what's going on bessies in this video we're going to be tackling another portion of t7 Science and we're going to be talking about mitosis versus meosis and genetics let's get started so let's talk about the differences between mitosis and meiosis initially I approached learning about mitosis and meiosis as two distinct topics a direct comparison laid out side by side would have been significantly better and aided me in understanding it which is why I'm going to teach it like this today so what are the key differences well mitosis is actually going to lead to the formation of somatic cells also known as body cells well meiosis is going to produce reproductive cells known as gtes which is sperm and egg cells let's consider the initial state of a cell involved in both processes both are going to start off as a diploid cell designated by 2 N this just simply means that they contain two complete sets of chromosomes for humans this means that one set of 23 chromosomes were inherited from their mother and the other set of 23 chromosomes was inherited from their father totaling a total of 46 chromosomes during the interphase stage the cell replicates its chromosomes even after duplicating 46 chromosomes the chromosomes count is still referred to as 46 because the copies known as chromatis remain joined at the region called the centrair effectiv L doubling the chromatid number to 92 and although interface does precede both mitosis and meiosis it's not technically part of their process however it is a crucial phase for chromosome duplication setting the stage for the ultimate cell division that we're going to discuss and by the way illustrating a full 46 human chromosomes can be a little challenging so for the sake of clarity and ease visualization of our diagrams we're only going to use six chromosomes to help us understand these Concepts so in order to help us understand cell division we're going to use the acronym Pat which stands for the sequences of both mitosis and meiosis however the only difference is is that meiosis includes these stages twice resulting in each phase being designated with a numerical suffix like we see with prophase 1 metaphase 1 so on and so forth while we're going to outline the basic events that occur during the pmat stages for the aits it's really important for you to understand that everything we're talking about is barely scratching the surface of all the intricate details that are taking place when it comes to the aits this is what you're going to need to know so during mitosis prophase is going to be that initial stage when it comes to division it's indicated by the prefix of pro which means before this is when chromosomes become more visible as they condense ultimately becoming thicker in contrast prophase one of meiosis features not only chromosome condens but they're also going to start pairing up in hogus chromosomes these hogus chromosomes are roughly equal in size Gene type and location one came from the mother and one came from the father this stage is going to allow for the exchange of genetic material between chromosomes through a process called crossing over this is going to lead to the creation of recumbent chromosomes which are essential for genetic diversity next up we have metaphase so in mitosis that nuclear envelope that was previously enclosed in the nucleus has already been dismantled by the time that this phase begins a pneumonic when it comes to metaphase is we remember that m stands for Middle as during this phase the chromosomes are going to align in the cell center forming a single Row in contrast in metaphase 1 of meiosis while chromosomes are gathering in the cell's Central Area they're going to remain in those pair of their homologous counterparts therefore the alignment is not going to be a single row but rather a pair of chromosomes standing together in the middle during anaphase of mitosis a helpful pneumonic to remember that is to associate a with a way at this phase the chromatids are going to be separated and Drawn to opposite ends of the cell by spindle fibers in the context of meiosis anaphase 1 is going to mirror this concept but with a crucial distinction it is the chromosomes rather than the chromatids that're going to be moved away to opposite ends of the cell in both mitosis and meiosis specifically telophase one of meiosis chromosomes are going to reach the opposite sides of the cell and the process of forming new nuclear envelopes around these chromosome sets are going to begin setting the stage for the creation of two brand new cells each new nuclei is going to en capsulate the chromosomes on each side Paving the way for the cell to eventually divide into two separate entities following that nuclear division stage is cyto kinesis that is the partitioning of the cytoplasm is going to finalize that cell division process thus at the conclusion of mitosis and cytokinesis two genetically identical diploid cells are going to produce both having 46 chromosomes in humans this process is crucial for an organism's growth as generating more cells is going to be essential for development and for the repair and replacement of damaged cells well that's it for mitosis let's move on to meiosis part two so in prophase 2 we observe that the chromosones are condensing within both cells this phase is less eventful compared to prophase 1 primarily because there's no homologous pairs anymore undergoing crossing over in this stage during metaphase 2 the pneumonic M for the middle applies once again however in this phase the chromosomes are going to align in a single roll down the middle similar to the arrangement that we saw in metaphase of mitosis in anaphase 2 the pneumonic a for away is going to happen and in this stage the chromatids are going to separate themselves and are going to be drawn to opposite sides of the cells remember during the first stage they were still chromosomes now they are separating their chromosomes into cha tids so this is huge when it comes to meiosis anaphase part two during telophase 2 chromosomes are going to be moved to the furthest opposite ends of the cell and the formation of new nuclear envelopes are going to begin to encapsulate these new divisions leading to the creation of new cells following the completion of meiosis 2 cyto canis is going to occur dividing the cytoplasm entirely this is going to Mark the conclusion of meiosis resulting in four genetically distinct cells or gtes in this process males are going to produce sperm and females are going to produce egg cells all of them being haid cells carrying half the chromosome count of the original cell for humans each of these gametes contains 23 chromosomes notably the fusion of sperm and an egg cell creates a diploid cell or a fertilized egg known as a zygote this zy go is going to undergo numerous mitotic divisions leading to the development of a new organism let's do some practice questions during which phase of meiosis does crossing over occur contributing to genetic diversity by exchanging genetic material between homologous chromosomes is it a prophase 1 B metaphase 2 C anaphase 1 or D telophase 2 and the correct answer is a proas Phase 1 that crossing over occurs during prophase 1 of meiosis this is when those homologous chromosomes pair up and exchange segments of genetic material leading to genetic variation in resulting gametes which of the following statements accurately distinguishes between mitosis and meiosis in terms of genetic outcomes is it a mitosis results in two genetically identical Dio daughter cells while meiosis produces four genetically unique haid cells is it B both mitosis and meiosis result in four genetically identical daughter cells is it C mitosis produces four genetically unique diploid daughter cells whereas meiosis results in two genetic genetically identical haid cells or is it D both mitosis and meiosis produces two genetically unique diploid daughter cells and the correct answer is a mitosis results in two genetically identical diploid daughter cells well meiosis produces four genetically unique haid cells we talked about this a little bit before that mitosis when it comes to Cellular division is going to result in those two genetically identical diploid daughter cells essential for growth and repair and with biosis on the other hand that is a two-step division process that's going to result in those four genetically diverse haid cells also known as gtes which is is going to be crucial for sexual reproduction in meiosis homologous chromosomes segregate during anaphase 1 what is the significance of this event in terms of genetic variation is it a it ensures that each gami inherits an exact copy of each chromosome reducing genetic diversity is it B it results in the duplication of chromosomes increasing the chromosome number of gametes C it allows for the random assortment of chromosomes contributing to genetic diversity among Offspring or is it D it eliminates the need for crossing over as a means of generating genetic variation and the correct answer is C it allows for the random assortment of chromosomes contributing to genetic diversity among Offspring so during anaphase 1 of meiosis homologous chromosomes are pulled apart to each end of the cell this segregation allows for that random assortment of chromosomes meaning that each gam is going to receive a mix of maternal and paternal chromosomes this is really significant when it comes to assortment because this random assortment is going to contribute to that genetic diversity Among The Offspring as it produces a variety of potential genetic combinations so let's talk about heredity so heredity explores the transmission of traits from parents to their offspring a complex process that cannot be fully appreciated without a fundamental grasp of DNA chromosones genes and traits let's consider each one of us whose physical characteristics such as body patterns and size are determined by the genetic information coded in our DNA in addition to DNA environmental factors can also influence inherited traits for example our growth could have been impacted with insufficient nutrition contrary to the idea that DNA is a singular hidden code it's actually a widespread code present in the nuclei of almost all of our cells inherited from both our mother and our father another important note is that some animals have the ability to reproduce asexually meaning that an animal could have received all of its genetic material from just one parent if that were the case for some species nevertheless the essence Remains the Same DNA is responsible for coding the traits that Define us it's essential for self function and it influences everything we've come to know such as our height eye color risk for certain diseases and hair color let's talk about the structure of DNA it's not only beautiful but it's also pivotal in understanding the mechanism of inheritance DNA which also stands for deoxy ribonucleic acid falls into the category of nucleic acids one of our essential biomolecules composed of building blocks known as nucleotides nucleic acids feature three critical components a sugar named deoxy ribos a phosphate group collectively forming what is often referred to as the sugar phosphate backbone of DNA and most importantly we have a base it is the sequence of these bases that encode the genetic information that we've come to know directly correlating to the traits an organism exhibits in DNA we have four types of bases commonly abbreviated as a T C and G A stands for adenine T stands for thyine C stands for cytosine and G stands for guanine these bases pair up in a specific Manner and a well-known pneumonic can assist in Remembering these pairings we have apples in the tree stands for adenine is going to pair with thyine and then cars in the garage means that cytosine is going to pair with guanine this base pairing rule of these DNA bases is universal applying to all living entities from animals to plants protest as well as humans however the total number of DNA bases as well as the sequence in which these bases are arranged is going to vary depending on the different species and even individuals within those species underpinning the diversity of Life DNA consists of two strands with nucleotides aligned along each side of them in the center the bases of opposite strands are going to pair up connected by hydrogen bonds the structure of DNA is going to twist into what we know as a double helix shape segments of DNA constitutes genes which means specific regions of DNA corresponds to individual genes capable of encoding proteins we call these structural genes these proteins are going to play a crucial role when it comes to trait expression take human eye color for example it's a complex trait influenced by multiple genes which direct the production of proteins responsible for the pigmentation that we have in our eyes however proteins are going to influence far beyond just eye color it's also going to Encompass transport structural support enzymatic activity which is facilitating the synthesis of various substances defense mechanisms and so much more it's also important to note that not every Gene is going to be involved in protein synthesis DNA also contains non-coding regions these are what we like to call regulatory genes despite each of our body's cells containing a complete DNA code only specific Gene segments may be utilized with certain genes being activated and deactivated through various mechanisms this process is known as Gene regulation so your body contains a vast amount of DNA which when compacted is organized into structures we know as chromosomes this organization is particularly useful during cell division as it simplifies the process of Distributing DNA into new cells chromosomes consist of DNA coiled around a protein scaffold humans possess 46 chromosomes which means that almost every cell within our body carries the same number of chromosomes however when we talk about human gtes which is our sperm and our egg cells these particular cells only carry 20 2 3 chromosomes each consequently you inherit 23 chromosomes from your mother and another 23 chromosomes from your father which gives you a complete set of 46 chromosomes this constitutes your unique genetic code let's do some practice which of the following best explains the relationship between DNA genes and chromosomes within the context of heredity is it a genes are made up of chromosomes which are specific segments of DNA that Co code for proteins B chromosomes are composed of DNA and genes are specific segments of chromosomes that dictate individual traits is it C DNA replicates to form genes which then organize into chromosomes to be expressed as traits or is it D chromosomes replicate to produce genes which are then transcribed into DNA to determine hereditary information and the correct answer is B chromosomes are composed of DNA and genes are specific segments of chromosomes that dictate individual traits so remember chromosomes are very long strands of DNA wrapped around proteins called histones genes which are segments of DNA are located on these chromosomes and they're going to act as instructions to produce proteins these proteins are going to determine the characteristics or traits that can be passed from parents to offspring through heredity which of the following best describes the function of regulatory Gene in gene expression is it a they encode for proteins that are directly involved in metabolic reactions is it B they provide the code for structural components of the cell membrane is it C they produce proteins that help in the replication of DNA or is it D they produce proteins or RNA that controls the expression of other genes and the correct answer is D they produce proteins or rnas that control the expression of other genes so regulatory genes are responsible for producing proteins and rnas and they play a crucial role when it comes to controlling the expression of those genes within an organism so these regulatory molecules can either enhance or inhibit the transcription of Target genes thereby regulating gene expression in response to the cell's needs or external stimuli DNA often seems to hog the spotlight with its stunning double helix structure resembling that spiral laded appearance indeed DNA is crucial for storing genetic information and determining traits yet the significance of RNA frequently goes under appreciated RNA is essential for conveying genetic instructions to cells for protein production a process explored in depth when discussing protein synthesis ultimately it's a biomolecule just as pivotal as DNA and according to RNA World hypothesis RNA might have even predated DNA When comparing DNA and RNA it's notable that both are found across all forms of life in eukaryotic cells DNA is typically located inside of the nucleus whereas RNA is going to be present inside and outside of the nucleus Unlike DNA which has a double stranded appearance RNA is typically single stranded presenting with only one strand of nucleotides the sugar component differs between the two as well DNA contains deoxy ribos which aligns with its name deoxy ribonucleic acid indicating the absence of an oxygen molecule that's where the deoxy at the front of deoxy ribonucleic acid comes from in contrast rna's sugar is ribos reflecting in its name ribonucleic acid when it comes to nitrogenous bases RNA is going to include adenine urel cytosine and guanine did you notice something different urell replaces thyine found in DNA this substitution is going to call for a little bit of a tweak from The Familiar pneumonic that we learned about base pairings so instead of apples in the tree we're going to say apple under the tree that way it lets us know that adenine is going to pair with urisol when it comes to RNA when it comes to car and the garage that's still going to remain the same because we still have C cytosine and Quan pairs that are going to pair together when it comes to RNA it's crucial to understand that while DNA does hold the instructions for your traits it cannot be expressed without rna's intervention RNA plays a key role when it comes to translating DNA's genetic code into proteins that carry out numerous functions within our bodies there are three different types of RNA that's going to be important for you to know because of their roles mRNA also known as messenger RNA conveys genetic instructions derived from DNA in eukaryotic cells while DNA predominantly resides in the nucleus mRNA possesses the unique capability of exiting the nucleus this allows it to transport the genetic blueprint to the ribosome the cellular site for protein synthesis notably RNA is also significant structural component of ribosomes themselves RNA found in ribosomes is known as R RNA short for ribosomal RNA another crucial type of RNA is TNA which stand transfer transfer RNA whose primary function is to fairy amino acids to the ribosome ensuring that they align correctly with the corresponding mRNA codons as these amino acids are sequentially linked they form a polypeptide chain proteins which play a marod of roles within an organism are composed of one or more polypeptide chains protein synthesis unfolds through two principal phases transcription and translation a useful pneumonic to recall the sequence and steps involves noting the letters c in transcription and L in Translation since C precedes l in the alphabet it's easy to remember that transcription is going to occur before translation so starting with transcription it's going to involve converting DNA into a messenger strand this process is going to take place within the nucleus where the DNA is going to reside during transcription the enzyme RNA polymerase attaches matching RNA bases to the DNA templates these RNA bases are then linked together to create a single stranded molecule of mRNA messenger RNA is composed of an RNA sequence that mirrors the DNA template it's important to note that mRNA typically underg goes substantial editing before it's ready for action this editing process is both intriguing and essential when it comes to the correct functioning of the protein synthesis mechanism as we had previously noted one of the most notable advantages of being mRNA especially in UK carotic cells is the ability to exit the nucleus mRNA is going to travel from the nucleus into that cytoplasm where they're going to associate themselves with ribosomes ribosomes which are responsible for protein synthesis are comprised of R RNA which the r remember stands for ribosomal RNA making that pneumonic straightforward the next phase we encounter is translation and this is where the ribosome is going to assemble the protein so let's simplify the essentials of what occurs in the cytoplasm there you're going to find numerous TNA molecules at the ready TRNA which stands for Transfer RNA is responsible for carrying amino acids which are the fundamental building blocks of proteins as we're in the process of synthesizing proteins these amino acids are a crucial for construction the Assembly of a protein requires the aggregation of these amino acids which is a task orchestrated by our TRNA but exactly how does tRNA know which amino acid to collect this is where the role of mRNA becomes crucial the MRNA is going to serve as a guide determining which TRNA needs to be brought to the ribosome and consequently which amino acids need to be assembled to form our protein so each TRNA molecule is going to search for bases that match its own mRNA strand aiming to find a set that is going to be complementary upon locating these matching bases of the MRNA the TRNA is going to contribute its amino acid to the growing protein chain this matching process is going to involve reading that mRNA sequence in groups of three bases at a time not individually these groups of three are known as codons for instance tRNA molecules are going to encounter a codon of au UC of the MRNA while having a corresponding anti-codon of u a any TRNA with its anticodon is designated to carry the amino acid isoline when a TRNA possesses that UAG anti-codon pairs with a UAC codon on the MRNA it donates that isol leucine to the polypeptide chain after the transfer that TRNA is going to depart leaving behind its amino acid to incorporate into the protein this marks the addition of one amino acid before proceeding to interpret our next codon you might be wondering how do we determine that a TRNA matching the UAC codon is going to carry isoline well there's actually a codon chart that's going to become invaluable when you're trying to figure this out it's not necessary knowledge for you to know for the atits but it is important for you to understand the mechanism and the keys that are taking place when we're talking about protein synthesis revisiting our mRNA sequence let's decode the next codon which is G according to a codon chart the sequence specifies that the next amino acid should be aspartic acid the TRNA with its complimentary anti-codon which would have been CUA is going to to bind to the codone this TRNA is going to deliver that aspartic acid and after the transfer it's going to detach and connect to our original amino acid forming our polypeptide chain typically at some point the MRNA sequence is going to conclude with a stop codon so stop codons don't correspond with any amino acid instead they signal the ribosome to tell them that protein synthesis process is done and complete and they can release their Amino acid the outcome of the translation process is the creation of that amino acid chain it's going to be assembled in a specific sequence that was dictated by our mrna's code however it's crucial to remember that the sequence of mRNA is complementary to that of the DNA making DNA The Ultimate Guide when it comes to protein synthesis despite DNA playing a pivotal role the process cannot proceed without the crucial contribution of our mRNA R RNA and TRNA after that amino acid is assembled the protein May undergo further folding and modifications it might need to be transported to a different location inside of the cell these subsequent steps depending on the protein specific structure and function will take place so practice question which component is essential for initiating the transcription of a gene into mRNA in eukariotic cells is it a DNA ligase B RNA polyas C helicase or D ribosome and the correct answer is B RNA polyas onap Paras is crucial when it comes to the transcription process in eukariotic cells which reads the DNA sequence of a gene and synthesizes a complimentary mRNA strand DNA liase is more involved in DNA replication and repair not necessarily transcription helicase unwinds our DNA Helix during replication and ribosomes are the site of protein synthesis during translation not involved in the transcription process initiation so what is the role of mRNA in protein synthesis is it a it brings amino acids to the ribosome is it B it replicates DNA segments before protein synthesis is it C it serves as a template for assembling amino acids into proteins or D it transports proteins to different parts of the cell and the correct answer is C it serves as a template for assembling amino acids into proteins so during protein synthesis mRNA carries that genetic code from DNA during the transcription process to the ryome here is where it's going to serve as a template for the sequence of amino acids and a protein during translation TRNA not mRNA is responsible for bringing amino acids to the ribosome so option A would be wrong and then DNA replication and option b is a separate process from protein synthesis so again that doesn't make sense and then lastly with option D transporting proteins to different parts of the cell is a function of other cellular components like our endoplasmic micula and our GGI apparatus not mRNA I hope that this video is helpful in understanding the differences between mitosis versus meiosis and the complex topic of genetics as always if you have any questions make sure that you leave them down below I love answering your questions head over to nurse chunk store.com where there's a ton of additional resources that are available to you to help you Ace those ait's exams and as always I'll catch you in the next video bye