Deoxyribonucleic acid is a molecule composed of two polynucleotide chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses.
Deoxyribonucleic acid is a molecule composed of two polynucleotide chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses.
The presentation includes about the basic knowledge of Deoxyribonucleic Acid or DNA. It involves the definition, structure, occurence, quantity, chemical composition, stability, variety, types, molecular weight, complementary of base pairs, absorbance, viscosity, ionic interactions, alternative forms and functions of DNA.
bacteria reproduce by binary fission , which is a single cell, divides into two identical daughter cells. it occurs through formation of the Z ring that recruits additional proteins to form the septa ring.
The presentation includes about the basic knowledge of Deoxyribonucleic Acid or DNA. It involves the definition, structure, occurence, quantity, chemical composition, stability, variety, types, molecular weight, complementary of base pairs, absorbance, viscosity, ionic interactions, alternative forms and functions of DNA.
bacteria reproduce by binary fission , which is a single cell, divides into two identical daughter cells. it occurs through formation of the Z ring that recruits additional proteins to form the septa ring.
Cell DivisionCell Division in ProkaryotesBinary FissionDefMaximaSheffield592
Cell Division
Cell Division in Prokaryotes
Binary Fission
Definition
Bacterial cells divide by a method of asexual reproduction known as binary fission. Fission means splitting. So in the process the genetic material is replicated, the cell grows larger and then splits into two.
Genetic Material of the Bacterial Cell
The genetic information of a bacterial cell exists as a single, circular, double-stranded DNA molecule. Bacterial cells are prokaryotic cells; they lack a nucleus. The DNA of the bacterial cell is not surrounded by and enclosed within a nuclear membrane. It lies free within the protoplasm of the bacterial cell. Although the bacterial cell lacks a nucleus, the area of the cell protoplasm where the nucleus is found is called the nucleoid.
Prior to the Division of the Cell the DNA must be Doubled
Prior to the division of the bacterial cell, the DNA must be replicated, producing two copies that can be equally distributed to each of the two daughter cells. Replication of the DNA at a specific site on the DNA molecule called the origin of replication. The replication enzymes copy the DNA of both strands, moving around the circular DNA in both directions simultaneously until a specific site of termination is reached. When these enzymes have proceeded all the way around the circle of DNA, the cell possesses two copies of the genome. These “daughter” genomes are attached side-by-side to the plasma membrane.
Elongation of the Cell and Segregation of DNA to Opposite Ends of the Cell
As the DNA replicates, the cell elongates. The two circular molecules of DNA now separate and move apart toward opposite ends of the cell.
Fission of the Cell into two Daughter Cells
After the DNA molecules have been segregated to opposite ends of the cell, the bacterial cell will divide to form two daughter cells. Then a group of proteins that will operate together to separate the cell into two assemble at the site of separation. A key component of this group of division machinery proteins is the protein FtsZ. FtsZ proteins begin the separation process by forming a ring in the middle of the cell. Other components of the division apparatus then join the FtsZ ring, forming new plasma membrane that separates the cytoplasm into the two cells. This is followed by the formation of cell wall material in the separation zones. The result of the process of binary fission is two cells, each with its own circular, double stranded, DNA molecule.
The cell will now begin to split into two cells by a process called septation. This occurs as a septum forms in the middle of the cell. A protein called FtsZ forms a ring in the middle of the cell. As this process proceeds, the cell lays down new plasma membrane and cell wall materials in the zone between the attachment sites of the two daughter genomes. A new plasma membrane grows between the genomes; eventually, it reaches all the way into the center of the cell, dividing it in two. B ...
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Introduction to AI for Nonprofits with Tapp NetworkTechSoup
Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
Francesca Gottschalk - How can education support child empowerment.pptx
9.1 Cell Division
1. 9.1 Cell Division and Mitosis
1. Describe the organization of genetic material in a cell.
2. Describe the events that occur during the cell cycle including DNA replication and mitosis
Reading: 5: 109-130 (Reading Quiz due Monday before class)
The purpose of cell division:
Single-celled organisms like bacteria, yeast and some protists reproduce every time a cell divides. In
multicellular organisms cell divisions leads to an increase in size of the organism (growth) or can
replace dead or injured cells (repair).
When a eukaryotic cell, like this amoeba divides all the
organelles are partitioned between the two new cells
(mitochondria, chloroplasts, ribosomes, endoplasmic reticulum,
lysosomes Golgi etc).
Each new cell must also have a complete copy of the genetic
material (DNA).
http://www.microscopy-uk.org.uk/mag/artsep01/amoeba.html
Cell Division has three basic steps:
1. Duplication of the genetic material (DNA)
DNA is decondensed (big ball of string) while it is being copied. It only condenses into chromosomes after it
has been replicated.
2. Movement of the two copies of the DNA to opposite ends of the cell
This is the process of mitosis. Proteins called microtubules attach to chromosomes, pull them apart so that one
copy goes to each end of cell.
3. Cleavage of the cell into two daughter cells
This occurs after mitosis is complete. Cytokinesis = division of cytoplasm
Genome=Sum of all genetic material in a cell, all the DNA,
Our human genome consists of 3.2 Gigabases of DNA carried on 23 pairs of chromosomes
In Eukaryotes, The
DNA from one
chromosome is a very
very long linear
molecule Before cell
division the DNA is
coiled around histone
proteins which allow
it to become folded
up into a much more
compact structure
aka the
chromosome.
Before a cell can divide the DNA must be duplicated! Every chromosome must have two
sister chromatids.
2. 1. DNA Replication
DNA in cells is generally double-stranded
where two chains of nucleic acids are found
zippered together by hydrogen bonds. Each
differvfent nucleic acid is generally
represented by a letter A,C,G,T. There are
specific rules about how nucleic acids on
opposite strands pair. An A on one strand
pairs with a T on the other strand.
C pairs with G.
Being double stranded makes DNA very stable. It helps protect it from damage.
CSI can obtain DNA samples from hair brushes, dried spit, epithelial cells, etc. Even if the cells have died the
DNA is still intact. Intact DNA has been sequenced from some samples up to 100 000 years old….includes
ground sloths, mammoths, neanderthals (FYI: Reports of sequencing DNA from dinosaur fossils or insect
embedded in amber have not been able to be verified by repetition)
DNA replication is “semi-conservative” meaning that the parental strands separate and each one acts
as a template for a new strand. The origin of replication is a place where DNA replication begins
shown as bubbles where the strands open up.
There are many such places along each chromosome
QUESTION: Why is it more efficient to have many origins of
replication along one chromosome?
It’s faster to have multiple replication points than one replication
point.
It takes much less time if many spots are being operated upon.
Replication is directional 5’ 3’
All this means is that the DNA strands have two distinct ends a 5’ end and a 3’ end. When a new
strand is being made it is always made starting at its 5’ end and adding new nucleotides onto its 3’
end. AND it lines up antiparallel to the old strand.
3. QUESTION: If we condensed the DNA before it was replicated we
would have one chromatid we could represent like this
If your new strand was shown in red, after DNA replication is
complete what would the condensed chromosome look like. Where
would the red strands be? Using green and red pens draw your
chromosome with the two sister chromatids.
(Green on outside, green&red mess on the inside). After copying, each
chromatid is made of 1 new strand and 1 Old strand.
Once a chromosome has finished replicating its DNA each chromatid is made up of one new strand
and one old strand. This semi-conservative form of replication is beneficial so that in case a mistake
is made during replication, enzymes in the cell which check the DNA can tell which nucleotide letter is
correct and which one is wrong. Methyl groups are added to the old strand while in interphase.
CH3 CH3
| |
ACGGGCTCAC old strand (template)
TGTCCGAGTG new strand
↑
G and T do not pair. Question: Which one is wrong? (which one will the proof-reading
machinery fix?)
2. Mitosis (division of genetic material)
Cells spend only a very short time dividing. Most of the time cells have
their DNA decondensed inside the nucleus so it just looks like a big ball of
yarn. =INTERPHASE like on the left
QUESTION: When is DNA replicated –when DNA is condensed or
decondensed? WHY?
There are several steps to Mitosis:
1. DNA condenses into visible chromosomes and
the nuclear envelope breaks down.
2. All chromosomes line up at the centre of the
cell.
3. The chromosomes are pulled apart at their
centromeres (so that one chromatid goes to
1 one side of the cell and the other chromatid
3 goes to the other side.)* Both new cells must
have one copy of every chromosome
4. Once all the chromosomes reach opposite
ends of the cell then they decondense again
and the nuclear envelope reforms
2
4
4. This is how chromosomes line
up at the centre so that the
two chromatids go to opposite
sides of the cell.
Your turn:
Using the paper strips we will go through the process of mitosis with a cell that has three
chromosomes.
You should use this space afterwards to sketch out the basic process with a cell with 3 chromosomes.
3. Cytokinesis (division of cytoplasm)
Plant cells have rigid cell wall
Animal cells form a Instead they build a new cell
cleavage furrow wall between the daughter
proteins just under cells with materials brought
the plasma by vesicles from the Golgi.
membrane help pinch = cell plate while it is forming
it in two
CHROMOSOME NUMBER DOESN’T CHANGE IN MITOSIS
Before one of the lily cells divided it had 16 chromosomes. After it divided the two daughter cells
each had 16 chromosomes.
ONLY THE NUMBER OF CHROMATIDS ALTERNATES FROM 1 (after Mitosis)
2 (after DNA replication) 1 (after Mitosis) 2
Further Questions to consider:
5. 1. Give two reasons why DNA is not replicated during mitosis.
2. Below is a chromosome that has replicated its DNA. A few genes designated by letters are shown
on the chromatids. Draw a line through the chromosome to show what is the proper way to pull it
apart so that you get two identical chromosomes.
3. Here is part of a DNA strand of a chromosome in a cell in Interphase. In order for this cell to
divide it must copy the DNA. Label the 5’ and 3’ ends as appropriate. First sketch the strands
separating. Second, show the new strands halfway through copying and indicate which way
replication is occurring. Lastly, show the result after replication is complete.
4. Draw a cell with 4 chromosomes lined up at the centre of the cell. Be sure to draw the
chromosomes in proper orientation so that when the chromosomes pull apart one chromatid goes
to one end of the cell and the other chromatid goes to the other end of the cell for all 3
chromosomes.