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Cell Parts and Functions

Part 1: The Cell Membrane

Definition

  • Also called Plasma membrane.

  • Plasma membrane has a double layer of phospholipid molecules.

  • A phospholipid molecule is made up of glycerol which is a phosphate group and two chains of fatty acid.

  • Protein molecules are also found embedded in phospholipids.

  • The membrane is composed of both protein and phospholipid molecules.    

  • Serves as the boundary between the outside environment and the inside of the cell.

  • Gives form and shape to the cells.

  • Connects one cell to two or more adjacent cells.

Functions

Osmosis

  • It is the spontaneous movement of solvent molecules through a semi-permeable (selective of what goes in and out) membrane.

  • The region of the higher solute concentration tends to equalize the lower solute concentration.

  • Is an essential process by means of which nutrients are delivered to the cells.

Diffusion

  • It is the movement of molecules from a region of high concentration to a region of low concentration.

Transporters

  • It lets nutrients enter the cell and by–products to leave the cell.

  • Sugar to glucose to energy

Endocytosis

  • It is the process in which cells absorb molecules by engulfing them.

  • The cell creates a small deformation inward called invagination.

Phagocytosis

  • Cell eating

Pinocytosis

  • Cell drinking

What is the difference between phagocytosis and pinocytosis? - QuoraExocytosis

  • It removes undigested residue of a substance brought in by endocytosis.

  • It also secretes substances such as hormones and enzymes.

  • Pathway

Exocytosis and Endocytosis ( Read ) | Biology | CK-12 Foundation

Part 2: Protoplasm and Organelles

Protoplasm

  • These are the plasma or mass of jelly-like materials inside the cell.

  • A protoplasm can change into a semisolid gel to semiliquid solution.

  • protoplasm:

    • proto = first

    • plasm = substance 

  • is divided in two forms

    • Liquid  

    • Jelly

Protoplasm is composed of:

  • 20% Carbon

  • 10% Hydrogen

  • 62% Oxygen

  • 3% nitrogen

  • 5% other elements.

Organelles

Major Organelles

  1. Mitochondria

Mitochondria - Definition, Function & Structure | Biology Dictionary

  • (singular: Mitochondrion)

  • These are the microscopic rod–shaped bodies in the cytoplasm.

  • They are the centers of cellular respiration, a process in which it produces energy–rich adenosine triphosphate (ATP)

  • ATP is a high – energy compound in cells that functions in energy storage and transfer.

  • If there is an absence of nucleus, Mitochondria takes over the place.

Ribosomes

  • All throughout the cytoplasm are tiny structures.

  • These organelles are composed of nucleic acid.

  • Made up of protein.
    Protein is synthesized produce in the ribosome

  • It serves as the site of biological protein synthesis or translation.

  • Ribosomes link amino acids together in the order specified by messenger RNA (mRNA) molecules.

  • Ribonucleic acid

  • Translation

    • Is the process in which ribosomes create proteins in the cytoplasm.

    • Ex. Ribosomes produce protein

  • Amino acids

    • Elements that are present are carbon, hydrogen, oxygen, and nitrogen.

    • It is important in biosynthesis.

    • It is the final product of protein digestion.

  • mRNA

    • It conveys genetic information from DNA

    • Function: delivers genetic information to DNA

  1. Endoplasmic Reticulum

  • It forms a network of tiny canals throughout the cell.

  • Function: transports the proteins and other molecules to other parts of the cell.

    Two types of Endoplasmic Reticulum:

    • Rough Endoplasmic Reticulum

    • Smooth Endoplasmic Reticulum

Rough Endoplasmic Reticulum - The School of Biomedical Sciences Wiki

  • Rough Endoplasmic Reticulum

    Function: the rough ER helps the proteins stay organized

  • Smooth Endoplasmic Reticulum

    Function: The main function of the smooth ER is synthesizing the lipids used in the cell membrane.

Packaging Counter of the Cell

  1. Golgi Bodies

  • It is the major collection and dispatch station of protein products received from the endoplasmic reticulum (ER).

  • Function: enhance the proteins and lipids, make secrete mucus, package product into vesicles for transport.

  • Proteins synthesized in the ER are packaged into vesicles which fuse with the Golgi apparatus.

  • The cargo proteins are modified and secreted via exocytosis.

  • Same as post office, Golgi Bodies package and label items which it then sends to different parts of the cells.

  • Function: move materials within the cell.

  • Structure of Golgi Bodies

    • Golgi Apparatus is made up of a series of compartments consisting of two networks:

      • Cis Golgi Network (CGN)

      • Trans Golgi Network (TGN)

  • CIS Golgi Network

    • Is a collection of fused, flattened membrane – enclosed cisternae, originating from a vesicular cluster that buds off the endoplasmic reticulum.

    • Entrance of proteins 

  • Trans Golgi Network

    • It is the final cisterna structure, from which protein are package into vesicles destined to: Lysosomes, Secretory vesicles, or the cell surface.

  • Exit of molecules (proteins).

Storage Tank of the Cell

  1. Vacuoles 

  • It is a membrane that is present in all plants and fungal cells. 

  • They are essentially enclosed compartments that are filled with water containing organic and inorganic molecules.

C:\Users\user\Desktop\general biology\fungal cell.jpg

The functions of the vacuole are:

  • Isolating materials that might be harmful or a threat to the cell.

  • Containing waste products

  • Containing water in plant cells

  • Allow plants to support structures such as leaves and flowers.

  • Plant Vacuole typically occupies more than 30% of the cell’s volume, and that can occupy as much as 80% of the volume for certain cell types and conditions.

  • Function: storage area for water, salts, proteins and carbohydrates.

  • A sac like structure.

Structure of a Vacuole

  • Tonoplast

    • Also known as vacuolar membrane.

    • A membrane that surrounds the vacuole.

    • It separates the vacuole content from the cytoplasm.

  • Cell sap

    • Water like content that fills the vacuole.

CentrAl VacUole (@centralvaCOOL) | Twitter

Suicide Bag of the Cell

  1. Lysosomes 

  • It acts as the waste disposal system of the cell by digesting the unwanted materials in the cytoplasm.

  • Function: to destroy any foreign material which enter the cell such as bacteria and virus, to protect the cells from infection

Cell Division

  1. Centrosomes

  • It is a mass of dense protoplasm with structures called centrioles at the center

  • Function: responsible for the regulation of cell division

  1. Centrioles

  • It is a part of the cytoplasm, duplicated and formed at the center for spindle fiber formation during the cell division.

  • Function: help with cell division, microtubules form spindle fibers for nuclear division.

Organelles Peculiar to plant cell

  1. Cell Wall

  • A structural layer surrounding some types of cells, located outside the cell membrane.

  • Provides both structural support and protection, and acts as a filtering mechanism.

Home | cellularcomponents

Structure of a cell wall

  • A cell wall has three layers:

    • Primary Cell Wall

    • Secondary Cell Wall

    • Middle Lamella

Primary Cell Wall

  • Generally, a thin, flexible and extensible layer forms while the cell is growing.

Secondary Cell Wall

  • A thick layer forms inside the primary cell wall after the cell is fully grown.

Middle Lamella

  • A layer rich in pectin.

  • This is the outermost layer that forms the interface between adjacent plant cells and glues them together.

  1. Pectin

  • It makes the cell strong.

  • But in fruits, the pectin loosens in the cell that results in softening of the fruit.

  1. Plastids

  • These are the large membrane – bound organelles found in the cytoplasm of plant cells.

  1. Chromoplasts

  • These are classified as the colored plastids.

    • Carotenoids

      • Various yellow or orange pigments.

      • These chromoplasts also may give flowers, ripened fruits, and autumn leaves their characteristic yellow or orange color.

    • Rhodoplast

      • Chromoplast with red pigment.

    • Leucoplast

      • These are the colorless plastids that serve as food storehouses in many plant cells.

      • They contain oil, starch grains, and proteins, as well as enzymes necessary to link glucose molecules together and form starch molecules.

  1. CHLOROPHYLL

  • Is very essential in the manufacture of food by green plants. 

Part 3: The Nucleus

Nucleus

  • Latin: Nuculeus – kernel or seed

  • Contains most of the cell’s genetic material, organized as multiple long layers of DNA molecules with a large variety of proteins to form chromosomes.

  • Function: The nucleus maintains the integrity of genes and controls the activities of the cell by regulating the genes expression.

Gene Expression

  • It is the process by which information from a gene is used in synthesis.

  • It involves transcription (DNA use as a template to produce RNA)

  • Using DNA code to create a protein that control a specific trait in expressing genetic information

Nuclear Envelope

  • Is composed of a phospholipid bilayer membrane (outer membrane and inner membrane) that encloses the entire organelle and isolates its contents from the cellular cytoplasm. Also called nucleus 

  • The nuclear envelope allows the nucleus to control its contents and separate them from the rest of the cytoplasm.

  • Function: Regulates the movement of molecules into and out of the cell.

Nuclear Pores

  • Helps to regulate nuclear transport of molecules across the envelope.

  • Function: Allows passage between the nucleus and cytoplasm.

Function of the Nucleus

  • The nucleus provides a site for genetic transcription.

  • Responsible for gene expression

  • Cell compartmentalization

  • Processing pre-mRNA (mRNA being exported to the cytoplasm)

Cell Function

  • All the life processes of a living cell involve transformation of energy and matter. 

A living cell performs the following life processes:

Nutrition

  • It is the process by which cells obtain food molecules to support their other activities.

Digestion

  • It is the process by which food particles are broken down into smaller soluble units suitable for cell use, with the help of enzymes.

Absorption

  • It is the process by which cells absorb water, minerals, and other materials essential to life from their environment.

Movement

  • It is the process which includes the locomotion of cells by means of special structures like cilia and flagella.

Difference between Cilia and Flagella Explained -

Irritability

  • How cells respond or react to external factors or conditions around them.

  • Cells can alter their functions in response to changes in their environment.

Respiration

  • It is the process of breaking down food molecules into chemical energy needed by all cells in order to function.

Reproduction

  • It is a process by which a cell copies or replicates its DNA and increases its number by cell division. In reproduction, cells give rise to new cells.

Additional Facts

  • Ribosomes are the most important organelles

  • Remember the size of large virus and bacteria

  • Prokaryotes are the simplest cellular organisms

  • Flagella (flagellum) is longer that pili (pilus)

  • Genetic material is not separated from the cytoplasm

  • Cytoskeleton is the framework for cells

  • Distinguishing characteristic of eukaryotic cell is the NUCLEUS

  • In eukaryotic, each compartment can provide specific conditions favoring a particular process

  • Chromatin is found if cell is not dividing

  • Chromosomes (the membranes are removed) in cell division

  • Golgi complex, Golgi apparatus, Golgi bodies

  • Plasma membrane is conceptualized as fluid mosaic model (patches because of proteins)

  • Endocrine glands are ductless, hormones pass through blood streams

  • Cell service proteins that serve as markers for them to know their target destinations

  • Cholesterol affects the fluidity of cells

  • Nuclear surface is perforated with nuclear pores for passage between nucleus and cytoplasm

  • Ribosomes in the cytoplasm only make proteins for its cell

  • Ribosomes from the ER make proteins for its neighboring cells.

  • Pathogens are invaders

  • Lysosomes are single membrane

  • Mitochondria and chloroplasts have double membrane

  • Study parts of plant cell from the ppt

  • Symbiosis – two organism benefit from each other

  • Endosymbiosis – single membraned ancient bacteria enter pre-eukaryotic cell and transform into mitochondria and chloroplast

  • Ancient bacteria will have habitat. They will have sugar, lipids, and proteins as their benefit in the symbiosis.

  • Meanwhile, pre-eukaryotic cell will benefit from the created mitochondrion and chloroplast 

  • Actin filament (microfilament) is the thinnest

  • Intermediate filament if the thickest

M

Cell Parts and Functions

Part 1: The Cell Membrane

Definition

  • Also called Plasma membrane.

  • Plasma membrane has a double layer of phospholipid molecules.

  • A phospholipid molecule is made up of glycerol which is a phosphate group and two chains of fatty acid.

  • Protein molecules are also found embedded in phospholipids.

  • The membrane is composed of both protein and phospholipid molecules.    

  • Serves as the boundary between the outside environment and the inside of the cell.

  • Gives form and shape to the cells.

  • Connects one cell to two or more adjacent cells.

Functions

Osmosis

  • It is the spontaneous movement of solvent molecules through a semi-permeable (selective of what goes in and out) membrane.

  • The region of the higher solute concentration tends to equalize the lower solute concentration.

  • Is an essential process by means of which nutrients are delivered to the cells.

Diffusion

  • It is the movement of molecules from a region of high concentration to a region of low concentration.

Transporters

  • It lets nutrients enter the cell and by–products to leave the cell.

  • Sugar to glucose to energy

Endocytosis

  • It is the process in which cells absorb molecules by engulfing them.

  • The cell creates a small deformation inward called invagination.

Phagocytosis

  • Cell eating

Pinocytosis

  • Cell drinking

What is the difference between phagocytosis and pinocytosis? - QuoraExocytosis

  • It removes undigested residue of a substance brought in by endocytosis.

  • It also secretes substances such as hormones and enzymes.

  • Pathway

Exocytosis and Endocytosis ( Read ) | Biology | CK-12 Foundation

Part 2: Protoplasm and Organelles

Protoplasm

  • These are the plasma or mass of jelly-like materials inside the cell.

  • A protoplasm can change into a semisolid gel to semiliquid solution.

  • protoplasm:

    • proto = first

    • plasm = substance 

  • is divided in two forms

    • Liquid  

    • Jelly

Protoplasm is composed of:

  • 20% Carbon

  • 10% Hydrogen

  • 62% Oxygen

  • 3% nitrogen

  • 5% other elements.

Organelles

Major Organelles

  1. Mitochondria

Mitochondria - Definition, Function & Structure | Biology Dictionary

  • (singular: Mitochondrion)

  • These are the microscopic rod–shaped bodies in the cytoplasm.

  • They are the centers of cellular respiration, a process in which it produces energy–rich adenosine triphosphate (ATP)

  • ATP is a high – energy compound in cells that functions in energy storage and transfer.

  • If there is an absence of nucleus, Mitochondria takes over the place.

Ribosomes

  • All throughout the cytoplasm are tiny structures.

  • These organelles are composed of nucleic acid.

  • Made up of protein.
    Protein is synthesized produce in the ribosome

  • It serves as the site of biological protein synthesis or translation.

  • Ribosomes link amino acids together in the order specified by messenger RNA (mRNA) molecules.

  • Ribonucleic acid

  • Translation

    • Is the process in which ribosomes create proteins in the cytoplasm.

    • Ex. Ribosomes produce protein

  • Amino acids

    • Elements that are present are carbon, hydrogen, oxygen, and nitrogen.

    • It is important in biosynthesis.

    • It is the final product of protein digestion.

  • mRNA

    • It conveys genetic information from DNA

    • Function: delivers genetic information to DNA

  1. Endoplasmic Reticulum

  • It forms a network of tiny canals throughout the cell.

  • Function: transports the proteins and other molecules to other parts of the cell.

    Two types of Endoplasmic Reticulum:

    • Rough Endoplasmic Reticulum

    • Smooth Endoplasmic Reticulum

Rough Endoplasmic Reticulum - The School of Biomedical Sciences Wiki

  • Rough Endoplasmic Reticulum

    Function: the rough ER helps the proteins stay organized

  • Smooth Endoplasmic Reticulum

    Function: The main function of the smooth ER is synthesizing the lipids used in the cell membrane.

Packaging Counter of the Cell

  1. Golgi Bodies

  • It is the major collection and dispatch station of protein products received from the endoplasmic reticulum (ER).

  • Function: enhance the proteins and lipids, make secrete mucus, package product into vesicles for transport.

  • Proteins synthesized in the ER are packaged into vesicles which fuse with the Golgi apparatus.

  • The cargo proteins are modified and secreted via exocytosis.

  • Same as post office, Golgi Bodies package and label items which it then sends to different parts of the cells.

  • Function: move materials within the cell.

  • Structure of Golgi Bodies

    • Golgi Apparatus is made up of a series of compartments consisting of two networks:

      • Cis Golgi Network (CGN)

      • Trans Golgi Network (TGN)

  • CIS Golgi Network

    • Is a collection of fused, flattened membrane – enclosed cisternae, originating from a vesicular cluster that buds off the endoplasmic reticulum.

    • Entrance of proteins 

  • Trans Golgi Network

    • It is the final cisterna structure, from which protein are package into vesicles destined to: Lysosomes, Secretory vesicles, or the cell surface.

  • Exit of molecules (proteins).

Storage Tank of the Cell

  1. Vacuoles 

  • It is a membrane that is present in all plants and fungal cells. 

  • They are essentially enclosed compartments that are filled with water containing organic and inorganic molecules.

C:\Users\user\Desktop\general biology\fungal cell.jpg

The functions of the vacuole are:

  • Isolating materials that might be harmful or a threat to the cell.

  • Containing waste products

  • Containing water in plant cells

  • Allow plants to support structures such as leaves and flowers.

  • Plant Vacuole typically occupies more than 30% of the cell’s volume, and that can occupy as much as 80% of the volume for certain cell types and conditions.

  • Function: storage area for water, salts, proteins and carbohydrates.

  • A sac like structure.

Structure of a Vacuole

  • Tonoplast

    • Also known as vacuolar membrane.

    • A membrane that surrounds the vacuole.

    • It separates the vacuole content from the cytoplasm.

  • Cell sap

    • Water like content that fills the vacuole.

CentrAl VacUole (@centralvaCOOL) | Twitter

Suicide Bag of the Cell

  1. Lysosomes 

  • It acts as the waste disposal system of the cell by digesting the unwanted materials in the cytoplasm.

  • Function: to destroy any foreign material which enter the cell such as bacteria and virus, to protect the cells from infection

Cell Division

  1. Centrosomes

  • It is a mass of dense protoplasm with structures called centrioles at the center

  • Function: responsible for the regulation of cell division

  1. Centrioles

  • It is a part of the cytoplasm, duplicated and formed at the center for spindle fiber formation during the cell division.

  • Function: help with cell division, microtubules form spindle fibers for nuclear division.

Organelles Peculiar to plant cell

  1. Cell Wall

  • A structural layer surrounding some types of cells, located outside the cell membrane.

  • Provides both structural support and protection, and acts as a filtering mechanism.

Home | cellularcomponents

Structure of a cell wall

  • A cell wall has three layers:

    • Primary Cell Wall

    • Secondary Cell Wall

    • Middle Lamella

Primary Cell Wall

  • Generally, a thin, flexible and extensible layer forms while the cell is growing.

Secondary Cell Wall

  • A thick layer forms inside the primary cell wall after the cell is fully grown.

Middle Lamella

  • A layer rich in pectin.

  • This is the outermost layer that forms the interface between adjacent plant cells and glues them together.

  1. Pectin

  • It makes the cell strong.

  • But in fruits, the pectin loosens in the cell that results in softening of the fruit.

  1. Plastids

  • These are the large membrane – bound organelles found in the cytoplasm of plant cells.

  1. Chromoplasts

  • These are classified as the colored plastids.

    • Carotenoids

      • Various yellow or orange pigments.

      • These chromoplasts also may give flowers, ripened fruits, and autumn leaves their characteristic yellow or orange color.

    • Rhodoplast

      • Chromoplast with red pigment.

    • Leucoplast

      • These are the colorless plastids that serve as food storehouses in many plant cells.

      • They contain oil, starch grains, and proteins, as well as enzymes necessary to link glucose molecules together and form starch molecules.

  1. CHLOROPHYLL

  • Is very essential in the manufacture of food by green plants. 

Part 3: The Nucleus

Nucleus

  • Latin: Nuculeus – kernel or seed

  • Contains most of the cell’s genetic material, organized as multiple long layers of DNA molecules with a large variety of proteins to form chromosomes.

  • Function: The nucleus maintains the integrity of genes and controls the activities of the cell by regulating the genes expression.

Gene Expression

  • It is the process by which information from a gene is used in synthesis.

  • It involves transcription (DNA use as a template to produce RNA)

  • Using DNA code to create a protein that control a specific trait in expressing genetic information

Nuclear Envelope

  • Is composed of a phospholipid bilayer membrane (outer membrane and inner membrane) that encloses the entire organelle and isolates its contents from the cellular cytoplasm. Also called nucleus 

  • The nuclear envelope allows the nucleus to control its contents and separate them from the rest of the cytoplasm.

  • Function: Regulates the movement of molecules into and out of the cell.

Nuclear Pores

  • Helps to regulate nuclear transport of molecules across the envelope.

  • Function: Allows passage between the nucleus and cytoplasm.

Function of the Nucleus

  • The nucleus provides a site for genetic transcription.

  • Responsible for gene expression

  • Cell compartmentalization

  • Processing pre-mRNA (mRNA being exported to the cytoplasm)

Cell Function

  • All the life processes of a living cell involve transformation of energy and matter. 

A living cell performs the following life processes:

Nutrition

  • It is the process by which cells obtain food molecules to support their other activities.

Digestion

  • It is the process by which food particles are broken down into smaller soluble units suitable for cell use, with the help of enzymes.

Absorption

  • It is the process by which cells absorb water, minerals, and other materials essential to life from their environment.

Movement

  • It is the process which includes the locomotion of cells by means of special structures like cilia and flagella.

Difference between Cilia and Flagella Explained -

Irritability

  • How cells respond or react to external factors or conditions around them.

  • Cells can alter their functions in response to changes in their environment.

Respiration

  • It is the process of breaking down food molecules into chemical energy needed by all cells in order to function.

Reproduction

  • It is a process by which a cell copies or replicates its DNA and increases its number by cell division. In reproduction, cells give rise to new cells.

Additional Facts

  • Ribosomes are the most important organelles

  • Remember the size of large virus and bacteria

  • Prokaryotes are the simplest cellular organisms

  • Flagella (flagellum) is longer that pili (pilus)

  • Genetic material is not separated from the cytoplasm

  • Cytoskeleton is the framework for cells

  • Distinguishing characteristic of eukaryotic cell is the NUCLEUS

  • In eukaryotic, each compartment can provide specific conditions favoring a particular process

  • Chromatin is found if cell is not dividing

  • Chromosomes (the membranes are removed) in cell division

  • Golgi complex, Golgi apparatus, Golgi bodies

  • Plasma membrane is conceptualized as fluid mosaic model (patches because of proteins)

  • Endocrine glands are ductless, hormones pass through blood streams

  • Cell service proteins that serve as markers for them to know their target destinations

  • Cholesterol affects the fluidity of cells

  • Nuclear surface is perforated with nuclear pores for passage between nucleus and cytoplasm

  • Ribosomes in the cytoplasm only make proteins for its cell

  • Ribosomes from the ER make proteins for its neighboring cells.

  • Pathogens are invaders

  • Lysosomes are single membrane

  • Mitochondria and chloroplasts have double membrane

  • Study parts of plant cell from the ppt

  • Symbiosis – two organism benefit from each other

  • Endosymbiosis – single membraned ancient bacteria enter pre-eukaryotic cell and transform into mitochondria and chloroplast

  • Ancient bacteria will have habitat. They will have sugar, lipids, and proteins as their benefit in the symbiosis.

  • Meanwhile, pre-eukaryotic cell will benefit from the created mitochondrion and chloroplast 

  • Actin filament (microfilament) is the thinnest

  • Intermediate filament if the thickest