PI Life Sciences Notes

Flashcards based on lecture notes for exam preparation.

What is the function of a root hair?

An epidermal outgrowth that increases the surface area for water and mineral absorption from the soil.

What is the endodermis?

A layer of cells in roots that regulates the passage of water from the cortex into the xylem.

What is the pericycle?

The plant tissue from which lateral roots originate.

What is secondary thickening?

The process by which dicot stems grow thicker over time, forming annual rings of xylem tissue.

Define transpiration.

The loss of water vapour from the aerial parts of a plant, mainly through the stomata.

What is guttation?

The process where water droplets are excreted from leaf margins through hydathodes under high root pressure.

What is a hydrostatic skeleton?

A skeleton formed by fluid-filled chambers that provide support through internal pressure (e.g. in earthworms).

Define endoskeleton.

An internal skeleton made up of living bone and cartilage tissue, found in vertebrates.

What is compact bone?

Dense bone tissue that forms the outer layer and shafts of long bones, providing strength and support.

What is spongy bone?

A lighter, porous bone tissue at the ends of long bones that contains red marrow for blood cell production.

Define sarcomere.

The region between two Z-lines in a muscle fibre

What is an open circulatory system?

A system where blood is pumped into body cavities and bathes organs directly, found in arthropods and molluscs.

What is a closed circulatory system?

A system where blood is contained in vessels and pumped by the heart to reach all body tissues.

What is the pericardium?

A double-layered membrane surrounding the heart with fluid between layers to reduce friction.

What are the functions of the root?

To absorb water and minerals from the soil and anchor the plant in place.

What are the functions of the stem?

To support leaves, flowers, and fruits, transport water and organic substances, and store nutrients and water.

What is the function of xylem?

To transport water and mineral salts from the roots to the rest of the plant and provide structural support.

What is the function of phloem?

To transport manufactured organic substances from the leaves to other parts of the plant.

What are the functions of the vertebral column?

Support the head, protect the spinal cord, attach ribs and muscles, allow spinal nerves to pass, absorb shock, and aid balance.

What are the functions of cartilage?

To cushion joints, reduce friction, maintain flexibility, and support structures like the ears and nose.

What are the functions of tendons?

To attach muscle to bone and enable movement.

What are the functions of ligaments?

To connect bone to bone and stabilise joints.

What are the functions of skeletal muscles?

Voluntarily contract to produce movement and work in antagonistic pairs for joint control.

What are the functions of the circulatory system?

To transport gases, nutrients, and waste; regulate temperature; and provide immune protection.

What are the functions of the heart valves?

To ensure one-way flow of blood and prevent backflow during heart contractions.

What are the external parts of a dicot root?

Lateral roots, mature region, root hairs, elongation region, meristematic region, and root cap.

What are the internal parts of a dicot root?

Epidermis, parenchyma, endodermis, and pericycle.

What is the elongation region of the root responsible for?

It is where new cells elongate to increase root length.

What is the role of the root cap?

It surrounds and protects the growing tip of the root.

What tissue forms lateral roots?

The pericycle.

What does the activity sheet on plant roots ask students to do?

Identify parts on an external root diagram, name functions, differentiate tissues, explain modifications, and identify central cylinder components.

What are the external parts of a dicot stem?

Terminal bud, axillary buds, nodes, and internodes.

What are the internal parts of a dicot stem?

Epidermis, collenchyma, parenchyma, endodermis, xylem (inside vascular bundles), and phloem (outside).

What are annual rings in dicot stems?

Concentric rings of thick-walled xylem vessels seen in woody stems due to secondary thickening.

What adaptations limit transpiration in leaves?

Waxy cuticle, reduced leaf area, stomatal closure, and sunken stomata.

What are the three categories of ribs in the human rib cage?

True ribs (7 pairs), false ribs (3 pairs), and floating ribs (2 pairs).

How many vertebrae are in the vertebral column and how are they distributed?

33 total: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccyx.

What are the main regions of a typical vertebra?

Centrum (body), neural arch, spinal canal, neural spine, and transverse processes.

What do articular surfaces on vertebrae allow?

Articulation with adjacent vertebrae and the ribs (in thoracic vertebrae).

What are the types of bones in the human body?

Long, short, flat, and irregular bones.

What is the structure of a long bone?

Diaphysis (shaft), epiphysis (ends), periosteum, compact bone, marrow cavity (with yellow marrow), spongy bone (with red marrow), and hyaline cartilage.

What are myofibrils composed of?

Alternating thick myosin filaments and thin actin filaments.

What gives skeletal muscle its striated appearance?

The alternating pattern of light (actin only) and dark bands (overlap of actin and myosin).

How does a muscle contract?

Nerve impulses cause actin to slide past myosin, shortening the sarcomere and the entire muscle fibre.

What is the passage of blood through the heart and body?

Vena cavae → right atrium → right ventricle → pulmonary arteries → lungs → pulmonary veins → left atrium → left ventricle → aorta → body.

Why is the left ventricle wall thicker than the right?

Because it needs to pump oxygenated blood to the entire body under high pressure.

What are coronary arteries and veins responsible for?

Supplying oxygen-rich blood to and removing deoxygenated blood from the heart muscle.

Why do semilunar valves close after ventricular contraction?

To prevent the backflow of blood into the ventricles from the arteries.

Impulses travel from the…

dendrite to axon

What are fibrous joints and give an example?

Fibrous joints (e.g. sutures) are immovable and connect bones using dense connective tissue.

What are cartilaginous joints and give an example?

Cartilaginous joints (e.g. those in the spine) are partially movable and connect bones with cartilage.

What are synovial joints?

Synovial joints are freely movable and are characterised by a fluid-filled space between the bones.

What is transpiration in plants?

Transpiration is the process of water movement through a plant and its evaporation from aerial parts, primarily the leaves.

What is translocation in plants?

Translocation is the movement of organic materials from the source to the sink within the plant.

What is the diaphysis in a long bone?

The diaphysis is the long, cylindrical middle part (shaft) of a long bone.

What is the epiphysis in a long bone?

The epiphysis is the end part of a long bone, found at both ends of the diaphysis.

What is the periosteum?

The periosteum is a strong, tough membrane that surrounds a long bone.

What makes up the shaft of a long bone?

The shaft is made up of compact bone that surrounds a longitudinal cavity known as the marrow cavity.

What is the endosteum?

The endosteum is a thin, soft membrane that lines the marrow cavity inside a long bone.