Name: antibiotic resistance in cloning
Uploaded: 2026-08-26T08:20:54.022Z
Duration: 1 min 45 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Life Sciences

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

From Molecules To Organisms: Structures And Processes

HS-LS1-8

Antibiotic Selection

A sele&#xE7;&#xE3;o de antibi&#xF3;tico &#xE9; usada geralmente para garantir que uma col&#xF4;nia bacteriana contenha um plasm&#xED;deo com algumas caracter&#xED;sticas chave. 
Um gene resistente ao antibi&#xF3;tico, e um gene de interesse que um pesquisador quer expressar. 
Para que as bact&#xE9;rias absorvam o plasm&#xED;deo, ambos precisam ser incubados juntos, e passar por um choque de calor para promover a incorpora&#xE7;&#xE3;o. 
Nem toda bact&#xE9;ria absorver&#xE1; uma c&#xF3;pia do plasm&#xED;deo. 
Como o objetivo &#xE9; isolar bact&#xE9;rias que possuem uma c&#xF3;pia, os pesquisadores adicionam um pouco da cultura bacteriana em uma placa contendo um antibi&#xF3;tico. 
Apenas as bact&#xE9;rias que tiverem o plasm&#xED;deo que cont&#xE9;m o gene de resist&#xEA;ncia ser&#xE3;o capazes de degradar o antibi&#xF3;tico e crescer na placa. 
Durante os dias seguintes, uma &#xFA;nica bact&#xE9;ria formar&#xE1; col&#xF4;nias que poder&#xE3;o ser selecionadas para trabalho adicional.

Courvalin, P. 2016. "Por que a resistência aos antibióticos é uma doença emergente mortal?" Microbiologia Clínica e Infecção 22 (5): 405–7. [<a href="https://doi.org/10.1016/j.cmi.2016.01.012" target="__blank">Fonte</a>]

Daubin, Vincent e Gergely J. Szöllősi. 2016. "Transferência horizontal de genes e a história da vida." Perspectivas de Cold Spring Harbor em Biologia 8 (4). [<a href="https://doi.org/10.1101/cshperspect.a018036" target="__blank">Fonte</a>]

Hiltunen, Teppo, Marko Virta e Anna-Liisa Laine. 2017. "Resistência a antibióticos na natureza: uma perspectiva ecoevolutiva." Transações Filosóficas da Royal Society B: Ciências Biológicas 372 (1712). [<a href="https://doi.org/10.1098/rstb.2016.0039" target="__blank">Fonte</a>]

seleção de antibióticos

<h4>Vis&#xE3;o Geral</h4>
 
 Investigadores usam genes de resist&#xEA;ncia a antibi&#xF3;ticos para identificar bact&#xE9;rias que possuem um plasm&#xED;deo contendo o seu gene de interesse. A resist&#xEA;ncia a antibi&#xF3;ticos ocorre naturalmente quando uma muta&#xE7;&#xE3;o espont&#xE2;nea do DNA cria altera&#xE7;&#xF5;es em genes bacterianos que eliminam a atividade dos antibi&#xF3;ticos. As bact&#xE9;rias podem compartilhar esses novos genes de resist&#xEA;ncia com os seus descendentes e outras bact&#xE9;rias. O uso excessivo e o uso indevido de antibi&#xF3;ticos criaram uma crise de sa&#xFA;de p&#xFA;blica, &#xE0; medida que bact&#xE9;rias resistentes e multi-resistentes continuam a desenvolver-se.
 
 <h4>A Resist&#xEA;ncia a Antibi&#xF3;ticos &#xE9; uma Ferramenta Essencial na Engenharia Gen&#xE9;tica</h4>
 
 Antibi&#xF3;ticos, como a penicilina, s&#xE3;o f&#xE1;rmacos que matam ou param o crescimento bacteriano. Bact&#xE9;rias que naturalmente ou artificialmente adquiriram genes de resist&#xEA;ncia a antibi&#xF3;ticos n&#xE3;o respondem a antibi&#xF3;ticos. Os cientistas exploram isso criando plasm&#xED;deos&#x2014;pequenos peda&#xE7;os auto-replicantes de DNA&#x2014;que carregam um gene de resist&#xEA;ncia a antibi&#xF3;ticos e um gene de interesse. A resist&#xEA;ncia a antibi&#xF3;ticos &#xE9; parte integrante da clonagem do DNA que permite ao investigador identificar c&#xE9;lulas que incorporaram um DNA de interesse.
 
 O DNA de interesse do investigador &#xE9; introduzido em c&#xE9;lulas bacterianas usando um processo chamado transforma&#xE7;&#xE3;o. A transforma&#xE7;&#xE3;o bacteriana envolve a cria&#xE7;&#xE3;o tempor&#xE1;ria de pequenos buracos na parede celular bacteriana para permitir a incorpora&#xE7;&#xE3;o de DNA externo, como um plasm&#xED;deo. S&#xF3; algumas c&#xE9;lulas bacterianas incorporam novo DNA. Uma vez que o plasm&#xED;deo inclui tanto o DNA de interesse como um gene que confere resist&#xEA;ncia a um antibi&#xF3;tico espec&#xED;fico, aplicar o antibi&#xF3;tico &#xE0;s c&#xE9;lulas bacterianas (ou seja, sele&#xE7;&#xE3;o por antibi&#xF3;ticos) pode ajudar a determinar que c&#xE9;lulas foram geneticamente modificadas.
 
 O investigador espalha as c&#xE9;lulas bacterianas em uma placa de cultura contendo um antibi&#xF3;tico escolhido. Apenas bact&#xE9;rias contendo o gene de resist&#xEA;ncia ao antibi&#xF3;tico sobrevivem e crescem na placa. Ap&#xF3;s alguns dias, o investigador pode selecionar uma col&#xF3;nia bacteriana para cultivar para outras experi&#xEA;ncias&#x2014;como estudos de express&#xE3;o gen&#xE9;tica. Ap&#xF3;s a sele&#xE7;&#xE3;o por antibi&#xF3;tico, o investigador testa ainda mais as bact&#xE9;rias usando outros m&#xE9;todos (por exemplo, PCR) para confirmar que o DNA de interesse est&#xE1; correto. Erros muitas vezes ocorrem, como o plasm&#xED;deo n&#xE3;o conter o gene de interesse de todo.
 
 <h4>As Bact&#xE9;rias Podem Adquirir Resist&#xEA;ncia a Antibi&#xF3;ticos Naturalmente</h4>
 
 As bact&#xE9;rias podem adquirir resist&#xEA;ncia a antibi&#xF3;ticos atrav&#xE9;s de muta&#xE7;&#xF5;es espont&#xE2;neas do DNA que alteram as prote&#xED;nas produzidas pela c&#xE9;lula. Bact&#xE9;rias resistentes podem produzir prote&#xED;nas que fazem com que o antibi&#xF3;tico seja degradado, bombeado para fora da c&#xE9;lula ou impedido de interagir com o seu alvo. Por exemplo, o antibi&#xF3;tico vancomicina inibe a s&#xED;ntese da parede celular bacteriana. Algumas bact&#xE9;rias desenvolveram resist&#xEA;ncia a este antibi&#xF3;tico alterando os tipos de subunidades proteicas&#x2014;amino&#xE1;cidos&#x2014;usados na cria&#xE7;&#xE3;o da sua parede celular para outros que n&#xE3;o s&#xE3;o afetados pela vancomicina.
 
 Assim que os genes de resist&#xEA;ncia a antibi&#xF3;ticos emergem, as bact&#xE9;rias podem pass&#xE1;-los para os seus descendentes. As bact&#xE9;rias tamb&#xE9;m podem adquirir genes de resist&#xEA;ncia a antibi&#xF3;ticos de outras bact&#xE9;rias da mesma ou de diferentes esp&#xE9;cies atrav&#xE9;s de um processo chamado transfer&#xEA;ncia gen&#xE9;tica horizontal (HGT). Existem tr&#xEA;s mecanismos de HGT: transforma&#xE7;&#xE3;o, conjuga&#xE7;&#xE3;o e transdu&#xE7;&#xE3;o. Genes de resist&#xEA;ncia a antibi&#xF3;ticos s&#xE3;o frequentemente encontrados em plasm&#xED;deos ou transpos&#xF5;es&#x2014;peda&#xE7;os de DNA que s&#xE3;o facilmente transferidos entre bact&#xE9;rias&#x2014;que s&#xE3;o trocados durante a HGT. Como resultado, novos tipos de resist&#xEA;ncia a antibi&#xF3;ticos podem espalhar-se rapidamente para v&#xE1;rios tipos de bact&#xE9;rias infecciosas.
 
 <h4>O Uso Cl&#xED;nico Excessivo e Indevido de Antibi&#xF3;ticos Produz &#x201C;Superbact&#xE9;rias&#x201D;</h4>
 
 Os antibi&#xF3;ticos s&#xE3;o um tratamento cr&#xED;tico para infec&#xE7;&#xF5;es bacterianas. No entanto, o seu uso pode fazer com que as bact&#xE9;rias se tornem resistentes e tornem o antibi&#xF3;tico ineficaz, levando a infec&#xE7;&#xF5;es intrat&#xE1;veis e potencialmente mortais. O uso excessivo e o uso indevido de antibi&#xF3;ticos&#x2014;por exemplo, o uso de antibi&#xF3;ticos para tratar infec&#xE7;&#xF5;es virais (em vez de bacterianas) ou para aumentar o crescimento pecu&#xE1;rio&#x2014;&#xE9; problem&#xE1;tico porque promove resist&#xEA;ncia.
 
 Os antibi&#xF3;ticos fazem com que a resist&#xEA;ncia evolua porque matam bact&#xE9;rias suscet&#xED;veis e deixam apenas os indiv&#xED;duos resistentes. As bact&#xE9;rias sobreviventes dividem-se rapidamente, produzindo descendentes com a mesma resist&#xEA;ncia a antibi&#xF3;ticos. Quando os antibi&#xF3;ticos s&#xE3;o muito usados, essa press&#xE3;o de sele&#xE7;&#xE3;o faz com que o n&#xFA;mero de bact&#xE9;rias resistentes na popula&#xE7;&#xE3;o aumente rapidamente. Esta &#xE9; uma grande preocupa&#xE7;&#xE3;o de sa&#xFA;de p&#xFA;blica porque aumenta a resist&#xEA;ncia a antibi&#xF3;ticos e cria &#x201C;superbact&#xE9;rias&#x201D; que s&#xE3;o resistentes a m&#xFA;ltiplos antibi&#xF3;ticos. O uso excessivo cont&#xED;nuo e o uso indevido de antibi&#xF3;ticos podem eventualmente esgotar as op&#xE7;&#xF5;es de tratamento para infec&#xE7;&#xF5;es bacterianas.

Seleção de Antibióticos

Overview

Researchers use antibiotic resistance genes to identify bacteria that possess a plasmid containing their gene of interest. Antibiotic resistance ...

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Education

JoVE Core

Biology

Biologia

Genetics

Genética

Biotechnology

Biotecnologia

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

antibiotic resistance in cloning

Antibiotic resistance genes help scientists find bacteria that took up a plasmid with a gene of interest. In genetic engineering, this resistance is used as a marker, not just as a medical concern. The same process also connects to the growing problem of resistant bacteria in the real world.

Antibiotics, such as penicillin, stop bacterial growth or kill bacteria. When bacteria naturally have, or are engineered to carry, an antibiotic resistance gene, the antibiotic no longer works on them. Researchers build plasmids, which are small pieces of self-replicating DNA, with both the gene of interest and a resistance gene. This makes antibiotic resistance an important part of DNA cloning and cell selection.

To move DNA into bacteria, scientists use transformation. During transformation, small holes are made in the bacterial cell wall so external DNA, like a plasmid, can enter. Only some cells take up the new DNA. Scientists then place the bacteria on a plate containing the chosen antibiotic. Only cells with the resistance gene survive and form colonies.

After a few days, a colony can be picked and grown for later experiments, such as gene expression studies. The bacteria are often tested again with methods like PCR to confirm that the DNA of interest is correct. This step matters because mistakes can happen, including plasmids that do not contain the target gene at all.

Bacteria can also gain antibiotic resistance naturally through spontaneous DNA mutations. These changes may produce proteins that break down the antibiotic, pump it out of the cell, or block it from reaching its target. For example, vancomycin blocks bacterial cell wall synthesis, but some bacteria avoid its effect by changing the amino acid subunits used to build their cell wall.

Once resistance genes appear, bacteria can pass them to offspring. They can also share them with other bacteria through horizontal gene transfer, or HGT. The three main HGT methods are transformation, conjugation, and transduction. Resistance genes are often carried on plasmids or transposons, which can move easily between cells and spread new resistance traits quickly.

Antibiotic overuse and misuse have made this problem worse. Using antibiotics for viral infections or to increase livestock growth can select for resistant bacteria. The susceptible bacteria die, while resistant survivors keep dividing and passing on the same trait. Over time, this can lead to multi-resistant bacteria, or superbugs, and may leave fewer treatment options for bacterial infections.

Antibiotic Resistance in Cloning

what is genetic engineering?

How Scientists Edit DNA for New Traits

Genetic engineering changes an organism’s DNA to add useful traits. Scientists use it in bacteria, plants, animals, and even viruses for research, medicine, agriculture, and industry. It can bring major benefits, but it also raises ethical concerns about humans and the food supply. This work is possible because DNA has the same basic structure and genetic code across life. That shared code lets scientists modify DNA in several ways. One method is CRISPR/Cas9, often called molecular scissors,...

dna isolation

Steps in DNA Extraction

DNA extraction is the process of removing and purifying DNA from cells. It is used in many biotechnology and research applications, including molecular cloning. The main goal is to free DNA from the cell and prepare it for later study or use. The first step is cell lysis, which means breaking cells open. Researchers may use a homogenizer, sonicator, or bead beater to physically lyse the cells. They also often add detergent to chemically disrupt the lipid-based cell membranes. This helps...

recombinant dna technology

Recombinant DNA in Cloning and GMOs

Recombinant DNA is made by joining DNA from different sources in the lab. Scientists often use it to clone genes and study them in cells that are easy to handle, such as bacteria. Organisms that carry recombinant DNA are called genetically modified organisms, or GMOs. This technology gives scientists new tools for research, medicine, and agriculture. To build recombinant DNA, researchers place a gene of interest into a vector, which is a DNA carrier that moves foreign DNA into a host cell. The...

PCR Cycle for DNA Amplification

PCR is a laboratory method for making many copies of a DNA segment. It can turn a small amount of DNA into millions or even billions of copies in just a few hours. The process uses a heat-resistant DNA polymerase inside a machine called a thermocycler. PCR was developed by Kary Mullis in 1983, and he received the 1993 Nobel Prize in Chemistry for it. The method is fast, relatively inexpensive, and precise. It has become useful for molecular cloning, gene mutagenesis, pathogen detection, gene...

complementary dna

From mRNA to cDNA for Gene Studies

Complementary DNA, or cDNA, is made from messenger RNA (mRNA) so scientists can study which genes are active in cells and tissues. Only genes that are transcribed into mRNA are expressed. By extracting mRNA from cells, researchers can compare gene expression across samples. cDNA is produced by reverse transcription. This process copies mRNA into DNA, which is useful because mRNA does not contain introns, or non-coding regions, and other regulatory sequences. As a result, cDNA can help...

antibiotic selection

Antibiotic resistance genes help scientists find bacteria that took up a plasmid with a gene of interest. In genetic engineering, this resistance is used as a marker, not just as a medical concern. The same process also connects to the growing problem of resistant bacteria in the real world. Antibiotics, such as penicillin, stop bacterial growth or kill bacteria. When bacteria naturally have, or are engineered to carry, an antibiotic resistance gene, the antibiotic no longer works on them.

transgenic organisms

Creating Transgenic Plants and Animals

Transgenic organisms are genetically engineered to carry a transgene, which is a gene from a different species, in their genome. The inserted gene may be a new gene for that organism or a different version of one it already has. Scientists usually make transgenes with recombinant DNA and DNA cloning methods. Researchers use transgenic bacteria, plants, and animals to answer biological questions and to build useful tools. To make a transgenic organism, they first choose a transgenesis method,...

in-vitro mutagenesis (gene knockouts)

Knockout Mice and Gene Replacement

Knockout mice help researchers study gene function by showing what happens when a gene is turned off. These engineered animals are also useful for modeling human diseases such as cancer, Parkinson’s disease, and diabetes. A specific gene can be targeted by using a targeting vector, which is a piece of engineered DNA that replaces the normal gene and inactivates it. The vector has matching DNA sequences on both ends. These homologous sequences let the vector swap in for the target gene through...

crispr

CRISPR-Cas9 Gene Editing in Action

CRISPR-Cas9 is a genome editing tool that lets scientists change DNA at a specific location. It can add, remove, or rearrange genetic material. Researchers study it because it may help treat genetic disorders such as hemophilia and sickle cell anemia. CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats, and Cas9 is a CRISPR-associated protein 9. The basic system includes a Cas9 endonuclease, which is an enzyme that cuts DNA, and a small RNA that guides Cas9 to the...

gene therapy

Gene Delivery for Serious Diseases

Gene therapy is a technique used to treat serious disease by adding a gene to a person’s cells. The added gene may be a healthy copy of a mutated gene. It may also be a different gene that inactivates or compensates for the disease-causing gene. One example is severe combined immunodeficiency, or SCID, caused by a mutation in the gene for adenosine deaminase. In that case, a working copy of the gene can be inserted so the patient’s cells make the enzyme again. This can cure the disease in some...

embryonic stem cells

How Embryonic Stem Cells Become Specialized

Embryonic stem cells are pluripotent cells that have not yet specialized. Pluripotent means they can give rise to many different cell types in the body. Because of this, they are useful in science and medicine for making cells needed in research or for replacing cells lost to damage or disease. These cells come from the inner cell mass of a blastocyst, which is an early embryo about 3 to 5 days after fertilization in humans. At this stage, the embryo has not yet implanted in the uterus. Human...

adult stem cells

Adult Stem Cells in the Small Intestine

Adult stem cells help maintain tissues by replacing old or damaged cells. These undifferentiated cells divide to make more stem cells or progenitor cells, which then become mature, specialized cells. Small groups of adult stem cells are found in many tissues, including the bone marrow, brain, skin, and gut. The small intestine shows this process clearly. Its lining, called the epithelium, is renewed continuously by adult stem cells. It is also the fastest replaced tissue in the human body,...

induced pluripotent stem cells

Reprogramming Mature Cells into Stem Cells

Reprogramming mature cells into stem cells lets scientists turn specialized cells back into an unspecialized state. These cells are called induced pluripotent stem cells, or iPSCs. Like embryonic stem cells, iPSCs are pluripotent, which means they can form all cell types. To make iPSCs, researchers start with mature cells such as skin fibroblasts or blood cells. The cells are grown in culture, and genes for several transcription factors are delivered with a viral vector. The cells then make...

reproductive cloning

Cloning Animals with SCNT

Reproductive cloning can produce a genetically identical copy of an entire organism. In adult animals, this is usually done with somatic cell nuclear transfer, or SCNT. Another way clones can form is by splitting an early embryo, which is similar to how identical twins arise naturally. In SCNT, an egg cell is taken from an animal and its nucleus is removed. This creates an enucleated egg. A somatic cell, which is any body cell that is not a sex cell, is then taken from the animal to be cloned.

genomics

Genomics and DNA Sequencing

Genomics studies the full set of genetic material in an organism. In humans, that genome includes the DNA carried in 23 pairs of chromosomes in the nucleus, along with mitochondrial DNA. Genomics looks at both coding DNA and non-coding DNA, which helps scientists study how living things are built and how they differ. This field is useful in many areas of biology and medicine. Scientists use genomics to build phylogenetic trees, improve crop productivity and sustainability, help with criminal...

key terms and concepts

Learn how antibiotic resistance genes help scientists select transformed bacteria, and why resistance and superbugs are a major health concern.

Antibiotic Resistance in Cloning | JoVE K12

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A coleção JoVE Core dá vida à biologia através de mais de 300 vídeos de animação concisos e fáceis de entender que explicam conceitos-chave de biologia, além de mais de 150 vídeos de Cientistas em ação que mostram experimentos reais em pesquisa realizados nos laboratórios atualmente.

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SB6.e

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 ...

DNA Base Pairing

Erwin Chargaff&#x2019;s rules on DNA equivalence paved the way for the discovery of base pairing in DNA. Chargaff&#x2019;s rules state that in a ...

From DNA to Protein

The flow of genetic information in cells from DNA to mRNA to protein is described by the central dogma, which states that genes specify the sequence of ...

The DNA Helix

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most viruses. DNA ...

The Central Dogma

The central dogma explains the flow of genetic information from DNA nucleotides to the amino acid sequence of proteins.
RNA is the Missing Link Between ...

Genomic DNA in Prokaryotes

The genome of most prokaryotic organisms consists of double-stranded DNA organized into one circular chromosome in a region of cytoplasm called the ...

Genomic DNA in Eukaryotes

Eukaryotes have large genomes compared to prokaryotes. To fit their genomes into a cell, eukaryotic DNA is packaged extraordinarily tightly inside the ...

Overview

Deoxyribonucleic acid, or DNA, is the genetic material responsible for passing traits from generation to generation in all organisms and most ...

DNA Packaging

Overview

Eukaryotes have large genomes compared to prokaryotes. In order to fit their genomes into a cell, eukaryotes must pack their DNA tightly inside ...

RNA Structure

Overview
The basic structure of RNA consists of a five-carbon sugar and one of four nitrogenous bases. Although most RNA is single-stranded, it can form ...

RNA Stability

Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations ...

pre-mRNA Processing

In eukaryotic cells, transcripts made by RNA polymerase are modified and processed before exiting the nucleus. Unprocessed RNA is called precursor mRNA or ...

Types of RNA

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

DNA as a Genetic Template

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 ...

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. ...

Translation

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

Ribosomes

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

tRNA Activation

Initiation of Translation

Termination of Translation

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 ...

Cells of the Epidermis

The epidermis is made of four or five layers of epithelial cells, depending on its location in the body. From deep to superficial, these layers are the ...

Bone Cells and Tissue

Bones contain a relatively small number of cells entrenched in a matrix of organic and inorganic components. Although bone cells compose only a small ...

Gross Anatomy of Skeletal Muscles

The connective tissues play a significant role in arranging the muscle fibers into a hierarchical structure that forms a complete muscle. Consider a ...

Structure of Cardiac Muscles

Cardiac muscle, or myocardium, is a specialized type of muscle found exclusively in the heart. Its unique structural and functional characteristics enable ...

structure-and-organization-of-smooth-muscles

Structure and Organization of Smooth Muscles

In the human body, smooth muscle tissue is found lining the visceral and tubular organs such as the liver, lungs, blood vessels, and respiratory tract.
...

Chromosome Replication

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Neurons: The Cell Body and the Dendrites

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Lampbrush Chromosomes

In 1882, Flemming observed lampbrush chromosomes (LBC) in salamander eggs. Later in 1892, R&#252;ckert observed LBCs in shark egg cells and coined the ...

Neurons: The Axon

The axon is a long, thin extended portion of the neuron that carries impulses from its cell body toward the effector cell.
Axoplasm, the axon&#39;s ...

Polytene Chromosomes

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Nervous Tissue: Neuron Types

Neurons, the fundamental units of the nervous system, can be classified based on both their structural and functional characteristics.
Structurally, ...

Euchromatin

The extent of chromatin compaction can be studied by staining chromatin using specific DNA binding dyes. Under the microscope, the dense-compacted regions ...

Nervous Tissue: Glial Cells

Glial cells or neuroglia are non-neuronal cells in the nervous system that outnumber neurons. These include astrocytes, oligodendrocytes, microglia, and ...

Heterochromatin

Lymphoid Cells and Tissues

Lymphoid cells and lymphoid tissues are the two major components of lymphoid organs.
Lymphoid cells consist of immune system cells such as B and T ...

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Chromatin Position Affects Gene Expression

Chromatin is the massive complex of DNA and proteins packaged inside the nucleus. The complexity of chromatin folding and how it is packaged inside the ...

Two structural features of the DNA molecule provide a basis for the mechanisms of heredity: the four nucleotide bases and its double-stranded nature. The ...

Organization of Genes

Chromosome Structure

A functional eukaryotic chromosome must contain three elements: a centromere, telomeres, and numerous origins of replication.
The centromere is a DNA ...

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. Emphasis is on the conceptual understanding that DNA sequences determine the amino acid sequence and thus protein structure. Students can produce scientific writing, or presentations, and/or physical models that communicate constructed explanations.

HS-LS1-1

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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Levels of Organization

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The Scientific Method

The scientific method is a detailed, empirical problem-solving process used by biologists and other scientists. This iterative approach involves ...

Taxonomy

Taxonomy is the science of defining and naming groups of biological organisms based on shared characteristics. It uses a hierarchy of increasingly ...

Phylogeny

Phylogeny is concerned with the evolutionary diversification of organisms or groups of organisms. A group of organisms with a name is called a taxon ...

Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms. Emphasis is on functions at the organism system level such as nutrient uptake, water delivery, or 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.

HS-LS1-2

Overview of Metabolism

Living cells constantly carry out various chemical reactions which are necessary for their proper functioning. These reactions are interlinked to one ...

Regulation of Metabolism

Cellular needs and conditions vary from cell to cell and change within individual cells over time. For example, the required enzymes and energetic demands ...

Positive and Negative Feedback Loops

Animal organs and organ systems constantly adjust to internal and external changes through a process called homeostasis (&#34;steady state&#34;). Examples ...

Functions of Life

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Requirements for Human Life

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What is Homeostasis?

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

Negative and Positive Feedback

Homeostatic Imbalance

Homeostasis is the maintenance of a stable internal environment within the body, which is crucial for the proper functioning of cells, tissues, organs, ...

pH Homeostasis

Acid-base homeostasis is essential for maintaining normal physiological activities in humans. The pH of various body fluids is strictly regulated because ...

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Homeostatic Imbalances in Body Temperature

Hyperthermia is an umbrella term for elevated body temperature that occurs when heat production exceeds the body&#39;s ability to dissipate it.
...

Regulation of Food Intake

The hypothalamus releases peptides influencing feeding behavior.
Two hypothalamic neuronal groups participate in this process.
Neuropeptide Y (NPY) and ...

Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis in living organisms. Examples of investigations could include heart rate responses to exercise, stomate responses to moisture and temperature, root development in response to water levels, or cell response to hypertonic and hypotonic environments.

HS-LS1-3

What is the Cell Cycle?

The cell cycle refers to the sequence of events occurring throughout a typical cell&#8217;s life. In eukaryotic cells, the somatic cell cycle has two ...

Interphase

The cell cycle occurs over approximately 24 hours (in a typical human cell) and in two distinct stages: interphase, which includes three phases of the ...

Use a model to illustrate the role of the cell cycle and differentiation in producing and maintaining complex organisms. Emphasis is on conceptual understanding that mitosis passes on genetically identical materials via replication, not on the details of each phase in mitosis.

HS-LS1-4

Antibiotic Resistance in Cloning

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