Anatomy Chapter 3 Part 1 (Cells) Study Guide

When will molecules qualify for diffusion?

1) If they are small enough to pass through the plasma membrane's pores or 2) they can dissolve in the fatty portion of the membrane.

Cytokenisis

Begins in late anaphase and ends during telophase, this is the phase where all the cytoplasm is duplicated and the cleavage furrow begins to form.

Pinocytosis

Bulk transport process in which the membrane invaginates to from a tiny pit and then its edges fuse around the droplet of extracellular fluid containing dissolved proteins or fats. - Also means that the cell "drinks" - Fluid-phase endocytosis

Phagocytosis

Bulk transport process where the membrane engulfs rather larger particles such as bacteria or dead body cells separated from the external environment by flowing cytoplasmic extensions called pseudopods. Act as the police; protective mechanism. - Also means that the cell is "eating"

Cytoplasm

Cellular material outside the nucleus and inside the plasma membrane.

Cytoplasmic Organelles

Cellular materials outside the nucleus and inside the plasma membrane. The site of most cellular activities; "factory" of the cell. Cellular life depends upon these functions.

Cillia

Cellular projection that moves things across the cell membrane.

Flagella

Cellular projection that propels the cell.

What are nuclear pores?

Complexes made of proteins also known as nucleoporins. Allow for the transportation of molecules across the nuclear envelope.

What is the Nucleus (structure and function)?

Control center of the cell, contains DNA, and contains instructions for building proteins. The DNA is necessary for cell reproduction. Nucleus conforms to the shape of its cell.

3 major elements of cytoplasm

Cytosol, organelles, and inclusions.

Examples of passive transport:

Diffusion, simple diffusion, osmosis, facilitated diffusion, and filtration.

Microfilaments

Double helix shaped; most involved in cell motility and in producing changes in cell shape.

What are the cells that cover and line body organs?

Epithelial Cells: A hexagonal shaped cell that is built to stretch; built with abundant intermediate filaments that resist tearing when epithelium is rubbed or pulled. The cells can easily pack together together in sheets to line the body organs.

Inclusions

Everything except organelles; chemical substances that may or may not be present, storing nutrients or cell products.

Bulk Transport

Exocytosis and endocytosis

What are the cells that store nutrients?

Fat Cells: Huge spherical shape of a fat cell is produced by a large lipid droplet in cytoplasm.

What are the cells that connect body parts?

Fibroblast Cells: Most common cell in connective tissue; the elongated shape of this cell lies along the cable-like fibers it secretes. Has an abundance in rough ER and a large Golgi apparatus to make and secrete the building blocks of these fibers. Erythrocyte Cells: Red Blood Cells; carries oxygen in and throughout the bloodstream to all regions of the body.

What are the purpose of Gap Junctions? Give an example of where they are found.

Purpose to allow communications. Neighboring cells connected by connexons, hollow. EX: found on coverings of nerves and smooth muscles.

Lysosomes

Structure: Membranous "bags" containing powerful digestive enzymes. Function: Demolition site of the cell; engulfs and destroys all that a cell does not want/need. Also though of as a cleanup crew/detect and protect (ex: white blood cells).

Peroxisomes

Structure: Membranous sac containing powerful oxidase. Function: Enzymes that use molecular oxygen to detoxify a number of harmful substances. It disarms free radicals and converts them to H2O2. (type of lysosome)

Centrisomes

Structure: Rod-shaped bodies lying at right angles of each other; bundles of proteins with a centriole at the center. Lay near the nucleus. Function: Directs the formation of the mitotic spindle during cellular division.

Golgi apparatus

Structure: Swarms of tiny vesicles usually found close to the Nucleus, looking very similar to the Smooth ER. Function: Packaging and delivery center of the cell, packing and delivering proteins according to their final destinations.

Cytoskeleton

Structure: Thin threadlike strands of proteins made up of either intermediate filaments, micro filaments, or microtubules. Function: Maintain the structure and shape of the cell; the cell's "bones", supports other organelles, and provides the machinery needed for intracellular transport & various types of cellular movement.

Ribosomes

Structure: Tiny dark bodies made of proteins and one variety of RNA. Function: Sites of protein synthesis (protein production). Fixed: involved in exportation and attach to ER Free: used inside the cell for production

Mitochondria

Structure: Tiny threadlike bean shaped structure; in living cells they squirm, lengthen, and change in shape. Contains its own DNA. Function: Provides energy (ATP) for cellular activities. Female passes down Mitochondrial DNA to offspring in reproduction.

What is a solvent?

Substance present in the greater amount of the solution; substance that is dissolving.

What is a solute?

Substance that is present in the lesser amounts of the solution; what is being dissolved.

Two types of proteins involved in the plasma membrane?

Superficial and Integral.

What do most all cells share in common?

The ability to metabolize, digest food, dispose of waste, reproduce, grow, move, and respond to stimulus.

Selective permeability

The allowance of some substance to pass through while excluding others.

What is simple diffusion?

The unassisted diffusion of solutes through the plasma membrane. These solutes are either small enough to pass through the pores of the membrane, or lipid-soluble.

What are the three membrane junctions?

Tight, Desmosomes, and Gap junctions.

Solute Pumping

Transports amino acids, some sugars, and Na+ through the plasma membrane using ATP (energy) and most commonly working against the concentration gradient (areas of low concentration to high).

How are proteins synthesized?

1) mRNA specifying one polypeptide is made on DNA template. 2) mRNA leaves the nucleus and attaches to ribosome, translation begins. 3) Incoming tRNA recognizes a complementary mRNA codon calling for its amino acid by binding via anticodon to the codon. 4) As the ribosome moves along the mRNA, a new amino acid is added to the growing protein chain. 5) Released tRNA re-enters the cytoplasmic pool, ready to be recharged with a new amino acid.

What is the structure and function of the Nuclear envelope?

A double membrane barrier that binds the nucleus. At various points two layers fuse, and nuclear pores penetrate through fused regions. Selectively permeable, but much freer because of large pores. Encloses the nucleoplasm.

What is a solution?

A homogeneous mixture of two or more components.

What is Chromatin?

A loose network of bumpy threads formed when DNA is combined with protein and a cell is not dividing.

What is the Plasma Membrane?

A semipermeable barrier that contains the cell contents and separates them from their surrounding environment. Manly made of two layers of lipids called phospholipids, but also contains cholesterol.

What is a Nucleolous?

A small and dark-stained essentially round body where ribosomes assemble in the Nucleus. Serves as site of protein synthesis.

Intracellular fluid

A solution containing small amounts of gases, nutrients, and salts, dissolved in water.

What are the purpose of Desmosomes Junctions? Give an example of were they are found.

Anchoring junctions preventing cells subject to mechanical stress from being pulled apart. These junctions are like button like thickenings of adjacent plasma membranes, connected by fire protein filaments. Forms an internal system of strong guy wires. EX: Skin cells.

Intersticial fluid

Fluid that bathes the exterior of our cells, containing but not limited to: nutrients, regulatory substances such as hormones and neurotransmitters, salts, and waste products.

"Function follows ____."

Form

Microvilli

Forms the lining in hollow body organs (ex: small intestines) . Tiny finger-like projections that greatly increase the cells surface area for absorption so that the process occurs more quickly.

rRNA

Forms the ribosomes where proteins are being built.

Microtubules

Hollow spiral tubes; determine the overall shape of a cell and distribution of organelles.

What are the purpose of Tight Junctions? Give an example of where they are found.

Impermeable junctions that bind cells together into leak proof sheets that prevent substances from passing through extracellular space between cells. Adjacent membranes fuse tightly like a zipper. EX: In the small intestines they prevent digestive enzymes from seeping to the blood stream.

What are membrane junctions?

Important in enabling communication between neighbor cells via specialized protiens.

What is the nucleoplasm?

Jelly like fluid enclosed by the nuclear envelope in which other nuclear elements are suspended.

What are the responsibilities of Superficial proteins?

Known as peripheral, these are binding sites that stick off of the inside or outside of a cell.

mRNA

Long single nucleotide strands that resemble half of a DNA molecule and carry the "message" containing instructions for protein synthesis from the DNA gene in the nucleus to the ribosomes in the cytoplasm.

Interphase

Longest phase of the cell; divided into three phases, G1, S, G2. In this phase the cell grows and matures. - During S stage the DNA duplicates

What are the cells that fight disease?

Macrophage Cells: Extends long pseudopods (fake feet) to crawl through tissue to reach infection sites. The many lysosomes within the cell digest the infections the microorganisms it takes up.

Passive transport

Membrane transport that does not require energy.

Active transport

Membrane transport that requires energy (ATP).

Organelles

Metabolic "machinery" of the cell, specialized to carry out specific functions for the cell as a whole. Some synthesize proteins other package proteins.

Cellular projections (extensions of the PM)

Microvilli, Cilia, and Flagella.

Diffusion

Movement of molecules from a region of higher concentration to a region of lower concentration. They move down the concentration gradient. Speed affected by size of molecule.

Exocytosis

Moves substances outside of the cell; actively secretes hormones, mucus, and other cell products or ejects waste.

What are the cells that gather information and control body functions?

Nerve Cells: This cell has long processes for receiving messages and transmitting them to other structures in the body. The processes are covered with an extensive plasma membrane and an abundance of rough ER is present to synthesize membrane components.

What are the three recognizable regions/structures of the Nucleus?

Nuclear envelope/nuclear membrane, nucleoli, and chromatin.

What are the three main regions of all cells?

Nucleus, Cytoplasm, and Plasma Membrane.

Transcription

The transfer of information from DNA's base sequence into the complementary base sequence of mRNA.

What are the cells used for reproduction?

Oocyte Cells: Strictly found in females, the largest cell in the body contains many copies of all organelles, for distribution to the daughter cells that arise when the fertilized egg divides to become an embryo. Sperm Cells: Strictly found in males, this cell is long and string like built for swimming to the oocyte for fertilization. Its flagellum acts as a motile whip to propel the sperm.

What is osmosis?

Osmosis is the diffusion of water through a semipermeable membrane.

What are phagocytic cells?

Phagocytic cells are the cells that help protect the body by ingesting harmful foreign particles, bacteria,and dead or dying cells.

RNA

Practically a slave to DNA, it acts as a decoder and carries messages to achieve its task of specifying the structure of proteins to be built t the ribosomes. - Has three varieties that carry out separate cellular processes

Filtration

Process by which water and solutes are forced through a membrane by fluid or hydrostatic pressure. Pressure gradient pushes solute containing fluid from higher to lower concentration. Driven by kinetic energy of dissolving molecules.

Endocytosis

Processes that take up or engulf extracellular substances by enclosing them in small membranous vesicles. - Phagocytosis & Pinocytosis

What is facilitated diffusion?

Provides passage for certain needed substances (notably glucose) that are both lipid-insoluble and too large to pass through the membrane pores. Although it travels down its own concentration gradient, a protein channel is used or a protein molecule that acts as a carrier.

Metaphase

Second stage of mitosis; shortest phase, chromosomes line up on the cellular equator and attach to spindle fibers.

Cytosol

Semitransparent fluid that suspends the other elements. Consists mostly of water but also contains nutrients and a variety of other solutes.

What are the cells that move organs and body parts?

Skeletal Muscle and Smooth Muscle Cells: Elongated cells filled with abundant contractile filaments. This allows them to shorten forcefully, move the bones, and/or change the size of internal organs.

tRNA

Small clover shaped molecules that transfer

Examples of active transport:

Solute pumping and bulk transport.

What are the responsibilities of integral proteins?

Span the entire membrane and provide transportation.

Intermediate filaments

Strong, stable, rope-like; help form desmosomes and provide internal wires to resist pulling forces on the cell.

ER: rough

Structure: "Network" of the cell; system of fluid-filled cisterns that coil and twist through the cytoplasm, studded with ribosomes. Function: Involved in protein synthesis and transportation.

ER: smooth

Structure: "Network" of the cell; system of fluid-filled cisterns that coil and twist through the cytoplasm. Often confused with Golgi apparatus, remember that the Golgi apparatus will be closer to the Nucleus. Function: Makes cholesterol and detoxifies (found in the kidneys and liver).

How does cholesterol benefit the Plasma Membrane?

The cholesterol embedded in lipid interior makes the membrane firm (prevents it from becoming rigid) and prevents the membrane from freezing in low temperatures. Supports and regulates the fluidity.

Cytokinesis

The division of the cytoplasm.

Mitosis

The division of the nucleus and all its genetic material.

Prophase

The first stage of mitosis; nuclear envelope and membrane disappear, chromosomes are visible for the first time, and spindle fibers connecting to the centrioles form.

Telophase

The fourth and final stage of mitosis; nuclear envelop and membrane reappear and chromosomes unwind to chromatin.

DNA

The genetic material in a cell. Very complex composed of nucleotides, each of which are built from deoxyribose sugar, a phosphate group, and a nitrogen containing base. - Double helix or twisted "ladder" in which the nitrogen containing bases are the rungs and the vertical poles are alternating phosphate and sugar units.

Translation

The language of nucleic acids is translated into the language of proteins. - Base sequence to Acid Sequence

Receptor-mediated endocytosis

The main cellular mechanism for taking up specific target molecules.

Hydrophobic

The nonpolar "tails" fatty acids of the phospholipids avoid water, lining up in the center of the membrane because they're...

Hydrophilic

The polar (water loving) "heads" phospholipids are...

Anaphase

The third stage of mitosis; centromeres of chromosomes are pulled apart by spindle fibers and chromatids are pulled to opposite poles. Ends when they reach poles/stop moving. Cell elongates.