Bio end of term 2

Haploid

Cells with one set of chromosomes (e.g., sperm and egg).

Diploid

Cells with two sets of chromosomes (e.g., somatic cells).

Meiosis I: Prophase I

Stage where chromosomes condense and crossing over occurs.

Meiosis I: Metaphase I

Homologous chromosomes line up in pairs.

Meiosis I: Anaphase I

Homologous chromosomes are pulled apart.

Meiosis I: Telophase I

Two cells form, each with half the original chromosomes.

Meiosis II: Prophase II

Chromosomes condense again.

Meiosis II: Metaphase II

Chromosomes line up single file.

Meiosis II: Anaphase II

Sister chromatids are pulled apart.

Meiosis II: Telophase II

Four haploid cells form.

Crossing Over

Exchange of genetic material between chromosomes in Prophase I, increasing variation.

Independent Assortment

Random lining up of chromosomes in Metaphase I, leading to different genetic combinations.

Mitosis vs. Meiosis

Mitosis involves 1 division for growth, meiosis involves 2 divisions to produce gametes.

Advantages of Sexual Reproduction

Genetic variation due to two parents.

Disadvantages of Asexual Reproduction

No genetic diversity; all offspring are clones.

Telomeres

Protective caps at the ends of chromosomes that prevent DNA damage.

Nondisjunction

Changes in chromosome number causing disorders like Down Syndrome.

Meristematic Tissue

Plant tissue responsible for growth found in roots and shoots.

Dermal Tissue

Protective outer layer of plants that prevents water loss.

Vascular Tissue

Plant tissue that transports materials; includes xylem and phloem.

Ground Tissue

Plant tissue that fills space between other tissues and is used for storage and support.

Stomata

Tiny openings in dermal tissue that allow gas exchange and control water loss.

Types of Roots - Taproot

A main root that reaches deep into the soil (e.g., carrot).

Types of Roots - Fibrous Roots

Many thin roots that spread out (e.g., grass); helps prevent soil erosion.

Types of Leaves - Simple Leaf

One single leaf blade (e.g., mango, guava).

Types of Leaves - Compound Leaf

Multiple leaflets on one stem (e.g., rose, neem).

Nastic Response

Non-directional movement in plants due to touch, temperature, or light.

Phototropism

Plant growth towards light.

Parthenogenesis

Development of an egg without fertilization, seen in some lizards and bees.

Gastrula

Stage where the blastula folds in to form three layers of tissue.

Ectoderm

Outer germ layer that develops into skin, brain, and nervous system.

Innate Behavior

Inborn, automatic behavior (e.g., spider spinning a web).

Learned Behavior

Behavior gained from experience or environment (e.g., dog sitting on command).

Imprinting

Type of learning that occurs at a young age (e.g., ducklings following the first object they see).

Axial Skeleton

Part of the skeleton that protects organs and supports posture; includes the skull and vertebral column.

Compact Bone

Dense bone structure that provides strength and protection.

Ball-and-Socket Joint

Allows movement in all directions (e.g., shoulder, hip).

Hinge Joint

Moves back and forth like a door hinge (e.g., knee, elbow).

Gliding Joint

Allows sliding movements (e.g., wrist, ankle).

Sutures

Fixed joints in the skull that hold bones together.