[BIOLOGY] The Cell Pt 1

Anton van Leeuwenhoek

a Dutch scientist known for his works with microscopy and considered one of the pillars of microbiology

Anton van Leeuwenhoek

universally acknowledged as the father of microbiology.

Robert Hooke

who first observed and coined the term cell

honeycomb shape

what shape did Robert Hooke saw when he observed the cell

Cell Theory

the idea that living organisms are composed of basic, structural units called cells.

1. All living organisms are composed of one or many cells.
2. Cells are the basic unit of structure and organization in organisms.
3. Cells must come from pre-existing cells.

Three main ideas of Cell Theory

1. DNA is passed between cells during cell division.
2. All cells of organisms have the same basic chemical composition.
3. Energy flow occurs within cells.

Three added ideas to the Modern Cell Theory

1. Plasma Membrane
2. Cytosol
3. Chromosomes
4. Ribosomes

All cells share four common components, namely…

plasma membrane

serves as an outer covering that protects the insides of a cell from its surrounding environment

phospholipids bilayer

plasma membrane is commonly composed of ________

**Cytosol** 

a fluid region in the cell where other cell components are found

Chromosomes

structures that contain genetic material in the form of DNA

Ribosomes

particles that synthesize proteins

Plasma Membrane

A semi-permeable layer that separates the insides of a cell from the external environment and is the location of chemical exchanges for many life functions.

Cytoplasm

The fluid internal environment of the cell where all internal components of the cell (called “organelles”) are suspended

Nucleus

Stores the genetic material of the cell. In prokaryotes

Nucleoid

where is the genetic material located

Nuclear Membrane

Encloses the nucleus and protects the genetic material.

Nucleoplasm

The environment within the nucleus.

Nucleolus

An area in the nucleoplasm where the genetic material is highly concentrated.

Nuclear Pore

Gateway of materials into or out of the nucleus.

Mitochondrion

Produces energy for the organism, having the moniker “powerhouse of the cell” due to this function.

Endoplasmic Reticulum (ER)

Sites for lipid and protein synthesis.

Rough ER

Contains ribosomes and is the site for protein synthesis. In addition, it also functions as the cell’s membrane-making machine.

**Smooth ER**

\

Contains cell types used in metabolic processes, especially lipid synthesis, as well as storage of calcium ions.

Golgi Apparatus

Site for modifying, sorting, and storing compounds synthesized by the ER.

Lysosome

Contains digestive enzymes that help break down food or damaged organelles.

Peroxisome

Helps break down fatty acids to be used as cellular fuel.

Ribosome

Can be found attached to the rough ER or free in the cytosol

Vacuoles

Storage of food and other chemicals.

Centriole

Organelle for cell division.

chloroplasts

present in plants and used in photosynthesis.

Prokaryotes

refer to organisms with cells that are simple, often single (unicellular), and **lack a nucleus**, or any other **membrane-bound organelle**.

nucleoid

Prokaryotic DNA is found in the central part of the cell: a darkened region called the

peptidoglycan

a cell wall of bacteria composed of sugars and amino acids, and many have a polysaccharide capsule

peptidoglycan

the cell wall of bacteria that acts as an extra layer of protection, helping the cell maintain its shape, and preventing dehydration.

capsule

another part of procaryote cell that allows the cell to attach to surfaces in its environment

flagella

part of prokaryote cell that is used for locomotion

pili

used to exchange genetic material during a type of reproduction called conjugation.

eukaryote

meanwhile, is composed of cells that have a membrane-bound nucleus and other membrane-bound compartments, called organelles, with specialized functions.

true nucleus

The word eukaryotic means

little organ

 The word “organelle” means

1. Genetic Control
2. Manufacture, distribution, and breakdown of molecules
3. Energy processing
4. Structural support, movement, and communication

groups of organelles based on function

nucleus and ribosomes

part of the genetic control group

1. Endoplasmic reticulum
2. Golgi apparatus
3. lysosomes
4. vacuoles
5. peroxisomes

tasked for the Manufacture, distribution, and breakdown of molecules

mitochondria and chloroplasts

Energy processing group

1. cytoskeleton
2. plasma membrane
3. plant cell wall

tasked for the Structural support, movement, and communication between cells

plasmodesmata

Unique structures that connect adjacent plant cells

chloroplast

part of plant cell where photosynthesis occures

cytoskeleton

the Networks of protein fibers that provide structural support as well as movement

1. Microtubules
2. Intermediate filaments
3. Microfilaments

Three main kinds of fibers that make up the cytoskeleton

Microtubules

straight and hollow tubes composed of proteins called tubulins.

Microtubules

In animal cells, these grow from the centrosome while plant cells have other means of synthesizing as they lack centrosomes.

**Intermediate filaments** 

found in cells of most animals, these reinforce cell shape and anchor some organelles. For example, the outer layer of our skin is made of dead skin cells composed of these

Microfilaments

help support the cell’s shape, particularly in animal cells that lack cell walls. These are also involved in cell movements.

actin filaments

Microfilaments are also called ____

cilia

short and numerous appendages that propel the protist *Paramecium*.

flagellum

is longer than the cilia but present in fewer numbers or as a sole structure per cell.

extracellular matrix (ECM)

Animal cells produce what that helps hold cells together and protects and supports the plasma membrane

glycoproteins

the main components of extracellular matrix (ECM) are

glycoproteins

are proteins bonded with carbohydrates.

1. Tight Junctions
2. Anchoring Junctions
3. Gap junctions

3 types of junctions

Tight Junction

a type of junction that occurs when the plasma membrane of neighboring cells is knit tightly together by proteins.

Tight Junction

Anchoring junctions

fasten cells into strong sheets. These junctions are connected to the cytoplasm by intermediate filaments.

Tight junctions

They prevent the leakage of fluid across a layer of cells. For example, the food we eat and are within our digestive tract does not leak because of these cell junctions.

Anchoring junctions

These junctions are common in tissues subjected often to stretching such as our skin and muscle.

Anchoring junctions

Gap junctions

also called communicating junctions

Gap junctions

this type of junction allows small molecules to flow through protein-lined pores between cells.

Gap junctions

this junction is common in babies in the womb since communication between the mother and the developing baby is necessary for the baby’s development.

Gap junctions

pectin

Plant cells initially lay down a relatively thin and flexible primary wall to allow the cell to continue to enlarge. Between adjacent cells is a sticky substance called _______, gluing cells together. When the plant cell stops growing, it strengthens the wall.

plasmodesmata

it allows water and other small molecules to freely move from cell to cell. These structures allow cells in plant tissues to share water, nourishment, and chemical messages.