Name: er in protein and lipid transport
Uploaded: 2026-06-01T06:27:54.229Z
Duration: 1 min 39 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Biology

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms- Structures and Processes

LS.Bio.1.3

Endoplasmic Reticulum

The endoplasmic reticulum, or ER, is an interconnected network of membranous sacs and tubules that is continuous with the outer nuclear membrane.One part of the ER, called the rough ER, gets its name from the ribosomes attached to its surface. When viewed under a microscope, these ribosomes give it a rough appearance.Bound ribosomes release newly synthesized proteins into the ER lumen, which is the space enclosed by the ER membrane. Inside the lumen, proteins fold into their three-dimensional shapes with the help of chaperone proteins. If the proteins fold correctly, they are packaged into vesicles and transported to the Golgi apparatus.Proteins that do not fold properly are returned to the cytosol for breakdown, and their amino acids are recycled.The other portion of the ER is called the smooth ER because it lacks bound ribosomes. This region synthesizes lipids and is involved in carbohydrate metabolism, which are packaged into vesicles or released through transporters on the ER membrane for delivery to other parts of the cell.In many eukaryotic cells, the smooth ER also stores calcium ions. In muscle cells, where it is called the sarcoplasmic reticulum, stored calcium ions are released to trigger muscle contraction.

endoplasmic reticulum

<h3>Endoplasmic Reticulum</h3>The endoplasmic reticulum (ER) is an extensive network of membranous sacs and tubules in eukaryotic cells, continuous with the outer membrane of the nucleus. This structural continuity integrates nuclear and cytoplasmic processes and facilitates efficient intracellular transport. This allows mRNA to move directly from the nucleus to ribosomes for efficient protein synthesis. As a result, the ER serves as a central site for the synthesis, processing, and distribution of biomolecules.Rough Endoplasmic Reticulum and Protein Processing The rough endoplasmic reticulum (RER) is characterized by ribosomes attached to its cytoplasmic surface. These ribosomes synthesize proteins that are translocated into the ER lumen, where they undergo folding into their functional three-dimensional conformations with the assistance of chaperone proteins. Properly folded proteins are packaged into transport vesicles and directed to the Golgi apparatus for further modification and sorting. Misfolded proteins are identified and transported back to the cytosol for degradation, ensuring quality control within the cell.Smooth Endoplasmic Reticulum and Lipid Synthesis The smooth endoplasmic reticulum (SER), lacking ribosomes, is primarily involved in the synthesis of lipids and carbohydrates. These molecules are either incorporated into membranes or transported to other cellular locations via vesicles or membrane-associated transport proteins. In liver cells, the smooth ER helps detoxify drugs and harmful substances.Calcium Storage and Specialized Functions In many eukaryotic cells, the SER also functions in calcium ion storage. In muscle cells, this specialized form is called the sarcoplasmic reticulum, where the regulated release of calcium ions is essential for muscle contraction.

https://cloudfront.jove.com/files/ftp_upload/10969/10969_article_thumb_10969.jpg

Education

JoVE Core

Cellular Processes

Cell Structure and Function

KEY TERMS AND CONCEPTS

er in protein and lipid transport

The endoplasmic reticulum is a membrane network in eukaryotic cells. It is continuous with the outer membrane of the nucleus. This connection helps link nuclear and cytoplasmic processes and supports efficient movement inside the cell. mRNA can move from the nucleus to ribosomes, which helps protein synthesis happen efficiently. The ER is a major site for making, processing, and distributing biomolecules.

The rough endoplasmic reticulum has ribosomes attached to its surface. These ribosomes make proteins that enter the ER lumen, or inner space. Inside the lumen, chaperone proteins help the new proteins fold into the correct three-dimensional shape. After folding, the proteins are packaged into transport vesicles and sent to the Golgi apparatus for more modification and sorting. If a protein is misfolded, it is sent back to the cytosol for degradation, which helps keep the cell’s proteins in working order.

The smooth endoplasmic reticulum does not have ribosomes. It mainly makes lipids and carbohydrates. These molecules can become part of membranes or move to other parts of the cell through vesicles or membrane-linked transport proteins. In liver cells, the smooth ER also helps detoxify drugs and other harmful substances.

In many eukaryotic cells, the smooth ER also stores calcium ions. In muscle cells, this specialized form is called the sarcoplasmic reticulum. There, the controlled release of calcium ions is essential for muscle contraction.

ER in Protein and Lipid Transport

what are cells?

Cell Membrane, DNA, and Organelles

Cells are the basic units of life, from a bacterium made of one cell to a human made of trillions. Even though organisms can differ greatly, their cells share key features that support life. A cell has a plasma membrane, which is a lipid bilayer that separates the cytoplasm from the outside environment. It also contains DNA, the genetic material that carries instructions for the cell. In prokaryotic cells, DNA is found in a region called the nucleoid. In eukaryotic cells, DNA is enclosed...

cell size

Why Cell Size Is Limited

Cell size is limited by surface area and diffusion. Cells vary widely in size, both between organisms and within the same organism. Bacterial cells are usually 1 to 10 micrometers wide, and the smallest bacteria can be 0.1 micrometers in diameter. That is about a thousand times smaller than most eukaryotic cells, which are typically 10 to 100 micrometers across. A cell takes in nutrients and water through diffusion across the plasma membrane or through channels in the membrane. The membrane...

prokaryotic cells

Prokaryotic Cell Structures

Prokaryotic cells are small, single-celled organisms found in the domains Archaea and Bacteria. Bacteria include familiar species such as Salmonella and E. coli. Archaea include extremophiles, which are organisms that live in harsh environments like volcanic springs. Prokaryotic cells share several basic features with eukaryotic cells. They are surrounded by a plasma membrane, contain cytoplasm, and have ribosomes that make proteins. Their genetic material is a single, circular DNA molecule.

eukaryotic compartmentalization

Cell Organelles and Microenvironments

Eukaryotic cells use membrane-bound organelles to keep cell processes organized. The nucleus and mitochondria are two key examples. Because biological membranes are selectively permeable, they create controlled spaces inside each organelle. These small microenvironments support specialized jobs and separate them from the surrounding cytosol. Different organelles maintain different internal conditions. In animal cells, lysosomes keep an acidic environment that helps their enzymes digest...

cytoplasm

Cytoplasm and the Cell’s Internal Framework

The cytoplasm is the cell’s internal space that holds organelles and the cytoskeleton. It is suspended in the cytosol, an aqueous fluid made of water, ions, salts, and many organic molecules. Together, these parts create the environment where key cell activities happen. The cytoplasm is also a major site for protein synthesis and folding. The water-based cytosol helps proteins fold correctly. Hydrophobic amino acid side chains tend to hide in the protein core, while hydrophilic amino acids...

the nucleus

Nuclear DNA and Cell Control

The nucleus is the control center of a eukaryotic cell. It is a membrane-bound organelle that contains chromosomal DNA. That DNA helps control gene expression and regulate protein production in the cell. Not all cellular DNA has the same role. The DNA in mitochondria and chloroplasts supports functions that are specific to those organelles. Inside the nucleus, DNA structure also affects how genes are regulated. Nuclear DNA is wrapped around proteins called histones. This forms chromatin, a...

The endoplasmic reticulum is a membrane network in eukaryotic cells. It is continuous with the outer membrane of the nucleus. This connection helps link nuclear and cytoplasmic processes and supports efficient movement inside the cell. mRNA can move from the nucleus to ribosomes, which helps protein synthesis happen efficiently. The ER is a major site for making, processing, and distributing biomolecules. The rough endoplasmic reticulum has ribosomes attached to its surface. These ribosomes...

ribosomes

How Ribosomes Build Proteins

Ribosomes build proteins by reading messenger RNA, or mRNA, and linking amino acids in the right order. Both prokaryotic and eukaryotic cells contain ribosomes. Cells that make large amounts of protein, such as secretory cells in the human pancreas, can have millions of them. Ribosomes are made of ribosomal RNA, or rRNA, and proteins. In eukaryotic cells, rRNA is transcribed from genes in the nucleolus, a part of the nucleus that specializes in making ribosomes. There, rRNA combines with...

golgi apparatus

Protein Sorting in the Golgi Apparatus

The Golgi apparatus sorts and modifies proteins after they leave the endoplasmic reticulum (ER). Properly folded and assembled proteins are packaged into vesicles, or small membrane sacs, and moved by microtubule-based motor proteins. These vesicles can fuse into vesicular tubular clusters before reaching the Golgi, which often looks like a ribbon-shaped organelle in eukaryotic cells. Vesicles enter the cis face of the Golgi, the side facing the ER. They pass through a set of pancake-shaped...

peroxisomes

Peroxisomes and Cellular Detoxification

Peroxisomes and mitochondria are two important oxygen-utilizing organelles in eukaryotic cells. Mitochondria carry out cellular respiration, which turns energy from food into ATP. Peroxisomes focus on breaking down substances such as fatty acids and other materials the cell needs to process. A peroxisome is a single membrane-bound organelle. It helps with lipid metabolism and chemical detoxification. Enzymes inside peroxisomes move hydrogen atoms from molecules to oxygen. This reaction...

microtubules

Microtubules in Cells and Cell Movement

Microtubules are cytoskeletal fibers that help cells keep their shape, move materials, and divide. They are the thickest of the three main cytoskeletal structures in eukaryotic cells, with a diameter of about 25 nm. Along with microfilaments and intermediate filaments, they form the internal support network of the cell. Microtubules are hollow tubes built from tubulin proteins. Each tubulin molecule is a heterodimer, which means it has two different parts: α-tubulin and β-tubulin. These dimers...

plant cell wall

Plant Cell Walls in Growth and Support

Plant cell walls help plant cells keep their shape, stay protected, and remain supported. As a cell matures, its wall can change based on the cell type. Parenchyma cells in leaves usually have only a thin primary cell wall. These walls are part of how different plant cells take on different jobs. Collenchyma and sclerenchyma cells are found mostly in the outer layers of stems and leaves. Collenchyma cells add strength by partially thickening the primary cell wall. Sclerenchyma cells provide...

plasmodesmata

Plasmodesmata and Plant Cell Communication

Plasmodesmata are the connections that let plant cells communicate directly. These tiny passageways link neighboring cells through the cell wall and help tissues work together in a multicellular plant. Cells in multicellular organisms must communicate to function as a unit. One way they do this is through intercellular junctions, which are contact points between adjacent cells. Fungal, plant, and animal cells all have intercellular junctions, but the types differ. In animal cells, the main...

the extracellular matrix

How ECM Supports Animal Tissues

The extracellular matrix (ECM) supports animal tissues by surrounding cells with structural molecules. It helps maintain tissue organization and gives tissues their specific physical properties. The ECM includes a gel-like ground substance, fibrous components, and many molecules with different jobs. A major part of the ECM is made of glycosaminoglycans, or GAGs. These polysaccharides fill much of the extracellular space and can take up a large volume for their mass. That makes the matrix...

gap junctions

Connexins and Cell-to-Cell Signaling

Gap junctions help animal cells send signals and share small materials with nearby cells. They are made of special proteins that form pores between neighboring cells and connect their cytoplasm. Through these channels, cells can exchange ions and other small molecules. These communication channels are found in many invertebrate and vertebrate species. They support important processes such as cell differentiation and development. They are also linked to human diseases, including disorders of...

tissues

Body Tissues and Their Jobs

Body tissues are groups of cells with similar structure and function. When different tissues work together, they form an organ with a specialized job. Vertebrates have four main tissue types: epithelial, connective, muscle, and nervous tissue. Epithelial tissue is made of thin sheets of cells. It covers the skin and lines internal organs and body cavities. These cells are tightly packed, so they help protect against injury, infection, and water loss. Epithelial tissue may be simple, with one...

key terms and concepts

Learn how the rough and smooth endoplasmic reticulum help cells make proteins, build lipids, store calcium, and support detoxification.

ER in Protein and Lipid Transport | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

Pennsylvania State Academic Standards

Life Science

Structure and Function

3.1.9-12.A

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Cells

Cell structure and function

Virginia  Standards of Learning

HIgh School

BIO.3

BIO.3.a

Arizona Science Standards

High School

HS+B.L1

HS+B.L1U1.4

Alabama Course of Study Science

From Molecules to Organisms: Structures and Processes

9-12.B.1.1

Florida Department of Education

SC.912.L.14

SC.912.L.14.2

SC.912.L.14.3

Compounds Essential to Human Function

The human body is composed of cells that are fundamentally made up of several different molecules. These molecules are essential to carry out all ...

Macromolecules

Biomolecules
Organisms contain a wide variety of organic molecules with numerous functions which depend on the chemical structures and properties of these ...

Solution Preparation
ExpandCAUTION: It is important to always use care when handling reagents. For example, iodine will stain clothes and skin so wear ...

Identifying Macromolecules with Indicator Solutions
ExpandHYPOTHESES: In this activity, the experimental hypothesis might be that the addition of an ...

pH Regulation in Cells

pH plays a critical role in maintaining normal cellular activities. It helps maintain the structure and function of various proteins, dictates the charge ...

Chemistry of the Cell

Overview of Functional Groups

Functional groups are a group of atoms with characteristic properties, which when linked to the carbon skeleton of a molecule, alter the properties of ...

Introduction to Carbohydrates

Carbohydrates, proteins, and fats are the primary macronutrients in the human diet. However, carbohydrates are the most favored source of energy in the ...

Carbohydrate Metabolism

Sugars as Energy Storage Molecules

What are Lipids?

lipid-derived-compounds-in-the-human-body

Lipid-derived Compounds in the Human Body

Fats and lipids are crucial components in the human body. Some lipid-derived compounds, such as fat-soluble vitamins, eicosanoids, lipoproteins, and ...

Fats as Energy Storage Molecules

What are Proteins?

Protein Organization

Globular Proteins

In organisms, proteins are the most abundant macromolecules. They act as the building blocks of life and play various crucial roles in the body. Proteins ...

Fibrous Proteins

Fibrous proteins are either long and narrow proteins or assemble to form long and thin structures. They contain repetitive units and usually consist of ...

Protein Denaturation

The function of proteins depends on their native three-dimensional structure, which is dictated by the amino acid sequence of the specific protein. ...

Role of Proteins in the Human Body

Proteins are the building block of life. They are also&#160; the most abundant macromolecules with as many diverse roles in the body. They are part of ...

Nucleic Acids and Nucleotides

Nucleic acids are the most important macromolecules for the continuity of life. They carry the cell&#39;s genetic blueprint and have instructions for its ...

Nucleic Acid Structure

The pentose sugar in DNA is deoxyribose, while in RNA the pentose sugar is ribose. The difference between the sugars is the presence of the hydroxyl group ...

ATP Energy Storage and Release

ATP and Macromolecule Synthesis

Biological macromolecules are organic compounds, predominantly composed of carbon atoms. The carbon atoms are covalently bonded with hydrogen, oxygen, ...

Construct an explanation to illustrate relationships between structure and function of major macromolecules essential for life.

LS.Bio.1.1

Introduction to Enzymes

The use of enzymes by humans dates to 7000 BCE. Humans first used enzymes to ferment sugars and produce alcohol without knowing that this was an ...

Enzymes and Activation Energy

The activation energy (or free energy of activation), abbreviated as Ea, is the small amount of energy input necessary for all chemical reactions to ...

Introduction to Enzyme Kinetics

Enzyme kinetics studies the rates of biochemical reactions. Scientists monitor the reaction rates for a particular enzymatic reaction at various substrate ...

Turnover Number and Catalytic Efficiency

The turnover number of an enzyme is the maximum number of substrate molecules it can transform per unit time. Turnover numbers for most enzymes range from ...

Catalytically Perfect Enzymes

The theory of catalytically perfect enzymes was first proposed by W.J. Albery and J. R. Knowles in 1976. These enzymes catalyze biochemical reactions at ...

introduction-to-mechanisms-of-enzyme-catalysis

Introduction to Mechanisms of Enzyme Catalysis

For many years, scientists thought that enzyme-substrate binding took place in a simple &#34;lock-and-key&#34; fashion. This model stated that the enzyme ...

Ligand Binding and Linkage

Cooperative Allosteric Transitions

Ribozymes

Carry out investigations to illustrate how enzymes act as catalysts for biochemical reactions and how environmental factors affect enzyme activity.

LS.Bio.1.2

What are Cells?

Cells are the smallest and basic units of life, whether it is a single cell that forms the entire organism, e.g., in a bacterium or trillions of them, ...

Cell Size

Cell sizes vary widely among and within organisms. Bacterial cells range between 1-10 micrometers (&#x3BC;m)and are considerably smaller than most ...

Eukaryotic Compartmentalization

One of the distinguishing features of eukaryotic cells is that they contain membrane-bound organelles, such as the nucleus and mitochondria, that carry ...

Prokaryotic Cells

Prokaryotes are small unicellular organisms that include the domains&#x2014;Archaea and Bacteria. Bacteria include many common organisms, such as ...

Cytoplasm

The cytoplasm consists of organelles and a framework of protein scaffolds called the cytoskeleton suspended in an aqueous solution, the cytosol. The ...

The Nucleus

The nucleus is a membrane-bound organelle that acts as a control center in a eukaryotic cell. It contains chromosomal DNA, which controls gene expression ...

Endoplasmic ReticulumThe endoplasmic reticulum (ER) is an extensive network of membranous sacs and tubules in eukaryotic cells, continuous with the outer ...

Ribosomes

Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that ...

Golgi Apparatus

As they leave the Endoplasmic Reticulum (ER), properly folded and assembled proteins are selectively packaged into vesicles. These vesicles are ...

Lysosomes

Lysosomes are membrane-enclosed spherical sacs derived from the Golgi apparatus. The most important function of the lysosome is degrading macromolecules ...

Peroxisomes

Peroxisomes and mitochondria are two important oxygen-utilizing organelles in eukaryotic cells. Mitochondria carry out cellular respiration&#x2014;the ...

Introduction to the Cytoskeleton

Overview of the Cytoskeleton
The cytoskeleton is a network of protein filaments present within the cell, having three distinct filaments ...

Introduction to Actin

Actin is a highly conserved cytoskeletal protein found abundantly in eukaryotic cells. It constitutes 10% weight of the total cellular protein in muscle ...

Cell Structure

Background
Cells represent the most basic biological units of all organisms, whether it be simple, single-celled organisms like bacteria, or large, ...

overview-of-myosin-structure-and-function

Overview of Myosin Structure and Function

Myosins are a family of molecular motor proteins, first identified in the skeletal muscles, where they are responsible for muscle contraction. Along with ...

Visualizing Onion and Cheek Cells
ExpandImmediately before the experiment, wash and peel onion bulbs for the class.
Remove the entire brown outer skin and ...

Microtubules

Microtubules are the thickest cytoskeletal filaments with a diameter of 25 nm. In prokaryotic organisms, microtubules are commonly found in locomotory ...

The Structure of Intermediate Filaments

The intermediate filaments are one of three widely studied cytoskeletal filaments. They are so named as their diameter (10 nm) is in between that of ...

Types of Intermediate Filaments

The intermediate filaments are an essential component of the cytoskeleton. Presently six types of intermediate filament have been identified. Type I and ...

Gap Junctions

Multicellular organisms employ a variety of ways for cells to communicate with each other. Gap junctions are specialized proteins that form pores between ...

The Extracellular Matrix

In order to maintain tissue organization, many animal cells are surrounded by structural molecules that make up the extracellular matrix (ECM). Together, ...

Tissues

Cells with similar structure and function are grouped into tissues. A group of tissues with a specialized function is called an organ. There are four main ...

Plant Cell Wall

The plant cell wall gives plant cells shape, support, and protection. As a cell matures, its cell wall specializes according to the cell type. For ...

Plasmodesmata

The organs in a multicellular organism&#x2019;s body are made up of tissues formed by cells. To work together cohesively, cells must communicate. One way ...

Use models to explain how the structure of organelles determines its function and supports overall cell processes.

Cells are the smallest and basic units of life, whether it is a single cell that forms the entire organism, e.g., in a bacterium, or trillions of them, ...

Construct explanations to compare prokaryotic and eukaryotic cells in terms of structures and degree of complexity.

LS.Bio.1.4

Analyze how the relationship between structure and function supports life processes within organisms.

ER in Protein and Lipid Transport

Description

Transcript

Tags

More videos by Standards