Biology Grade 8 Finals

What is the skeletal system made up of?

bones

How many bones does the adult human skeleton have?

206

What is the longest bone in the body?

Femur (thigh bone)

What are the functions of the skeleton?

protection, support, movement

What are ligaments and what is their function?

fibres that connect two bones, hold the bones in place when they move

What is cartilage and what is its function?

it covers bones in a joint, prevents bones from wearing out as they rub against each other, reduces friction between bones

What are tendons and what is their function?

connect a muscle to a bone

What is synovial fluid and what is its function?

present in joints with a lot of movement, spreads over cartilage and acts like a lubricant reducing friction and wear and tear

What is the role of the pelvic girdle in the body?

supports the organs present in the thoracic and abdominal cavities

What are the types of joints and their functions?

hinge joint (elbow, knee) allows backward and forward movement, ball and socket joints (hip, shoulder) allow for much more movement

What is the function of the human heart?

The human heart is a pump that is centrally located in the thoracic cavity along with the lungs.

How many chambers does the human heart have?

The human heart has four chambers. The upper chambers are the auricles (also called atrium, plural is atria) and the lower chambers are the ventricles.

What is the function of the auricles and ventricles in the human heart?

The auricles are thin walled and the ventricles are thick walled. The left ventricle has the thickest wall.

What is the difference between the left and right side of the human heart?

The left side of the heart contains oxygenated blood while the right side contains deoxygenated blood.

What is the name of the valve between the right auricle and the right ventricle?

The valve between the right auricle and the right ventricle is called the right auriculoventricular valve or the tricuspid valve.

What is the function of the Pulmonary Semilunar Valve?

The valve at that controls the entry of blood in the pulmonary artery is called the Pulmonary Semilunar Valve.

What are the three types of blood vessels?

Arteries, veins and capillaries are the three blood vessels.

What type of blood do arteries carry?

Arteries carry oxygenated blood (exception is the Pulmonary artery as it carries deoxygenated blood).

What type of blood do veins carry?

Veins carry deoxygenated blood (exception is the Pulmonary vein as it carries oxygenated blood).

What are the two major functions of roots?

To anchor the plants in the soil and to absorb water and minerals from the soil

What are pneumatophores and where are they found?

Pneumatophores are breathing roots that grow above the soil and are found in plants that grow in marshy swamp areas like mangroves.

What are the main functions of the stem in a plant?

To transport water from the roots and food from the leaves, and to support the leaves and other aerial parts of the plant.

What are tendrils and what is their function?

Tendrils are thin, wiry, spring-like structures that curl around another plant to provide support.

What is the main function of leaves in a plant?

The main function of the leaves is to perform the function of photosynthesis.

What is the purpose of the modification of leaves in some desert plants?

The modification helps the plants to save water and also serves to protect the plants from being eaten by animals.

What is the purpose of the brightly colored and scented petals in a flower?

The petals are usually brightly colored and scented to attract insects for pollination.

What are the four whorls of a typical flower?

The four whorls are Calyx, Corolla, Androecium, and Gynoecium.

What is the male part of the flower called?

Androecium is the male part of the flower and is made up of stamens.

What is the female part of the flower called?

Gynoecium is the female part of the flower and is made up of the carpel (also called pistil).

What are the two main types of roots?

Tap roots and Fibrous Roots

What are some examples of plants with tap root systems?

Carrot, radish, beetroot, mango

What are some examples of plants with fibrous roots?

Grasses (rice, wheat), coconut, bamboo

What are adventitious roots?

Roots that arise from parts of the plant where roots are not expected to form

What are the functions of the nasal passage in the respiratory system?

Warming the air and preventing foreign particles from entering

What are the three purposes of the nose in the respiratory system?

The nose filters, warms, and moistens the air before it reaches the lungs.

What is the function of the trachea in the respiratory system?

The trachea, or windpipe, is supported by rings of cartilage and contains cilia to remove foreign particles.

What are bronchioles and what is their function?

Bronchioles are tiny tubes that result from the division of bronchial tubes. Their walls become thinner and have less cartilage, and they help in the exchange of oxygen and carbon dioxide between blood and air.

What is the role of alveoli in the respiratory system?

Alveoli are tiny air chambers at the end of bronchioles that facilitate the exchange of oxygen and carbon dioxide between blood and air.

How does the diaphragm contribute to the respiratory system?

The diaphragm is a strong wall of muscle that separates the chest cavity from the abdominal cavity. By moving downward, it creates suction to draw in air and expand the lungs.

What are the functions of the ribs in the respiratory system?

Ribs are bones that support and protect the chest cavity. They move to a limited degree, helping the lungs to expand and contract.

What is the role of genetics in the respiratory system?

Genetics play a role in the respiratory system through the study of chromosomes, including prokaryotic and eukaryotic chromosomes.

What is the structure of the chromosome in a prokaryote?

Circular DNA molecule, naked (not associated with proteins)

What are plasmids and where are they found?

Plasmids are smaller loops of DNA found in bacteria. They are not required by the cell in normal conditions but help the cell to adapt in unusual circumstances.

What is the difference between prokaryotic and eukaryotic chromosomes?

Prokaryotic chromosomes have one chromosome, while eukaryotic chromosomes have two or more different chromosomes. Prokaryotic chromosomes are circular DNA, while eukaryotic chromosomes are linear DNA.

What is the function of chromosomes in a cell?

Chromosomes are responsible for the transmission of hereditary information from one generation to the next because they contain the DNA molecule.

What are chromatids and how are they held together?

Each chromosome has two parts referred to as chromatids, which are identical to each other. The chromatids are held together at a point called the centromere, which occurs anywhere along the length of the chromosome.

What is the difference between diploid and haploid cells?

The nucleus of a diploid cell has pairs of homologous chromosomes, while a haploid cell has only one set of chromosomes. Cells of the human body are diploid as they have 23 chromosomes from the mother and 23 chromosomes from the father.

What is the representation of diploid cells?

2n

How many chromosomes do humans have in their diploid cells?

46

What is the representation of haploid cells?

n

What is the chromosome number in humans?

46

What type of reproduction do humans have?

Sexual Reproduction

What determines whether an individual is male or female in humans?

The 23rd pair of chromosomes (sex chromosomes)

What is the chance of a boy child being produced?

50%

What is the chance of a girl child being produced?

50%

What is the Punnet Square Method used for?

Determining the probability of offspring traits based on parental genotypes

What are the gametes for a male?

X, Y

What are the gametes for a female?

X, X

What is the significance of meiosis in sexual reproduction?

It ensures reproduction from diploid to haploid during gamete formation and promotes genetic variation

What is the significance of fertilization in promoting genetic variation?

Fertilization is a random process and promotes genetic variation by allowing random fusion of sperm and egg resulting in variation

What is the significance of meiosis in maintaining chromosome number?

Meiosis ensures maintenance of chromosome number and promotes variation

What is the purpose of meiosis in gametes?

Meiosis allows new combinations of genes to occur in gametes, leading to genetic variation in the offspring.

What is the function of the placenta?

The placenta separates the mother’s blood from the foetus blood, allows the foetus to take oxygen and nutrients, and facilitates the process of excretion of waste products.

How is the placenta attached to the developing foetus?

The placenta is attached to the developing foetus through the umbilical cord.

What is the gestation period in humans?

The length of the time between fertilization and birth is called gestation period in humans, and it is 280 days.

What is the purpose of the amniotic fluid?

The amniotic fluid acts as a cushion around the foetus, protects it from pressure outside the uterus, and allows the foetus to float freely for limb development.

What are the effects of smoking and drugs on fetal development?

Smoking and drugs can have detrimental effects on fetal development.

What are some of the health problems linked to smoking while pregnant?

premature birth, low birth weight, miscarriage, cot death, breathing problems, wheezing

How many children under the age of five are admitted to the hospital every year due to the effects of second hand smoke?

more than 17,000

What are some illegal drugs that can harm a baby?

cannabis, ecstasy, cocaine, heroin

What should pregnant women do before taking any new medication?

always check with your doctor, midwife or pharmacist

Which medicines and treatments are usually safe for pregnant women?

paracetamol, most antibiotics, dental treatments, some immunisations, nicotine replacement therapy

What are the two halves of the heart called?

The left side and the right side

What type of blood does the right side of the heart receive and pump?

Deoxygenated blood from the body

What type of blood does the left side of the heart receive and pump?

Oxygenated blood from the lungs

What are the upper chambers of the heart called?

Auricles or atria

What are the lower chambers of the heart called?

Ventricles

What type of blood vessels take blood away from the heart?

Arteries

What is the movement of an artery called?

Pulse

What are the smallest blood vessels called?

Capillaries

How thick is a capillary wall?

One cell thick

What are the components of blood?

Red Blood Cells, White Blood Cells, Lymphocytes, Platelets, Plasma

What is the function of Red Blood Cells?

Transport oxygen from lungs to different parts of the body

What is the function of White Blood Cells?

Help to fight infection and disease

What are Lymphocytes and what is their function?

WBC’s that attack bacteria and produce antibodies to fight against bacterial infection

What are platelets and what is their function?

Fragments of cells that help the blood to form a blood clot to prevent disease germs from entering the body and prevent loss of blood

What is the watery liquid of blood called?

Plasma

What does plasma contain?

Digested food, hormones, waste products like urea and carbon dioxide

What is the function of the pulmonary vein?

Transport oxygenated blood from the lungs to the heart

What is the function of the pulmonary artery?

Carry deoxygenated blood from the heart to the lungs

What is double circulation in the body?

Blood enters the heart and leaves the heart twice, forming two distinct circuits - pulmonary circuit and systemic circuit

What are the blood vessels of the heart called?

Coronary arteries and veins

What causes the formation of a thrombus in the arteries?

Fatty substances such as cholesterol sticking to the walls of the arteries, with calcium settling in the fatty layer and forming a raised patch

What is the result of thrombosis in the coronary artery?

Heart attack (Myocardial infarction = death of myocardial tissue in the heart)

What is the basic unit of life?

Cell

What does DNA stand for?

Deoxyribonucleic Acid

What is the DNA molecule made up of?

nucleotides

Where are chloroplasts found and what is their function?

found in the cytoplasm of plant cells

What is the function of mitochondria?

powerhouse of the cell

Where is the endoplasmic reticulum found?

in the cytoplasm of plant and animal cells