Prokaryotic and Eukaryotic Cells

• Fundamentals of Science is a Level 6 Certificate in Food Science and Technology

General Housekeeping

• Includes Attendance and Recordings, Learning Styles, Slides, Queries and Questions, and Breaks and Format

Module Format and Structure

• Classes include 5 classes and 2 Saturdays online
• Continuous assessment and the exam include a multiple-choice question (MCQ CA) 30%
• The date of the continuous assessment is 31.03.25
• The final exam is worth 70%

Module Content

• Biology covers Cell Structure and Function, Proteins and Analysis, Lipids, Carbohydrates, Nutrition, Enzymes, Quantitative Analysis, and Weights, Measures, and Preparation
• Chemistry covers Periodic Table, Chemical Bonds, Acids and Bases, and Elemental Analysis

Session 1

• Includes Cell Structure and Function, Proteins, and Protein Analysis
• There is a planned 10-minute break and a 15-minute break

Ways to Improve Learning and Engagement

• Focus on methods of learning, previous learning and experience, engagement and Learning tools, varying interests, and resource use

Learning Objectives for Session 1

• Identify structural differences between eukaryotic and prokaryotic cells, including methods of division
• Identify organelles and describe their functions

Cell Theory

• All organisms are composed of cells
• All cells come from pre-existing cells
• A cell is the smallest unit of life
• Cells fall into two major categories: prokaryotic and eukaryotic

Prokaryotic Cells

• Prokaryotic cells (bacteria) are smaller than eukaryotic cells
• Prokaryotic cell features:
  • Surrounded by membranes
  • Lack a nucleus
  • Genomic DNA is free-floating
• Prokaryotic cells divide by binary fission
• Bacteria can be classified as either Gram-positive (purple stain) or Gram-negative (pink stain)
  • This classification is based on staining and structure of the cell wall

Eukaryotic Cells

• Eukaryotic cells (fungi, plants, animals) are larger than prokaryotic cells
• Eukaryotic cells features:
  • Surrounded by membranes
  • Nucleus holds DNA
  • More complex than prokaryotic cells
• Eukaryotic cells divide by mitosis

Eukaryotic Cells: Organelles

• The cell, generally, contains the following organelles:
  • Mitochondria
  • Intermediate filament
  • Ribosomes
  • Rough endoplasmic reticulum
  • Nucleus
  • Nucleolus
  • Chromatin
  • Golgi apparatus
  • Golgi vesicle
  • Cytoplasm
  • Vacuole
  • Plasma membrane
  • Microtubule
  • Centrosome
  • Microfilament
  • Lysosome
  • Smooth endoplasmic reticulum
  • Secretory vesicle
  • Peroxisome

Characteristics of Eukaryotic Cells

• Key features:
  • The nucleus is enclosed within a nuclear membrane
  • The cell has mitochondria
  • Flagella and cilia are the organs used for motion
  • Contain a cytoskeletal structure
  • The nucleus contains DNA

Structure and Function of Eukaryotic Cells: Organelles

Plasma Membrane

• Separates the cell from the environment
• Comprises specific embedded proteins, which help in the exchange of substances in and out of the cell

Cytoskeleton

• Present inside the cytoplasm
• Consists of microfilaments, microtubules, and fibers
• Provides shape and structure, anchors organelles, and stimulates movement

Endoplasmic Reticulum

• There are two forms:
  • Rough ER contains ribosomes
  • Smooth ER lacks ribosomes

Nucleus

• The necleoplasm enclosed within the nucleus contains DNA and proteins
• The nuclear envelope consists of two layers (outer and inner membrane) and are permeable to ions, molecules, and RNA

Golgi Apparatus

• Packages protein and secretes proteins from the ER

Ribosomes

• The main site for protein synthesis

Mitochondria

• The powerhouse of the cell produces energy

Lysosomes

• Possess hydrolytic enzymes to digest protein, lipids, carbohydrates, and nucleic acids

Cilia and Flagella

• Allow for movement

Plasma Membrane

• Forms the outside of the cell, and controls the movement of molecules in both directions
• Composed of protein, phosphate, and lipid components, and has pores, receptors, and enzymes embedded in it
• Damage to the plasma membrane can induce cell death

Cytoskeleton

• Provides an important structural framework for the cell shape
  • Green: actin filaments
  • Red: microtubules
  • Blue: nuclei

Endoplasmic Reticulum

• There are two types
  • Rough ER contains ribosomes and performs protein synthesis
  • Smooth ER has no ribosomes and supports lipid and carbohydrate metabolism and detoxification
• Found in most types of eukaryotic cells
• The function is the synthesis and export of protein and membrane lipids, and varies between ER, cell type, and cell function

Nucleus

• Contains all the genetic information for the cells (DNA)
• Surrounded by a membrane, and has pores to control entry and exit of other molecules
• Limited access or mutation/damage to DNA causes death or disease

Golgi Apparatus

• Packages proteins into membrane-bound vesicles inside the cell
• Important for processing proteins for secretion from cells
• Addition of sugar by enzymes to proteins occurs as the proteins move through it

Ribosomes

• The location where cellular proteins are synthesized
• Found in the cytoplasm and forms part of the Endoplasmic reticulum (ER)
• A message from the nucleus goes to the ribosome
• Amino acids join and form a peptide, which is released from the ribosome and then functions in the cell/body

Mitochondria

• Considered the powerhouse of the cell
• Produces energy-rich molecules (ATP) from food molecules
• Present in almost all eukaryotic cells
• Injury to the mitochondria triggers cell death
• Contains enzymes to detoxify agents

Lysosomes

• Called breakdown bodies within cells
• Small vesicles (bubbles) produced by the Golgi apparatus that contain digestive enzymes
• Functions:
  • Digest food
  • Destroy bacteria (in white blood cells)
  • Recycle damaged organelles
  • "Suicide packs" causes programmed cell death

Cilia and Flagella

• Move liquid past the surface of the cell.
• Allows single cells, like sperm, to swim

Polymers for Life

• Polymers are made from monomers
  • Carbohydrates (sugars)
  • DNA & RNA
  • Lipids (fats)
  • Proteins

DNA: Deoxyribonucleic Acid

• There are four types of nucleic acids:
  • Adenine (A)
  • Guanine (G)
  • Cytosine (C)
  • Thymine (T)
• Polymers are linked together using A-T or G-C by hydrogen bonds

DNA: Deoxyribonucleic Acid

• Composed of two linked strands that wind to resemble a twister ladder 'double helix'
• A chromosome is tightly coiled around proteins called histones to support its structure

Cell Division: Mitosis

• Cells divide when an organism grows, and becomes damaged and needs new cells for repair
• Organisms like bacteria reproduce asexually
• New cells must contain genetic information identical to the parent cell
• During mitosis, two identical cells, called daughter cells, are produced from each parent cell

Stages of Mitosis

• Interphase: The cell spends most of its time in interphase. The DNA in chromosomes copies itself, ready for mitosis
• Prophase: The DNA condenses to become more visible, and the membrane around the nucleus disappears
• Metaphase: Chromosome and their copies line up in the middle of the cell
• Anaphase: Chromosomes and their copies are pulled to opposite ends of the cell
• Telophase: New membranes form around the chromosome at each end of the cell
• Cytokinesis: The pinching of the cell membrane divides into two daughter cells

Cancer and Carcinogens

• Cells grow and divide by mitosis only when new cells are needed
• Usually, happens when someone is growing or we need to replace old or damaged cells
• Cancer occurs when cells begin to grow and divide uncontrollably
• Cancerous cells produce a growth called a tumor

Review Questions

• What are the two basic categories/ types of cells?
• The difference between the two?
• 5 Organelles and their function?
• What is a chromosome?
• What are the 5 stages of mitosis?

Explore the fundamental differences between prokaryotic and eukaryotic cells, including cell division methods, key characteristics, and unique components. Includes protein synthesis and organelles functions.