to increase surface area to improve the absorption of nutrients

What does nucleus contain and what is the function?

Largest organelle; contains the genetic library of blueprint for syntehsis of nearly all cellular proteins (DNA); Responds to signals taht dictate the kinds and amounts of proteis that need to be synthesized

What is uninucleate, multinucleate, and anucleate?

Uninucleate has one nucleus (ex. most cells), Multinucleate have many nuclei (ex. skeletal muscles, bone cells and some liver cells), Anucleate has no nucleus (RBC)

What are the three main structure of the nucleus?

Nuclear envelope, Nucleoli, Chromatin

Where is nucleoli found and what is its function?

Nucleoli is dark-stsaining spherical bodies within the nucleus that are involved in ribosomal RNA (rRNA) synthesis and ribosome subunit assembly

What is chromatin and what is it made up of?

Chromatin is a complex mixture of DNA, RNA, and proteins that packages long DNA molecules into dense, compact structures inside the nucleus of a eukaryotic cell.
30% threadlike strans of DNA, 60% histone proteins, and 10% RNA

What is nucleosomes?

The basic repeating structural unit of chromatin, which consists of a segment of DNA wrapped around a core of histone proteins

What is chromosomes?

Chromosomes are condensed chromatin; Condensed state help protect fragile chromatin threads during cell division

What is autophagy?

Autophagy (self-eating) is the process of disposing of nonfunctional organelles and cytoplasmic bits by forming autophagosomes, which can then be degraded by lysosomes

What is Apoptosis? what is the process?

Also known as programmed cell death, causes certain cells (ex. cancer cells, infected cells, old cells) to neatly self-destruct
1. Process begins with mitochondrial membranes leaking chemicals that activate enzyme called caspases.
2. Caspases cause degradation of DNA and cytoskeleton, which leads to cell death
3. Dead cell shrinks and is phagocytized by macrophages

What are the two types of cell death?

1. Apoptosis (Cell breaks apart into several apoptotic bodies, which are then phagocytosed. no inflammation.)

   1. Necrosis (Plasma membrane rupture. Cellular and nuclear lysis causes inflammation)