Complete Cell Unit in One Shot | Cell | Cell Cycle | Biomolecules | NEET 2024 | Seep Pahuja

Unacademy NEET2 minutes read

The session focuses on three crucial chapters for NEET UG preparation, with 5-6 questions expected from each chapter in the exam, totaling up to 11 questions. It covers topics like cell division, cell structure, prokaryotic and eukaryotic cells, and essential biomolecules, emphasizing active participation and unique revision methods for effective preparation.

Insights

  • Three crucial chapters for NEET UG preparation are Cell - The Unit of Life, Cell Cycle and Cell Division, and Biomolecule, with 5-6 questions expected from each in the exam.
  • Key topics in Cell Cycle and Cell Division include Prophase, L Jud, PD, and D.
  • The weightage of these chapters in the exam ranges from 3 to 5 questions each, totaling up to 11 questions.
  • Prokaryotic cells lack membrane-bound organelles and a proper nucleus, while Eukaryotic cells have these features.
  • The Fluid Mosaic Model explains the plasma membrane's structure, with lipids being fluid and proteins moving laterally, facilitated by protein movement.
  • The cell cycle involves distinct phases like G1, S, G2, and M, regulated by checkpoints that can lead to cell cycle suspension or entry into the G0 phase if not passed.

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Recent questions

  • What are the key topics in Cell Cycle and Cell Division?

    Prophase, L Jud, PD, and D are key topics.

  • What is the significance of the Unit of Life in biology?

    The Unit of Life marks the beginning of the subject.

  • How many questions can be expected from the three crucial NEET chapters?

    5-6 questions expected from each chapter.

  • What is the main arena of all activities in a cell?

    Cytoplasm is the main arena of all activities in the cell.

  • What distinguishes prokaryotic cells from eukaryotic cells?

    Prokaryotic cells lack membrane-bound organelles and a proper nucleus.

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Summary

00:00

NEET UG Biology: Cell, Cycle, Biomolecule Essentials

  • The session will cover three chapters: Cell - The Unit of Life, Cell Cycle and Cell Division, and Biomolecule, with a focus on NEET UG preparation.
  • These three chapters are crucial for NEET, with 5-6 questions expected from each in the exam.
  • Prophase, L Jud, PD, and D are key topics in Cell Cycle and Cell Division.
  • The Unit of Life is fundamental in biology, marking the beginning of the subject.
  • The weightage of these chapters in the exam ranges from 3 to 5 questions each, totaling up to 11 questions.
  • Cell Cycle questions may include sequence-based, event-based, or matching questions.
  • The session emphasizes active participation and engagement from students.
  • The upcoming sessions will focus on revising the entire biology syllabus in a unique and efficient manner.
  • A special method involving micro super notes will be used for quick and effective revision.
  • A discount offer is available for subscriptions, providing access to various live batches and courses.

13:26

Cell Structure and Function in Brief

  • Cytoplasm is the main arena of all activities in the cell.
  • Prokaryotic cells lack membrane-bound organelles and a proper nucleus.
  • Eukaryotic cells have membrane-bound organelles and a proper nucleus.
  • Both prokaryotic and eukaryotic cells have cytoplasm and DNA.
  • Ribosomes are found in the cytoplasm, mitochondria, and chloroplasts.
  • The size of a typical bacteria ranges from 1 to 2 micrometers.
  • Prokaryotic cells have three layers: plasma membrane, cell wall, and glycocalyx.
  • Glycocalyx serves for protection, attachment, and immunity to bacteria.
  • The cell wall of bacteria is made of peptidoglycan, amino acids, and sugar.
  • Bacteria can move using basal bodies, hooks, and filaments.

26:56

Prokaryotic and Eukaryotic Cell Structures Explained

  • Prokaryotic structures include Pilae and Fimbriae, which aid in motility but are non-thick structures.
  • Pilae and Fimbriae do not assist in motility but help in sticking to surfaces.
  • Inclusion bodies store reserve material in the cytoplasm, such as Phosphate Granules and Cyanoflam Granules.
  • Prokaryotic Vacuoles are not membrane-bound, except for gas vacuoles, which are pseudo vacuoles.
  • Prokaryotic cells have two subunits, 70s and 80s, with the larger subunit being 50s.
  • Ribosomes in prokaryotic cells translate mRNA to proteins, forming Polysomes or Polyribosomes.
  • Eukaryotic cells have membrane-bound organelles, a proper nucleus, and are distinct from prokaryotic cells.
  • Plant cells have a cell wall made of cellulose, plastids for photosynthesis, and lack centrioles.
  • The plasma membrane in all cells is composed of lipids, proteins, cholesterol, and carbohydrates.
  • The Fluid Mosaic Model explains the plasma membrane's structure, with lipids being fluid and proteins moving laterally.

41:23

Proteins and Membranes: Cell Function and Structure

  • Proteins can rotate on their own axis, potentially flipping upside down.
  • Proteins can be left or right-handed, allowing for movement on their own axis.
  • Fluid cells benefit from protein movement, creating space for growth and endocytosis.
  • Cell division and intercellular junction formation are facilitated by proteins.
  • The phospholipid layers inside and outside cells differ due to environmental factors.
  • Integral and peripheral proteins play distinct roles in cell function.
  • Proteins with hydrophobic tails facilitate molecule entry through the membrane.
  • Cholesterol and oligosaccharides stabilize the membrane and aid in transport.
  • The cell wall provides structure, protection, and interaction between cells.
  • Algae, plants, and fungi have distinct cell wall compositions and structures.

56:03

Cellular Organelles: Functions and Importance

  • Lysosomes are organelles responsible for digestion within cells.
  • Golgi apparatus is involved in the formation of lysosomes.
  • Enzymes present in lysosomes aid in digestion.
  • Primary lysosomes become active when food particles are mixed with them.
  • Secondary lysosomes are formed when digestion is complete.
  • Undigested material becomes waste within the cell.
  • Residual bodies are removed through exocytosis to prevent diseases like gouty arthritis.
  • Autophagic lysosomes are responsible for breaking down old organelles.
  • Vacuoles play a role in the endomembrane system, with tonoplast being a crucial membrane.
  • Plastids in plants, including chloroplasts, chromoplasts, and leucoplasts, have distinct functions in storing carbohydrates, oils, and proteins.

01:10:19

Cell Structures and Functions Explained

  • Some bacteria have mitochondria and chloroplasts.
  • The name of a movie came up during a discussion.
  • The structure of ribosomes was explained, including their presence in various cell components.
  • Ribosomes are involved in protein synthesis when attached to mRNA.
  • The cytoskeletal structure provides mechanical support, motility, and cell shape.
  • The structure and function of cilia and flagella were discussed, including the basal body formation.
  • The centriole structure and its role in cell division were explained.
  • The nucleus, discovered by Robert Brown, is the brain of the cell.
  • The nucleus contains a nucleolus, which is the site of active ribosomal RNA synthesis.
  • Chromatin, consisting of DNA and proteins, can be densely packed (heterochromatin) or loosely packed (euchromatin) based on activity levels.

01:25:08

"Chromosome Structure and Cell Cycle Overview"

  • A method is described for creating a condensed chromosome structure named centro mier.
  • The primary construction of the chromosome is centered around centro mier.
  • Chromosomes have four types based on the position of centro mire: meta centric, acrocentric, and telocentric.
  • Spindle fibers attach to a proteinaceous disk named Kineto.
  • Chromosomes with both primary and secondary construction are termed satellite chromosomes.
  • Heterochromate staining indicates active transcription in chromosomes.
  • Satellite chromosomes in humans include pairs 13, 14, 15, 21, and 22.
  • Nucleolar Organizer Region (NOR) is a secondary construction in chromosomes.
  • The cell cycle involves DNA synthesis, cell growth, and division, taking 24 hours in human cells.
  • The cell cycle consists of two phases: the preparatory interface phase and the actual division M phase.

01:39:31

Cell Cycle Phases and Checkpoints Explained

  • The cell cycle consists of distinct phases: G1, S, G2, and M, with M phase further divided into karyokinesis (nuclear division) and cytokinesis (division of cytoplasm).
  • Karyokinesis is subdivided into prophase, metaphase, anaphase, and telophase.
  • Mnemonic "man, mommy's some butt" aids in remembering the phases but isn't essential.
  • The cell cycle is a genetically controlled process, progressing in a specific order: G1, S, G2, and M.
  • G1 is the longest phase of interphase, crucial for cell growth and organ duplication.
  • S phase involves DNA replication without changing chromosome number but doubling DNA content.
  • G2 phase sees mitochondria and chloroplast duplication, RNA and protein synthesis, and histone protein duplication.
  • Checkpoints in the cell cycle, like between G1 and S, regulate progression through cyclin and CDK proteins.
  • Failure to pass checkpoints can lead to cell cycle suspension or entry into the G0 phase, where cells are metabolically active but not dividing.
  • Meristematic cells exemplify the ability to re-enter the cell cycle when needed, transitioning to parenchyma or secondary meristem cells.

01:54:14

Cell Division: Mitosis and Meiosis Explained

  • Mitosis occurs in diploid cells, leading to the creation of diploid cells through mitosis.
  • Mitosis is present in all cells, creating daughter cells with the same number of chromosomes as the parent cell.
  • Mitosis involves phases like prophase, metaphase, anaphase, and telophase, each with distinct characteristics.
  • Centrosomes play a crucial role in mitosis, forming astral rays and spindle fibers.
  • Mitotic appetite refers to the condensation of chromosomes in early prophase.
  • Cytokinesis follows mitosis, involving the division of cytoplasm through cell furrow formation.
  • In plants, cell plate formation occurs during cytokinesis, leading to the creation of two cells.
  • Meiosis involves reduction division, creating daughter cells with half the number of chromosomes as the parent cell.
  • Meiosis includes stages like leptotene, zygotene, pachytene, diplotene, and diakinesis, each with specific functions.
  • Synaptic complexation and crossing over occur during meiosis, leading to genetic recombination and the formation of tetrads.

02:10:44

Chromosome Formation in Dia Kinesis

  • 'Kaj Mitta' refers to the stage where chromosomes form structures during Dia Kinesis.
  • Dia Kinesis is characterized by the terminalization of chromosomes.
  • Spindle fibers disappear, indicating the beginning of miosis.
  • Pro Phase One involves Lata Jalta Paani and understanding five key concepts.
  • Crossing over and tetradotoxin are significant in this phase.
  • Terminalization occurs, resulting in two chromatids on one chromosome.
  • Meta phase involves aligning homolographic chromosomes in two plates.
  • 46 spindle fibers align with 23 pairs of chromosomes.
  • Anaphase sees the separation of centro mier and chromated.
  • Dyad formation results in two cells with 23 chromosomes each.

02:25:46

Ash Analysis and Metabolism in Biochemistry Text.

  • Ash analysis involves testing for sodium ion, potassium ion, calcium ion, chloride, and other elements present in cells.
  • To conduct ash analysis, start by taking a tissue sample with water, determining wet weight, air drying it to obtain dry weight, and then setting it on fire to analyze carbon combustion.
  • After combustion, the remaining ashes contain inorganic chemicals like sodium, potassium, and chloride, while the carbon is lost.
  • The next step involves taking the sample to a lab for further analysis to determine the quantities of sodium, potassium, and other elements present.
  • Understanding ash analysis is crucial for comprehending cell composition, as taught in Bio Micro Molecules.
  • The chemical compound tri chloroacetic acid (Cl3CCOOH) is used in filtration processes, resulting in a retentate or acid-insoluble substance.
  • Metabolism involves primary reactions like respiration and photosynthesis, where substrates are used to produce products, distinguishing between primary and secondary metabolized compounds.
  • Primary metabolized compounds have a direct role in essential functions like growth and development, while secondary metabolized compounds are byproducts with no direct function.
  • Secondary metabolized compounds include pigments like carotene, anthocyanin, alkaloids, morphine, and terpenes, which have various applications in drugs, dyes, and essential oils.
  • Understanding the distinctions between primary and secondary metabolized compounds is crucial for answering questions related to biochemistry and chemistry exams.

02:41:21

"Carbon, Glucose, and Sugars: A Summary"

  • Carbon is present in six places, with a ring having five positions occupied by carbon and one position outside the ring.
  • The ring with six carbons is called a pyran ring, specifically in glucose.
  • Glucose can be classified as alpha or beta based on the position of the O group in the first carbon.
  • Grapes are the only fruit that does not contain fructose, making it unsuitable for diabetic individuals.
  • Fructose and glucose have similar formulas but differ in the presence of an aldehyde group in glucose.
  • Fehling's and Benedict reagents are used to test for reducing sugars, with a color change from blue to red indicating a positive result.
  • Deoxyribose can be derived by removing the O group from the second carbon in ribose.
  • Mono-saccharides are generally reducing sugars, detected through Fehling's reagent turning red upon interaction.
  • Glucose and fructose combine to form sucrose, a non-reducing disaccharide due to the absence of a free aldehyde group.
  • The glycosidic bond between glucose and fructose in sucrose makes it non-reducing, unlike mono-saccharides.

02:56:40

Sugar Polymers and Their Properties

  • Ketone occurs only at the second carbon
  • Vela is not present, indicating non-reducing sugar
  • Lactose is superior to glucose plus galactose
  • Glucose Plus is made from galactose
  • Toothpaste contains a reducer, salt
  • Sucrose is a non-reducing sugar
  • Multocida is a reduced sugar
  • Starch is a homopolymer of glucose
  • Cellulose is a structural polymer made of glucose
  • Inulin is a polymer of fructose, a beta polymer

03:10:51

Effective Study Tips: Micro Notes, Handwritten Retention

  • Micro notes and NCRT are essential for studying effectively.
  • Emphasize handwritten notes over typed notes for better retention.
  • Proteins are made from amino acids, with different types of amino acids available.
  • Amino acids are classified into neutral, acidic, and basic categories.
  • The net charge of amino acids in solution determines their nature.
  • Essential amino acids must be obtained from diet, while non-essential amino acids can be synthesized by the body.
  • There are 10 essential amino acids that must be acquired through diet.
  • Semi-essential amino acids can be synthesized by the body in adulthood.
  • Essential amino acids are crucial for children's nutrition.
  • Glycine plays a significant role in the formation of hemoglobin and melatonin.

03:23:46

"Proteins and Amino Acids: Essential Elements"

  • The pineal gland produces the hormone melatonin, crucial for regulating sleep cycles.
  • T3, T4, and adrenaline are precursors of melanin and histamine.
  • Amino acids are essential for protein synthesis and are classified as essential or non-essential.
  • Proteins are formed from 20 standard amino acids, requiring peptide bonds for their structure.
  • Proteins are heteropolymers, unlike homo polymers like starch or glycogen.
  • The primary structure of proteins involves a linear chain of amino acids with specific positional information.
  • Secondary structures like alpha helix, beta plated sheets, and triple helix are formed through hydrogen bonds.
  • Tertiary folding of proteins involves weak and strong bonds, making the protein functional.
  • Oligomeric proteins have multiple chains joined by bonds, forming a quaternary structure.
  • Amino acids are also known as substituted methane due to their chemical structure.

03:37:58

"Serine and Lipids: Biomolecules Explained"

  • Serine is a hydroxy methyl amino acid with ionizable and aromatic properties, existing in various forms including the Twitter ion form with both negative and positive charges.
  • Lipids, the next biomolecule discussed, are not strict polymers but small molecules that form vesicles in the retentate fraction due to their solubility in polar solvents like benzene and chloroform.
  • Lipids are essentially esters formed by combining fatty acids and glycerol through ester bonds, with saturated fatty acids having single bonds and unsaturated ones containing double or triple bonds.
  • Saturated fatty acids like palmitic acid have single bonds, while unsaturated ones like oleic acid have double bonds, with polyunsaturated fatty acids having more than two double bonds.
  • Lipids are categorized into simple lipids, containing only fatty acids and alcohol, complex lipids with additional groups like phosphates, and sterols like cholesterol, each with distinct properties and examples like beeswax, phospholipids, and cholesterol.
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