Topic 1: Plant and body systems

3.1, 3.2, 3.3, 3.4, 3.6

List the levels of organisation in a multicellular organism

Cell → tissue → organ → organ system → organism.

Describe the process of cellular respiration

Glucose + oxygen → carbon dioxide + water + energy. Cellular respiration releases energy from food inside every living cell and happens in the mitochondria.

Label the parts of the respiratory system and describe the functions

Trachea (windpipe) — carries air from the throat to the lungs and is held open by rings of cartilage; bronchi — the two large tubes branching from the trachea into each lung; bronchioles — small tubes branching from the bronchi; alveoli — tiny air sacs where gas exchange happens; diaphragm — sheet of muscle below the lungs that contracts and relaxes to make you breathe.

Differentiate between inhalation and exhalation

Inhalation: the diaphragm contracts and moves down, the ribcage moves up and out, chest volume increases, air pressure decreases and air rushes in. Exhalation: the diaphragm relaxes and moves up, the ribcage moves down and in, chest volume decreases, air pressure increases and air is pushed out.

Explain gas exchange in animals (alveoli)

Gas exchange happens in the alveoli by diffusion. Oxygen moves from the air in the alveoli into the blood, while carbon dioxide moves from the blood into the alveoli to be breathed out.

Describe the adaptation of the lungs in facilitating gaseous exchange

The alveoli have a huge surface area, very thin walls that are only one cell thick, a rich blood supply and a moist lining. These features allow gases to diffuse efficiently.

Explain how the structure of the plant respiratory system relates to gas exchange

Plants exchange gases through stomata, which are tiny holes mostly on the underside of leaves. Gases diffuse through the stomata and the spongy layer of the leaf. Plants use diffusion only and do not have a pump like the heart.

Explain how the structures of the xylem and phloem relate to transportation of materials in plants

Xylem consists of dead, hollow cells strengthened with lignin and carries water and minerals upwards from the roots to the leaves. Phloem consists of living cells and carries sugar made in the leaves to the rest of the plant, both up and down.

Explain how transpiration in plants contributes to water and nutrient management

Transpiration is the evaporation of water from the leaves through the stomata. It creates a continuous pull of water up the xylem from the roots to the leaves, carrying water and minerals through the plant.

Compare plant and vertebrate systems for gas exchange and transportation of materials

Plants use stomata and the spongy layer for gas exchange, while mammals use alveoli. Plants use diffusion only, while mammals use diffusion followed by transport in the blood. Plants use xylem for water and phloem for sugar, while mammals use blood vessels and the heart. Both use diffusion across a large, thin, moist surface.

Compare the role and structure of arteries, veins and capillaries

Arteries carry blood away from the heart and have thick, muscular walls. Veins carry blood towards the heart, have thinner walls and valves to stop backflow. Capillaries are tiny vessels that are one cell thick, link arteries to veins and allow exchange with cells.

Label the parts of the heart and describe the functions associated with the part

Right atrium — receives blood from the body through the vena cava. Right ventricle — pumps blood to the lungs through the pulmonary artery. Left atrium — receives blood from the lungs through the pulmonary veins. Left ventricle — pumps blood to the body through the aorta. Vena cava — brings blood from the body to the heart. Pulmonary artery — carries blood from the heart to the lungs. Pulmonary veins — carry blood from the lungs to the heart. Aorta — carries blood from the heart to the body.

Describe the flow of blood in the body, specifically with the heart

Body → vena cava → right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta → body.

List the components of blood

Red blood cells, white blood cells, platelets and plasma.

Explain how the reproductive structures of plants relate to reproduction

The stamen is the male part of the flower and consists of the anther and filament. The anther produces pollen. The carpel/pistil is the female part and consists of the stigma, style and ovary. The stigma catches pollen, the style connects the stigma to the ovary, and the ovary contains the ovules. After fertilisation, the ovule becomes the seed and the ovary becomes the fruit.

Describe the spore formation and the different types of asexual reproduction in plants

Spores are single cells produced by plants such as ferns and mosses. They can be carried by wind and grow into new plants without fertilisation. Types of asexual reproduction include runners, tubers, rhizomes, bulbs, cuttings and spores. Asexual reproduction involves one parent and produces genetically identical offspring.

Describe sexual reproduction between flowering plants

Pollination is the transfer of pollen from the anther to the stigma. The pollen then grows down the style to the ovule, where fertilisation occurs. Fertilisation is when the male and female gametes join. After fertilisation, the ovule develops into a seed and the ovary develops into a fruit. Pollination can be self-pollination or cross-pollination.

Label parts of a flowering plant and describe methods of pollination and seed dispersal

Flower parts include anther, filament, petal, sepal, stigma, style, ovary and ovule. Pollination is the transfer of pollen from anther to stigma. It can occur by wind or animals such as insects and birds, and can be self-pollination or cross-pollination. Seeds can be dispersed by wind, water, animals eating fruit, hooks sticking to fur, or explosive pods.