ANAPHY: LESSON 3 - CELL STRUCTURE & THEIR FUNCTIONS

ngadi nastart na adto pagkuri

Cell

are composed of chemicals, and those chemicals are responsible for its characteristics

Cells

determine the form and functions of the human body.

Cell

The basic living unit of all organisms.

Cell

They are complex living structures. They have many characteristics in common; however, most of them are also specialized to perform specific functions.

Cell

a highly organized unit.

Organelles

Specialized structures within a cell that perform specific functions.

Nucleus

An organelle containing the cell's genetic material.

Cytoplasm

The living material surrounding the nucleus.

Cell Membrane

It encloses the cytoplasm.

Cells

are “the smallest units of life”, meaning they have all the characteristics of life.

1. Cell metabolism and energy use

2. Synthesis of molecules

3. Communication

4. Reproduction and inheritance

Four important functions performed by cells

Cell Metabolism

The chemical reactions that occur within a cell to maintain life.

Synthesis of Molecules

The process of creating new molecules within a cell.

Communication

The exchange of information between cells.

Cell membrane

It is the outermost component of a cell.

Cell membrane

It encloses the cytoplasm and forms the boundary between the material inside the cell and the material outside it.

Reproduction and Inheritance

The processes by which cells reproduce and pass on genetic information.

extracellular substances

Substances outside the cell

intracellular substances

Substances inside the cell

1. supporting the cell contents

2. acting as a selective barrier that determines what moves into and out of the cell

3. playing a role in communication between cells.

other functions of cell membrane

1. phospholipids

2. proteins

two major molecules that make up the cell membrane

3. cholesterol

4. carbohydrates.

the cell membrane contains two other molecules

Receptor molecules

are part of an intercellular communication system that enables cell recognition and coordination of the activities of cells.

selectively permeable

Cell membranes are like this since they allow some substances, but not others, to pass into or out of the cells.

1. Passive membrane transport

2. Active membrane transport

two types of movement through the cell membrane

Passive membrane transport

Movement through the cell membrane that does not require the cell to expend energy.

Active membrane transport

Movement through the cell membrane does require the cell to expend energy, usually in the form of ATP.

1. diffusion

2. osmosis

3. facilitated diffusion.

Passive membrane transport mechanisms

1. active transport

2. secondary active transport

3. endocytosis

4. exocytosis

Active membrane transport mechanisms

Diffusion

The process when solutes move from an area of higher concentration to an area of lower concentration in a solution.

solution

is generally composed of one or more substances, called solutes and solvents

concentration gradient

the difference in the concentration of a solute in a solvent between two points divided by the distance between the two points.

Osmosis

The diffusion of water across a selectively permeable membrane from a region of higher concentration to one of lower concentration.

Osmotic pressure

the force required to prevent the movement of water across a selectively permeable membrane.

Hypotonic solution

A solution with a lower concentration of solutes and a higher concentration of water relative to the cytoplasm of a cell.

Hypotonic solution

if a cell is immersed in this solution, water moves by osmosis into the cell where the solute concentration is greater, causing the cell to swell.

lysis

If the cell swells enough, it can rupture

Isotonic solution

the concentrations of various solutes and water are the same on both sides of the cell membrane. The cell therefore neither shrinks nor swells

Hypertonic solution

the solution usually has a higher concentration of solutes and a lower concentration of water relative to the cytoplasm of the cell.

Hypertonic solution

Water moves by osmosis from the cell into this solution, resulting in cell shrinkage, or crenation

Facilitated Diffusion

The process in which a carrier molecule binds with a molecule on the outside of the cell membrane and changes shape to release the molecule on the inside of the cell membrane.

Facilitated diffusion

is a carrier-mediated transport process that moves substances across the cell membrane from an area of higher concentration to an area of lower concentration of that substance

1. size

2. shape

3. charge

characteristics of an ion or molecule that can determine if it can pass through a channel

1. leak channels

2. gated channels

two classes of cell membrane channels

leak channels

channels constantly allow ions to pass through.

gated channels

Other channels limit the movement of ions across the membrane by opening and closing

Carrier molecules

which are proteins within the cell membrane,are involved in carrier-mediated transport mechanisms, which move large, water-soluble molecules or electrically charged ions across the cell membrane.

Carrier-Mediated Transport Mechanisms

Mechanisms in which carrier molecules, proteins within the cell membrane, are involved in transporting specific nutrient molecules.

specificity

only specific molecules are transported by the carriers

Active Transport

a carrier-mediated process that moves substances across the cell membrane from regions of lower concentration to those of higher concentration against a concentration gradient. It requires energy in the form of ATP.

Cystic fibrosis

is a genetic disorder that affects the active transport of Cl− into cells

Secondary active transport

involves the active transport of one substance, such as Na+, across the cell membrane, establishing a concentration gradient which then provides the energy to transport a second substance across the cell membrane.

Cotransport

the diffusing substance moves in the same direction as the transported substance

counter transport

the diffusing substance moves in a direction opposite to that of the transported substance.

Endocytosis

is the uptake of material through the cell membrane by the formation of a vesicle

receptor-mediated endocytosis

A process when a specific substance binds to the receptor molecule, endocytosis is triggered, and the substance is transported into the cell.

phagocytosis

is often used for endocytosis when solid particles are ingested. It is when white blood cells take up and destroy harmful substances that have entered the body.

Pinocytosis

is distinguished from phagocytosis in that much smaller vesicles are formed, and they contain liquid rather than particles.

Exocytosis

release of substances from the cell through fusion of a vesicle with the cell membrane.

Nucleus

A large organelle usually located near the center of the cell that contains the cell's genetic material.

Nuclear Envelope

separates the contents of the nucleus from the rest of the cytoplasm. Consists of outer and inner membranes with a narrow space between them.

Nuclear pores

Openings in the nuclear envelope that allow for the transport of molecules between the nucleus and the cytoplasm.

Chromosomes

Organized into 23 pairs. They are structures made of DNA and proteins that carry genetic information.

chromatin

chromosomes that loosely coiled and collectively

Nucleoli

are diffuse bodies with no surrounding membrane that are found within the nucleus

Ribosome

An organelle in the cytoplasm that is the site of protein synthesis.

free ribosomes

Ribosomes that are not attached to any other organelle.

endoplasmic reticulum

is a series of membranes forming sacs and tubules that extends from the outer nuclear membrane into the cytoplasm

Rough endoplasmic reticulum

is ER with ribosomes attached to it.

Smooth endoplasmic reticulum

ER without ribosomes. It is a site for lipid synthesis and participates in detoxification of chemicals within cells. In skeletal muscle cells, it stores calcium ions.

Golgi Apparatus

consists of closely packed stacks of curved, membrane-bound sacs. Organelle that collects, modifies, packages, and distributes proteins and lipids manufactured by the endoplasmic reticulum.

Secretory vesicles

Small, membrane-bound sacs that transport or store materials within cells and are formed from the Golgi apparatus.

Lysosome

Are membrane-bound vesicles formed from the Golgi apparatus. An organelle in the cytoplasm that contains enzymes that digest material taken into the cell.

Lysosomes

Membrane-bound vesicles that contain enzymes for intracellular digestion.

Peroxisomes

Small membrane-bound vesicles that contain enzymes for breaking down fatty acids, amino acids, and hydrogen peroxide.

Mitochondrion

An organelle in the cytoplasm that is the site of aerobic respiration and the major site of ATP synthesis.

Mitochondria

Small organelles with inner and outer membranes that are the major site of ATP production within cells.

cristae

Inner membranes of the mitochondria that have numerous folds, which project like shelves into the interior of the mitochondria.

Mitochondrial Matrix

the material within the inner membrane of the mitochondria.

Mitochondrial DNA

enzymes in the mitochondria

Cytoskeleton

Internal framework of the cell. It consists of proteins that support the cell, hold organelles in place, and enable the cell to change shape.

1. microtubules

2. microfilaments

3. intermediate filaments

protein structures of a cytoskeleton

Microtubule

are hollow structures formed from protein subunits. They perform a variety of roles, such as helping support the cytoplasm of cells, assisting in cell division, and forming essential components of certain organelles, such as cilia and flagella.

Microfilaments

small fibrils formed from protein subunits that structurally support the cytoplasm. Some microfilaments are involved with cell movement.

Intermediate filaments

are fibrils formed from protein subunits that are smaller in diameter than microtubules but larger in diameter than microfilaments. They provide mechanical support to the cell.

Centrosome

A specialized zone of cytoplasm close to the nucleus where microtubule formation occurs. It contains two centrioles that are normally oriented perpendicular to each other.

centriole

is a small, cylindrical organelle composed of nine triplets; each triplet consists of three parallel microtubules joined together

Cilia

Cylindrical structures that project from the surface of cells and are capable of moving. It is composed of microtubules

Flagella

have a structure similar to that of cilia but are much longer, and they usually occur only one per cell.

Microvilli

are specialized extensions of the cell membrane that are supported by microfilaments, but they do not actively move as cilia and flagella do.

Microvilli

Extensions on the cell surface that increase the surface area of certain cells.

Gene expression

The process by which DNA provides instructions for making a specific protein.

gene

is a sequence of nucleotides that provides a chemical set of instructions for making a specific protein.

Transcription

The process of making a complementary copy of a gene in the form of messenger RNA (mRNA).

Translation

The process of converting the information in mRNA into a protein.

Codons

Groups of three nucleotides in mRNA that carry the information for a specific amino acid.

Interphase

The nondividing phase of the cell cycle, during which DNA is replicated.

Mitosis

The process of cell division that forms two daughter cells with the same amount and type of DNA as the parent cell.

Meiosis

The process of cell division that forms sex cells with half the number of chromosomes as other cells.

Diploid

The number of chromosomes in most cells of the human body, which is 46 organized into 23 pairs.