[0] CELLULAR ORGANIZATION

Cells

basic unit of life or living organism.

Cells are highly organized and ____

has a constant energy source to maintain order in the system.

Basic properties of a cell

-highly complex and structurally organized to contain genetic information
-capable of reproduction and self-regulation.
-acquires and utilizes energy to maintain homeostasis.
-engages in mechanical and metabolic activities in the body.
-senses and responds to changes in the surrounding environment

3 Basic Cellular Requirements

-materials
-information system
-energy

materials

-carbohydrates
-lipids
-proteins

information system

-enzymes
-hormones and neurotransmitters

energy

-atp

carbohydrates is found in ____

plant cell wall (cellulose) and bacterial cell wall (peptidoglycan)

carbohydrates is found in plant cell wall (____) and bacterial cell wall (peptidoglycan)

cellulose

carbohydrates is found in plant cell wall (cellulose) and bacterial cell wall (_____)

peptidoglycan

which materials serve as source of energy?

carbohydrates and lipids

lipids is part of?

cell membrane composition

Proteins has vital role for

structural integrity and function of cells.

proteins aid in?

catalytic reactions (enzymes).

Enzymes

It speeds up chemical reactions.

enzymes Uses ____ to direct synthesis of necessary enzymes.

enzyme markers

Hormones and Neurotransmitters

Depends on necessary enzymes for their synthesis.

Hormones and Neurotransmitters can serve as?

"signal" molecules to facilitate communication as a cellular level

ATP (Adenosine triphosphate)

serves as the energy currency of the cell

Nucleus
prokaryotic cells

No definite nucleus; DNA is scattered within the cell membrane

Cell Membrane (Plasma Membrane)
prokaryotic cells

Present with cell wall

Mitochondria
prokaryotic cells

None; Enzymes for REDOX reactions are scattered in the cell membrane

Endoplasmic Reticulum
prokaryotic cells

none

Ribosomes
prokaryotic cells

present

Chloroplast
prokaryotic cells

None; Photosynthesis (if capable) is localized in chromatophores

Cell Membrane
Characteristics

A thin film of lipids (glycolipids, arachidonic acid, phospholipids) and proteins (glycoproteins) held together by non-covalent interactions

Cell Membrane
Function

-serves as semi-permeable membrane to protect the cellular content.
-compartmentalizes cellular content and acts as scaffold for biochemical processes.
-facilitates cellular communication via external signals.

Mitochondria
function

-serves as the powerhouse of the cell.
-Generates ATP via carbohydrate and lipid breakdown

Mitochondria
characteristics

It contains its own DNA, tRNA, rRNA, ribosomes, and enzymes. It has porins (outer membrane) and cristae (inner membrane) that functions in energy production

Ribosomes
Characteristics

It is made up of 2 components: small and large ribosomal units. The units are measured in Svedberg units (S).

Ribosomes
Function

-It serves as the site for protein synthesis by linking amino acids based on a mRNA template.
-Components: Eukaryote - 80S (40S, 60S), Prokaryotes - 70S (30S, 50S)

Endoplasmic Reticulum
characteristics

largest cell organelle directly connected to the nucleus. It is made up of single-membrane tubules and sacs (cisternae)

cisternae

single-membrane tubules and sacs of er

Endoplasmic Reticulum
function

It manufactures and packages mature proteins and lipids for storage in vesicles

Rough endoplasmic reticulum (RER)

is made up of flattened sheets in the outer nuclear membrane. It has ribosomes at the cytosolic side of the membrane,

Smooth endoplasmic reticulum (SER)

is tubular in shape situated near the RER.

Rough Endoplasmic Reticulum (RER)
function

-Site for protein synthesis via the ribosomes in the RER.
-The ER cisternae holds the proteins for structural maturation.

Smooth Endoplasmic Reticulum (SER)
function

-It is involved in lipid metabolism.
-It is also aids in protein metabolism, synthesis of neutral fat, phospholipids, and steroids.
-It also has roles in drug detoxification process.

Golgi Apparatus
Characteristics

It is a "double-faced" organelle (cis/trans face

Cis face golgi apparatus

receives unmodified/immature proteins or lipids from ER.

trans face Golgi Apparatus

releases mature/modified biomolecules packed in vesicles

Golgi Apparatus
function

-It aids in the packaging and storage of cellular substances.
-It gathers simple biomolecules and packs them in vesicles creating more complex molecules.

Lysosomes
characteristics

spherical vesicle with hydrolytic enzymes responsible for the breakdown of obsolete /unused biomolecules in the cytoplasm.

Lysosomes
function

-It serves as the "suicide bag" of the cell.
-It can releases hydrolytic enzymes and free radicals to target specific molecules and trigger APOPTOSIS (programmed cell death)

Nucleus
Characteristics

the distinguishing feature between eukaryotes and prokaryotes. It is composed of chromosomes (tightly coiled DNA), nucleolus (site of ribosomal assembly), nuclear membrane.

Nucleus
function

-It serves as the control center of the cell.
-It maintains cellular integrity and control cellular activities by regulating gene expression.

Chloroplast
Characteristics

-It is found among photosynthetic organisms.
-It synthesizes its own amino acids, fatty acids, and lipid components for their membranes

Chloroplast
Function

-It harness solar energy for photosynthesis producing ATP.
-It also uses solar energy to convert CO2 and H2O into carbohydrates

Vacuole
Characteristics

-It is present in plants cells and occupies about 90% of its cell volume.
-It contains enzymes for intracellular digestion.

Vacuole
Function

-It stores nutrients, wastes, and specialized materials like pigments.
-It can participate in intracellular digestion of biomolecules.

Peroxisomes
Characteristics

small membrane-enclosed organelle which houses enzymes for multiple metabolic reactions

Peroxisomes
Function

-It participates in production and decomposition of H2O2.
-It performs oxidative reactions for molecules like uric acid, amino acids, and fatty acids.
-In plants, it facilitates glyoxylate cycle and photorespiration.

Water is found in ___

all cellular structures

Water vital for the

transfer of water-soluble (polar) substances via the blood as well as intra- and inter-cellular transfers.

water is very important in the physiologic regulation of temperature as water has

-high specific heat
-high heat conductivity
-high latent heat of evaporation

High specific heat

- enables energy storage without increasing body temp.

High heat conductivity

- allows heat transfer from body interior to body surface.

High latent heat of evaporation

- prevents quick evaporation resulting to overall cooling of body surface