Life Sciences Grade 11 Lecture Notes

Practice flashcards covering micro-organism classification, plant/animal biodiversity, human anatomy, physiology, and population ecology based on Grade 11 Life Sciences notes.

Into which five kingdoms are all living organisms divided?

Monera (bacteria), Protista, Fungi, Plantae, and Animalia.

What characterizes the DNA in prokaryotes compared to eukaryotes?

In prokaryotes, DNA is not enclosed by a nuclear membrane and occurs freely in the cytoplasm, whereas in eukaryotes, DNA is enclosed by a nuclear membrane inside the nucleus.

Why are viruses considered acellular?

They have no cell structure, meaning they possess no nucleus, cytoplasm, or organelles, and are not classified as prokaryotes or eukaryotes.

What is a bacteriophage?

A virus that infects a bacterial cell.

What are the four common shapes of bacteria?

Rod-shaped ($bacillus/bacilli$), spherical/round ($coccus/cocci$), spiral-shaped ($spirillum/spirilla$), and comma-shaped ($vibrio$).

What are the three categories of heterotrophic bacteria?

Parasitic bacteria, Saprophytic bacteria, and Mutualistic bacteria.

Into which three main groups are Protists divided?

Protozoa (animal-like), Algae (plant-like), and Slime and water moulds (fungus-like).

What material makes up the cell walls of all fungi?

Chitin.

What is the vegetative body of a multicellular fungus like Rhizopus called?

The mycelium, which is formed by interwoven masses of branched filaments known as hyphae.

Which organism is responsible for producing $50\%$ of the Oxygen produced by photosynthesising organisms?

Algae.

What role does the bacterium Escherichia coli ($E. coli$) play in the human intestine?

It produces vitamin $K$, which is important for blood clotting, and certain $B$ vitamins.

Which specific cells are infected and destroyed by the Human Immunodeficiency Virus ($HIV$)?

$CD4$ cells of the human immune system.

What is the causative agent of Tuberculosis ($TB$)?

$Mycobacterium\,tuberculosis$.

Which organism acts as the primary host and vector for the malaria parasite?

The female $Anopheles$ mosquito.

What are the two main categories of immune response?

Natural immunity (present at birth) and Acquired immunity (developed through exposure).

What term describes the use of recombinant DNA technology to make bacteria produce human insulin?

Biotechnology.

What are the four main divisions of the Kingdom Plantae?

Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms.

Define 'Alternation of Generation' in plant life cycles.

The phenomenon where a sexual gametophyte generation alternates with an asexual sporophyte generation.

What is the dominant generation in Bryophytes?

The gametophyte generation.

What is the name of the underground stem found in Pteridophytes (ferns)?

A rhizome.

What does the term 'Gymnosperm' literally mean?

Naked seed ($gymnos = naked$; $sperm = seed$).

What structure protects the flower during the bud stage?

The sepals, which collectively form the calyx.

What are the two types of pollination?

Self-pollination and Cross-pollination.

What is the function of the endosperm in a seed?

It stores reserve food for the early development of the embryo.

What is cephalisation?

The concentration of nerve cells at the anterior (head) end of a bilaterally symmetrical animal's body, leading to a central nervous system.

Distinguish between diploblastic and triploblastic animals.

Diploblastic animals have two germ layers (ectoderm and endoderm), while triploblastic animals have three germ layers (ectoderm, endoderm, and mesoderm).

What is the biological importance of a coelom?

It separates the digestive tract from the body wall, acts as a hydrostatic skeleton, provides space for complex organs to develop, and serves as a transport medium.

What is the word equation for photosynthesis?

$$\text{CO}_2 + \text{H}_2\text{O} + \text{Radiant energy} \xrightarrow[\text{Enzymes}]{\text{Chlorophyll}} \text{Glucose} + \text{O}_2$$

Where do the Light and Dark phases of photosynthesis occur within the chloroplast?

The light phase occurs in the grana, and the dark phase occurs in the stroma.

At what temperature do plants photosynthesise optimally?

$25^{\circ}C$.

Define the nutritional process of assimilation.

The process where cells absorb nutrients from the blood and use them to build new cell structures and compounds.

What is the human dental formula?

$$\frac{2. 1. 2. 3}{2. 1. 2. 3}$$

What are the two cell types found in the pancreas?

Normal pancreatic cells (secreting pancreatic juice) and Islets of Langerhans (secreting insulin and glucagon).

Where is bile produced and where is it stored?

Bile is produced in the liver and stored in the gall bladder.

Which hormone is secreted by the beta ($\beta$) cells of the islets of Langerhans to reduce blood sugar?

Insulin.

What are the three stages of aerobic cellular respiration?

Glycolysis, Kreb's cycle, and Oxidative phosphorylation.

Where does glycolysis take place?

In the cytosol (cytoplasm) outside the mitochondrion.

What is the final hydrogen acceptor in oxidative phosphorylation?

Oxygen ($\text{O}_2$).

What is the accumulation of oxygen needed to convert lactic acid back to pyruvic acid called?

Oxygen debt.

Name five requirements for an effective gaseous exchange surface.

It must be large, thin, moist, have a transport system, and be well-protected.

How many lobes are found in the right and left human lungs?

The right lung consists of $3$ lobes, and the left lung has $2$ lobes.

Explain the role of the epiglottis.

A thin, leaf-shaped cartilage structure that closes the glottis during swallowing to prevent food from entering the trachea.

What molecule is formed when oxygen combines with haemoglobin in red blood cells?

Oxyhaemoglobin.

What is tidal volume?

The amount of air that is breathed in and out during normal breathing.

Define excretion.

The removal of metabolic wastes from the body.

What are the functional units of the kidney?

Nephrons.

What two parts make up the Malpighian body?

The Bowman’s capsule and the Glomerulus.

Which hormone regulates the water content of the blood (osmoregulation)?

$ADH$ (anti-diuretic hormone).

What formula is used in the mark-recapture technique for population sizing?

$$P = \frac{m \times s}{t}$$

What is eutrophication?

The addition of high levels of nutrients (specifically nitrogen and phosphorus) to water, leading to algae blooms and oxygen depletion.