Mitosis and Eukaryotic Cells

• Mitosis enables cell division, creating two identical daughter cells.
• The importance of mitosis lies in growth, repair, and asexual reproduction.
• Mitosis occurs in eukaryotic cells, which contain a nucleus.

Stages of Mitosis:

• Interphase involves cell growth and DNA replication.
• During prophase, chromosomes become visible, and the nuclear membrane begins to break down.
• In metaphase, chromosomes align in the middle of the cell.
• Anaphase involves the separation of chromosomes to opposite sides of the cell.
• Telophase is marked by the formation of new nuclear membranes around each set of chromosomes.
• Cytokinesis is the division of the cell into two, resulting in two daughter cells.

Eukaryotic Cells:

• Eukaryotic cells are complex, possessing a nucleus and specialized structures called organelles.
• Plants, animals, fungi, and protists possess eukaryotic cells.

Key Parts of a Eukaryotic Cell:

• Nucleus: Contains the cell's DNA.
• Mitochondria: Produces the cell's energy (ATP).
• Endoplasmic Reticulum (ER): Aids in making and transporting proteins and lipids; can be rough (with ribosomes) or smooth (without ribosomes).
• Golgi Apparatus: Packages and sends out proteins and other molecules.
• Ribosomes: Responsible for making proteins.

Prokaryotic Cells:

• Prokaryotic cells are simpler and lack a nucleus; their DNA floats freely.
• Bacteria and archaea are composed of prokaryotic cells.

Key Parts of a Prokaryotic Cell:

• Cytoplasm: A jelly-like substance holding everything together.
• Plasma Membrane: The outer layer controlling what enters and exits the cell.
• DNA: Found in the nucleoid region.

The Penis (Male Reproductive System):

• The penis serves as the male reproductive organ, delivering sperm to the female reproductive system during intercourse.
• It also participates in urination.

Parts of the Penis:

• Glans: The rounded tip, often referred to as the head.
• Shaft: The main length of the penis.
• Urethra: A tube carrying urine and semen.
• Penile Tissue: Erectile tissue that becomes engorged with blood during an erection.

The Vagina (Female Reproductive System):

• The vagina is the female reproductive organ, connecting the uterus to the outside and serving as the entry point for sperm and the birth canal.

Parts of the Vagina:

• Vaginal Canal: Functions as the sperm passageway and the birth canal.
• Vaginal Opening: The entrance to the vagina.
• Cervix: The lower part of the uterus that opens into the vagina, expanding during childbirth.

Male Reproductive System:

• Testes: Produce sperm and testosterone.
• Vas Deferens: Tubes carrying sperm from the testes to the urethra.

Female Reproductive System:

• Ovaries: Produce eggs and estrogen.
• Fallopian Tubes: Transport eggs from the ovaries to the uterus; fertilization typically occurs here.
• Uterus: The site where a fertilized egg grows and develops into a baby.

Digestion:

• Digestion is the body's process of breaking down food into nutrients for energy, growth, and repair.

Key Parts of the Digestive System:

• Mouth: Breaks down food mechanically (chewing) and chemically (saliva).
• Esophagus: The tube carrying food to the stomach.
• Stomach: Breaks down food using acids and enzymes.
• Small Intestine: The primary site for digestion and nutrient absorption.
• Large Intestine: Absorbs water and salts from remaining food matter.
• Rectum and Anus: Expel waste from the body.

Compound and Monocular Microscopes:

• Microscopes are instruments for viewing objects too small to be seen with the naked eye.
• Monocular Microscope: Has one eyepiece, commonly used in classrooms for viewing plant cells or bacteria.
• Compound Microscope: Has two lenses (ocular and objective), providing higher magnification for viewing smaller details like cell structures.

Parts of a Microscope:

• Eyepiece (Ocular Lens): Magnifies the image.
• Objective Lenses: Lenses of varying magnifications (e.g., 4x, 10x, 40x) closest to the slide.
• Stage: The platform for placing the slide.
• Stage Clips: Secure the slide.
• Coarse Adjustment Knob: For focusing at low magnification.
• Fine Adjustment Knob: Used for fine-tuning at higher magnification.
• Condenser: Focuses light onto the specimen.
• Light Source: Provides light to view the specimen.
• Arm: Connects the tube to the base.
• Base: Supports the microscope.

Preparing a Wet Mount:

• Place a Drop of Water: Add a small drop of water to the center of the slide.
• Place the Specimen: Put the specimen in the drop of water.
• Cover with a Coverslip: Gently cover the specimen with a coverslip at a 45-degree angle to avoid air bubbles.
• Place the Slide on the Microscope: Position the slide on the stage and focus.

Cell Organelles:

• Organelles are structures within a cell that perform specific functions in eukaryotic cells.
• Chloroplasts (in plant cells): Contain chlorophyll for photosynthesis.
• Lysosomes: Break down waste and digest materials in the cell.
• Cytoplasm: The jelly-like substance that holds the cells organelles in place
• Cell Membrane: The outer layer of the cell that controls what enters and leaves

Flower Reproduction Types:

• Sexual Reproduction: Involves the fusion of male (pollen) and female (ovule) gametes through pollination.
• Asexual Reproduction: Produces offspring from a single plant without fertilization (e.g., cloning).

Parts of a Flower:

• Petals: Attract pollinators.
• Stamens (Male): Consist of the anther (produces pollen) and filament (supports the anther).
• Pistil (Female): Made up of the stigma (receives pollen), style (connects the stigma to the ovary), and ovary (contains ovules).
• Sepals: Protect the flower bud.
• Receptacle: The base where all parts attach.

Fertilization:

• External Fertilization: Occurs outside the female's body and is common in fish and amphibians.
• Example: Frogs release sperm and eggs into the water to fertilize.
• Internal Fertilization: Occurs inside the female's body and is typical in mammals, birds, and reptiles.
• Example: In humans, sperm is deposited inside the female’s vagina during intercourse, and the sperm travels to fertilize the egg inside the uterus.

In Vitro Fertilization (IVF):

• IVF helps couples struggling with natural conception with eggs taken from the ovaries, combined with sperm in a lab to form an embryo, and then transferred to the uterus.