Name: lipids, fats, and cell membranes
Uploaded: 2020-09-24T15:06:53.000Z
Duration: 3 min 38 s
Channel: JoVE

K12 Standards

Next Generation Science Standards

High School

Life Science

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

From Molecules to Organisms: Structures and Processes

HS-LS1-6

Structure of Lipids

Lipitler, enerji depolamak için kullanılan trigliseridleri ve hücre zarlarının ana yapısal bileşenleri olan fosfolipidleri içeren bir grup hidrofobik moleküldür. Trigliseritler ve çoğu fosfolipid, gliserol ve yağ asidi zincirlerinden oluşur. Yağ asitleri, zincirin bir ucunda metil gruplarına ve diğer ucunda karboksil gruplarına sahiptir.Karboksil grubuna bağlı karbon, alfa karbon olarak adlandırılır ve metil grubu karbon, omega karbon olarak bilinir. Yağ asitlerinin uzunluğu ve hidrokarbon zincirinde çift bağların varlığı değişir. Çift bağlı olanlar doymamış yağ asitleridir ve sadece tek bağa sahip olanlar doymuş yağ asitleridir çünkü mümkün olan en fazla sayıda hidrojen atomu ile doymuşlardır.Yağ asitlerinin genellikle ortak adları vardır, ancak karbon atomlarının sayısına ve karbon zincirindeki çift bağların sayısına ve konumuna göre sistematik olarak adlandırılabilir. Birkaç yaygın numaralandırma yöntemi vardır. Karboksil referanslama sistemi, 1 olarak numaralandırılan karbonil karbondan tüm çift bağların konumunu sayar.Omega referans sistemi, omega karbonu 1 olarak numaralandırılmış omega karbona en yakın çift bağın konumunu sayar. Örneğin, bir omega 3 yağ asidi olan linolenik asit, karboksil ucundan sayımdan itibaren 9, 12 ve 15 konumlarında 18 karbona ve çift bağa sahiptir. Bu, karboksil referanslama sistemine göre 8:3 Δ9, 12, 15 ve omega referans sistemine göre 18:3 olarak adlandırılmaktadır.Doymamış yağ asitleri iki konfigürasyonda ortaya çıkabilir:cis ve trans. Cis konfigürasyonunda, çift bağda yer alan karbonlar üzerindeki hidrojenler, bağın aynı tarafındadır, halbuki trans konfigürasyonunda, hidrojenler zıt taraflarda yer almaktadır. Yapısal olarak cis yağ asitleri bükülmüş zincirlere sahipken, trans yağ asitleri düz zincirlere sahiptir.Trans yağ tüketiminin çeşitli kardiyovasküler hastalıklardan sorumlu olduğu bulunmuştur, oysa omega-3 ve omega-6 gibi cis yağ asitlerinin tüketiminin sağlığa faydalı olduğu bilinmektedir. Yaygın olarak yağ olarak bilinen trigliseridler, öncelikle enerji depolamak için kullanılır. Gliserolün hidroksil uçları ile yağ asitlerinin karboksil uçları arasındaki ester bağları yoluyla gliserole bağlanan üç yağ asidinden oluşurlar ve bu da polar olmayan bir molekül oluşumuna neden olur.Üç yağ asidi de aynı türdeyse, basit trigliseritler olarak bilinirler. Üç yağ asidi farklıysa, bunlar karışık trigliseritler olarak bilinirler. Diğer bir lipit türü olan fosfolipitler, biyolojik zarların önemli bir yapısal özelliğidir.Bir hidrofilik alkol grubu ve hidrofobik yağ asidi kuyrukları ile modifiye edilmiş fosfat gruplarından oluşan hidrofilik kafalara sahiptirler. Bu başlıkların ve kuyrukların bileşimi değişebilir, bu da farklı tipte membran lipidlerine neden olur. Gliserofosfolipidler, sırasıyla ester ve fosfodiester bağları yoluyla her gliserol karbonuna bağlanan iki yağ asidi ve oldukça polar bir gruptan oluşan yaygın bir fosfolipid türüdür.

lipidlerin yapısı

Lipitler, doğada büyük ölçüde apolar olan çeşitli bileşikler grubunu içerir. Bunun nedeni, çoğunlukla polar olmayan karbon-karbon veya karbon-hidrojen bağlarını içeren hidrokarbonlardır. Polar olmayan moleküller hidrofobiktir ('su korkusu') veya suda çözünmez. Lipitler bir hücrede birçok farklı işlevi yerine getirir. Hücreler, yağ şeklinde uzun süreli kullanım için enerji depolar. Lipitler ayrıca bitkiler ve hayvanlar için çevreden yalıtım sağlar. Örneğin, su, itici hidrofobik doğası nedeniyle kürk veya tüyler üzerinde koruyucu bir tabaka oluştururken suda yaşayan kuşların ve memelilerin kuru kalmasına yardımcı olurlar. Lipitler ayrıca birçok hormonun yapı taşlarıdır ve tüm hücre zarlarının önemli bir bileşenidir. Lipitler arasında yağlar, sıvı yağlar, mumlar, fosfolipitler ve steroidler bulunur.
 
 Lipitlerin Genel Yapısı
 
 Bir yağ molekülü iki ana bileşenden oluşur-gliserol ve yağ asitleri. Gliserol, üç karbon, beş hidrojen ve üç hidroksil (OH) grubuna sahip organik bir bileşiktir (alkol). Yağ asitleri, bir karboksil grubunun bağlı olduğu uzun bir hidrokarbon zincirine sahiptir, bu nedenle 'yağ asidi' olarak adlandırılır. Yağ asidindeki karbon sayısı 4 ila 36 arasında değişebilir. En yaygın olanları 12-18 karbon içerenlerdir. Bir yağ molekülünde, yağ asitleri gliserol molekülünün üç karbonunun her birine bir oksijen atomu yoluyla bir ester bağı ile bağlanır. Bir dehidrasyon reaksiyonunda üç yağ asidinin bir gliserol omurgasına katılması triasilgliserol oluşturur. Triasilgliseroldeki üç yağ asidi benzer veya farklı olabilir.
 
 Bir fosfolipid başka bir yaygın lipit türüdür. Amfipatik bir moleküldür, yani hidrofobik ve hidrofilik bir kısmı vardır. Yağ asidi zincirleri hidrofobiktir ve su ile etkileşime giremez; oysa fosfat içeren grup hidrofiliktir ve su ile etkileşime girer. Fosfolipidlerin hidrofilik kafa grupları sulu çözelti ile karşı karşıyadır. Hidrofobik kuyruklar iki tabakanın ortasında tutulur.
 
 Yağ Asitleri
 
 Yağ asitleri doymuş veya doymamış olabilir. Bir yağ asidi zincirinde, hidrokarbon zincirindeki komşu karbonlar arasında sadece tek bağlar varsa, yağ asidi doyurulur. Stearik asit, doymuş yağ asidinin bir örneğidir.
 
 Hidrokarbon zinciri bir çift bağ içerdiğinde, yağ asidi doymamış olur. Oleik asit, doymamış bir yağ asidi örneğidir. Doymamış yağların çoğu oda sıcaklığında sıvıdır ve yağ olarak adlandırılır. Molekülde bir çift bağ varsa, o zaman tekli doymamış bir yağdır (örneğin, zeytinyağı). Birden fazla çift bağ varsa, o zaman çoklu doymamış bir yağdır (örneğin, kanola yağı). Tek bağlara sahip uzun düz yağ asitleri genellikle sıkıca paketlenir ve oda sıcaklığında katıdır. Stearik asit ve palmitik asit içeren hayvansal yağlar (ette yaygın olarak bulunur) ve bütirik asit içeren yağlar (tereyağında yaygın olarak bulunur) doymuş yağ örnekleridir.
 
 Yağ asitleri ayrıca Cis ve trans olarak sınıflandırılabilir. Cis ve trans, molekülün çift bağ etrafındaki konfigürasyonunu gösterir. Hidrojenler aynı düzlemde mevcutsa, bir cis yağıdır. Hidrojen atomları iki farklı düzlemde ise, bir trans yağdır. cis çift bağı, yağ asitlerinin sıkıca paketlenmesini önleyen ve oda sıcaklığında sıvı tutan bir bükülme veya 'kıvrılmaya' neden olur. Zeytinyağı, mısır yağı, kanola yağı ve morina karaciğeri yağı doymamış yağlara örnektir. Doymamış yağlar kandaki kolesterol seviyesini düşürmeye yardımcı olurken, doymuş yağlar arterlerde plak oluşumuna katkıda bulunur.
 
 Trans Yağlar
 
 Gıda endüstrisi, yağları yarı katı ve birçok işlenmiş gıda ürünü için arzu edilen bir kıvamda yapmak için yapay olarak hidrojene eder. Bu işlem sırasında, hidrokarbon zincirindeki cis– konformasyonun çift bağları,trans– konformasyonda çift bağlara dönüşebilir.
 
 Margarin, bazı fıstık ezmesi türleri ve kısaltma yapay olarak hidrojene trans yağların örnekleridir. Son çalışmalar, insan diyetindeki trans yağlardaki bir artışın, düşük yoğunluklu lipoproteinlerin (LDL) veya 'kötü' kolesterolün daha yüksek seviyelerine yol açabileceğini ve bunun da arterlerde plak birikmesine ve kalp hastalığına yol açabileceğini göstermiştir.
 
 Omega Yağ Asitleri
 
 Esansiyel yağ asitleri, insan vücudunun ihtiyaç duyduğu ancak sentezlemediği asitlerdir. Sonuçta, diyette yutma yoluyla takviye edilmelidir. Omega-3 yağ asitleri bu kategoriye girer ve insanlar için bilinen sadece iki taneden biridir (diğeri omega-6 yağ asididir). Bunlar çoklu doymamış yağ asitleridir ve omega-3'tür, çünkü çift bağ üçüncü karbonu hidrokarbon zincirinin ucundan komşu karbona bağlar.
 
 Alfa-linolenik asit, bir omega-3 yağ asidi örneğidir. Üç cis çift bağa ve sonuç olarak kavisli bir şekle sahiptir. Somon, alabalık ve ton balığı, omega-3 yağ asitlerinin iyi kaynaklarıdır. Araştırmalar, omega-3 yağ asitlerinin kalp krizlerinden ani ölüm riskini azalttığını, kandaki trigliseritleri düşürdüğünü, kan basıncını düşürdüğünü ve kan pıhtılaşmasını inhibe ederek trombozu önlediğini göstermektedir. Ayrıca iltihaplanmayı azaltır ve hayvanlarda bazı kanser riskini azaltmaya yardımcı olabilirler.
 
 Bu metin bu kaynaktan uyarlanmıştır: <a href="https://openstax.org/books/biology-2e/pages/3-3-lipids">Openstax, Biology 2e, Chapter 3.3: Lipids</a>.

Lipidlerin Yapısı

Lipitler, doğası gereği büyük ölçüde polar olmayan çeşitli bileşikler içerir. Bunun nedeni, çoğunlukla polar olmayan hidrokarbonlar olmalarıdır ...

Education

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Biochemistry

Biyokimya

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

lipids, fats, and cell membranes

Lipids are nonpolar molecules that do not mix well with water. They are hydrophobic, which means “water fearing,” because they contain mostly nonpolar carbon-carbon and carbon-hydrogen bonds. In cells, lipids store long-term energy as fats, help insulate plants and animals, and form protective water-repellent layers on feathers and fur. They are also part of cell membranes and serve as building blocks for many hormones. Common lipids include fats, oils, waxes, phospholipids, and steroids.

A fat molecule is built from glycerol and fatty acids. Glycerol is an alcohol with three carbons, five hydrogens, and three hydroxyl groups. Fatty acids have a long hydrocarbon chain with a carboxyl group attached. Their chains can range from 4 to 36 carbons, but 12 to 18 carbons is most common. In a fat, three fatty acids join to one glycerol backbone through ester bonds in a dehydration reaction. This forms a triacylglycerol. The three fatty acids may be the same or different.

Phospholipids are another major lipid type. They are amphipathic, which means they have both a hydrophobic part and a hydrophilic part. The fatty acid tails repel water, while the phosphate-containing head attracts water. In water, the heads face outward toward the solution and the tails gather in the middle of the bilayer.

Fatty acids can be saturated or unsaturated. Saturated fatty acids have only single bonds between carbon atoms. Stearic acid is one example. Unsaturated fatty acids contain one or more double bonds. Oleic acid is an example, and most unsaturated fats are liquid at room temperature and are called oils. Monounsaturated fats, such as olive oil, have one double bond. Polyunsaturated fats, such as canola oil, have more than one. Straight saturated fatty acids pack tightly, so they are usually solid at room temperature. Animal fats with stearic acid and palmitic acid, as well as butter with butyric acid, are examples.

Unsaturated fatty acids can also be cis or trans. These terms describe the arrangement around a double bond. In cis fats, the hydrogens are on the same plane. In trans fats, they are on different planes. The cis double bond creates a kink that prevents tight packing, which helps keep the fat liquid. Olive oil, corn oil, canola oil, and cod liver oil are examples of unsaturated fats. Unsaturated fats tend to lower blood cholesterol levels, while saturated fats can contribute to plaque formation in arteries.

Trans fats are often made by hydrogenating oils to make them more semi-solid for processed foods. During this process, some cis double bonds can change to trans double bonds. Margarine, some peanut butter, and shortening are examples of artificially hydrogenated trans fats. Studies show that more trans fats in the diet can raise low-density lipoproteins, or LDL, the “bad” cholesterol. This can increase plaque buildup in arteries and raise the risk of heart disease.

Omega-3 fatty acids are essential fatty acids, which means the body needs them but does not make them. They must come from the diet. Omega-3s are one of only two known essential fatty acid groups for humans, along with omega-6 fatty acids. They are polyunsaturated, and the name omega-3 means the third carbon from the end is part of a double bond. Alpha-linolenic acid is an example. It has three cis double bonds and a curved shape. Salmon, trout, and tuna are good sources. Research suggests omega-3 fatty acids can reduce the risk of sudden death from heart attacks, lower blood triglycerides, decrease blood pressure, prevent blood clotting, and reduce inflammation. They may also help lower the risk of some cancers in animals.

Lipids, Fats, and Cell Membranes

functional groups

Functional Groups in Organic Chemistry

Functional groups in organic chemistry are groups of atoms that give molecules specific properties. When these groups attach to a carbon skeleton, they can change how the molecule behaves. Some functional groups make a molecule hydrophilic, or water-attracting. Others make it hydrophobic, or water-repelling. Functional groups are a key part of organic chemistry and are also found in major biological molecules. They appear in carbohydrates, proteins, lipids, and nucleic acids. Each functional...

structure of lipids

Lipids are nonpolar molecules that do not mix well with water. They are hydrophobic, which means “water fearing,” because they contain mostly nonpolar carbon-carbon and carbon-hydrogen bonds. In cells, lipids store long-term energy as fats, help insulate plants and animals, and form protective water-repellent layers on feathers and fur. They are also part of cell membranes and serve as building blocks for many hormones. Common lipids include fats, oils, waxes, phospholipids, and steroids. A...

chemistry of the cell

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chemistry of carbohydrates

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amino acids

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peptide bonds

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nucleic acids

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dna replication

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key terms and concepts

Explore how lipids store energy, build cell membranes, and differ as saturated, unsaturated, trans, and omega-3 fats in high school biology.

Lipids, Fats, and Cell Membranes | JoVE K12

chemistry

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New York State Science Learning Standards

matter-and-energy-in-organisms-and-ecosystems

Matter and Energy in Organisms and Ecosystems

HS-LS1-6.

Characteristics of Life

Biology is a natural science that studies life and living organisms, including their structure, function, development, interactions, evolution, ...

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Cell Structure

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

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

Visualizing Onion and Human Cells
ExpandIn this experiment you will prepare different types of cells from a plant and animal, onion and human ...

What are Cells?

Cell Diversity

The concept of a cell started with microscopic observations of dead cork tissue by Robert Hooke in 1665. Hooke coined the term &#34;cell&#34; based on the ...

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 ...

The Central Dogma

The DNA Helix

Nucleic Acids

DNA as a Genetic Template

Structure of a Gene

A gene is the fundamental unit of heredity. Every individual has two copies of each gene, one inherited from each parent. Although most people contain the ...

Chromosome Structure

Base-pairing and DNA Repair

What is Gene Expression?

A gene is a stretch of DNA that serves as the blueprint for functional RNAs and proteins. Since DNA is comprised&#160; of nucleotides and proteins are ...

RNA Structure

The basic structure of RNA consists of a string of ribonucleotides attached by phosphodiester bonds. Although most RNA is single-stranded, it can form ...

Protein Families

Types of RNA

Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse ...

Conservation of Protein Domains

Transcription

Transcription is the synthesis of RNA from a DNA sequence by RNA polymerase. It is the first step in producing a protein from a gene sequence. ...

Globular and Fibrous Proteins

Translation

Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes ...

Intrinsically Disordered Proteins

Ribosomes

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

Protein Complex Assembly

Protein and Protein Structures

Conjugated Proteins

Proteins: From Genes to Degradation

Amyloid Fibrils

What are Proteins?

Proteins are polymers of amino acids linked together by peptide bonds. Proteins and polypeptides are interchangeably used to refer to long chains of amino ...

Ligand Binding Sites

Protein Organization

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Protein-Protein Interfaces

Protein Folding

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Conserved Binding Sites

Cofactors and Coenzymes

Enzymes are proteins made of amino acids. The functional group of each constituent amino acid catalyzes a wide variety of chemical reactions via ionic ...

Cooperative Allosteric Transitions

Protein Kinases and Phosphatases

GTPases and their Regulation

Covalently Linked Protein Regulators

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Protein Complexes with Interchangeable Parts

Mechanical Protein Function

Structural Protein Function

Protein Networks

Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells. [Assessment Boundary: Assessment does not include identification of specific cell or tissue types, whole body systems, specific protein structures and functions, or the biochemistry of protein synthesis.]

HS-LS1-1

Levels of Organization

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Animal and Plant Cell Structure

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Structural Organization of the Human Body: An Overview

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Overview of Human Digestion

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Anatomy of the Intestines

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Accessory Organs

Accessory organs are those that participate in the digestion of food but do not come into direct contact with it like the mouth, stomach, or intestine do. ...

Lipid Digestion

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Protein Digestion

Protein digestion begins in the stomach, where the highly acidic environment can easily disrupt protein structure by exposing the peptide bonds of ...

Carbohydrate Digestion

Carbohydrate digestion and metabolism break down simple and complex carbohydrates from food into saccharides (i.e., sugars) for the body to use as energy. ...

What is a Nervous System?

Overview

The nervous system is the collection of specialized cells responsible for maintaining an organism&rsquo;s internal environment and coordinating ...

The Parasympathetic Nervous System

Overview

The parasympathetic nervous system is one of the two major divisions of the autonomic nervous system. This parasympathetic system is responsible ...

The Sympathetic Nervous System

Overview

The sympathetic nervous system&mdash;one of the two major divisions of the autonomic nervous system&mdash;is activated in times of stress. It ...

Oogenesis

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What is a Sensory System?

Sensory systems detect stimuli&mdash;such as light and sound waves&mdash;and transduce them into neural signals that can be interpreted by the nervous ...

Fertilization

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What is the Skeletal System?

Overview

The adult human skeleton comprises 206 bones that are connected through cartilage, tendons, and ligaments. The skeleton provides a rigid ...

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An Introduction to the Zebrafish: Danio rerio

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Physiology of the Circulatory System

Homeostasis
Conditions in the external environment of an organism can change rapidly and drastically. To survive, organisms must maintain a fairly ...

Anatomy of the Circulatory System

The human circulatory system consists of blood, blood vessels that carry blood away from the heart, around the body, and back to the heart, and the heart ...

Measuring Blood Pressure
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Anatomy of the Heart

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Measuring Circulatory System Function in Humans
ExpandBefore starting the experiment go to the front of the room and collect an alcohol swab, a ...

Blood Flow

Blood is pumped by the heart into the aorta, the largest artery in the body, and then into increasingly smaller arteries, arterioles, and capillaries. The ...

What Are Osmoregulation and Excretion?

Organisms must keep bodily fluids at a constant temperature and pH while maintaining specific solute concentrations in order to support life functions. ...

Blood Withdrawal I

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN
Blood collection is a common requirement for ...

Kidney Structure

The kidneys are two large bean-shaped organs located in the upper abdomen. They filter the blood several times a day to remove toxins and rebalance water ...

Blood Withdrawal II

Source: Kay Stewart, RVT, RLATG, CMAR; Valerie A. Schroeder, RVT, RLATG. University of Notre Dame, IN
The collection of blood from mice and rats for ...

What is the Immune System?

Overview

The immune system comprises diverse biological structures and processes that protect the body from disease. These processes can be classified ...

Bone Remodeling

Bone remodeling is a continuous and balanced process of bone resorption by osteoclasts and bone formation by osteoblasts. In adults, it helps maintain ...

Spermatogenesis

Spermatogenesis is the process by which haploid sperm cells are produced in the male testes. It starts with stem cells located close to the outer rim of ...

Bone Structure

Within the skeletal system, the structure of a bone, or osseous tissue, can be exemplified in a long bone, like the femur, where there are two types of ...

Breathing

The process of breathing, inhaling and exhaling, involves the coordinated movement of the chest wall, the lungs, and the muscles that move them. Two ...

Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. [Clarification Statement: Emphasis is on functions at the organism system level such as nutrient uptake, water delivery, and organism movement in response to neural stimuli. An example of an interacting system could be an artery depending on the proper function of elastic tissue and smooth muscle to regulate and deliver the proper amount of blood within the circulatory system.] [Assessment Boundary: Assessment does not include interactions and functions at the molecular or chemical reaction level.]

HS-LS1-2

What is Homeostasis?

Maintaining homeostasis requires that the body continuously maintain its internal conditions. Each physiological condition has a particular set point, ...

Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis. [Clarification Statement: Examples of investigations could include heart rate response to exercise, stomate response to moisture and temperature, and root development in response to water levels.] [Assessment Boundary: Assessment does not include the cellular processes involved in the feedback mechanism.]

HS-LS1-3

Lipids, Fats, and Cell Membranes

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