Biology (IGCSE) All Subjects Flashcards
What is the most accurate system of classification?
A - using anatomy
B - using DNA base sequence
C - using morphology
D - using a pedigree chart
B - Using base sequence.
Which part of a plant cell controls the movement of substances into and out of the cell?
Cell membrane
How do carbon dioxide and oxygen move into and out of the mesophyll cell?
A - Active transport
B - Diffusion
C - Respiration
D - Transpiration
B - Diffusion
When testing for glucose, using the Benedict’s solution what color will the solution turn if glucose is present?
What color will the solution turn if glucose is not present?
A - present Blue/black absent Yellow
B - present Purple absent Blue
C - present Brick red/orange absent Blue
C - If glucose is present the solution will turn a Brick red/orange, if absent it will turn blue.
When testing for starch, using an Iodine solution what color will the solution turn if starch is present?
What color will the solution turn if starch is not present?
A - present Blue/black absent stay Yellow
B - present Purple absent Blue
C - present Brick red/orange absent Blue
A - if starch is present the solution will turn a Blue/black color, however if absent it will stay yellow
When testing for proteins, using the Biuret’s solution what color will the solution turn if proteins is present?
What color will the solution turn if proteins is not present?
A - present Blue/black absent Yellow
B - present Purple absent Blue
C - present Brick red/orange absent Blue
B - if proteins are present the solution will turn Purple, if absent it will turn Blue
Which structure produces Lipase?
The pancreas
What is produced by anaerobic respiration in mammals?
A - Alcohol + carbon dioxide
B - Alcohol + oxygen
C - Lactic acid + carbon dioxide
D- Lactic acid
D - Lactic acid
Where is urea produced?
A - Liver
B - Kidneys
C - Pancreas
D - Bladder
A - Liver
Where is urea stored?
A - Liver
B - Kidneys
C - Pancreas
D - Bladder
D - Bladder
Where is urea excreted?
A - Liver
B - Kidneys
C - Pancreas
D - Bladder
B - Kidneys
If two animals have an identical sequence of amino acids in one of the proteins found in their cells what does this indicate about these animals?
They share a recent ancestor
Protoplasts are plant cells that have had their cell wall removed.
What happens if plant protoplasts are placed in distilled water?
A - They get larger and become turgid
B - They get larger and burst
B - They get larger and burst
What is the source in a plant.
A source is any part of the plant that produces or releases sugars, usually through photosynthesis. The main source is the leaves, where sugars are made and then transported to other parts of the plant via the phloem. Other sources can include storage organs (e.g., tubers) during periods of growth when they release stored sugars.
What is a sink in a plant.
A sink is any part of the plant that uses or stores sugars for growth, energy, or storage. Common sinks include roots, developing fruits, seeds, and growing shoots. These areas receive sugars from the source via the phloem to support functions such as growth, energy storage, and reproduction.
Why do organisms that share a more recent common ancestor have more similar DNA sequences?
Organisms with a recent common ancestor have more similar DNA because they have had less time for mutations to accumulate. Over time, DNA sequences change due to mutations, so species that diverged long ago will have more differences.
What are the functions of cartilage in the gas exchange system?
Cartilage in the gas exchange system serves two main functions:
- Support – It helps keep the airways (trachea and bronchi) open, preventing collapse during breathing.
- Protection – It protects the delicate tissues of the airways from damage while allowing flexibility for movement during breathing.
What enzymes break down starch, fat, and protein, and what are their products?
- Starch:
Enzyme: Amylase
Products: Maltose (a disaccharide)
- Fat:
Enzyme: Lipase
Products: Fatty acids and glycerol
- Protein:
Enzyme: Protease (e.g., Pepsin, Trypsin)
Products: Amino acids
What is the function of the endoplasmic reticulum (ER)?
The endoplasmic reticulum (ER) is an organelle that plays a key role in protein and lipid synthesis:
- Rough ER – Covered with ribosomes; helps in the synthesis and transport of proteins.
- Smooth ER – Lacks ribosomes; involved in lipid synthesis and detoxification of harmful substances.
What are the main parts of the human gas exchange system?
The system includes the trachea, bronchi, bronchioles, alveoli, lungs, and diaphragm.
How are alveoli adapted for efficient gas exchange?
Alveoli have a large surface area, thin walls (one-cell thick), and are moist for efficient gas diffusion, they also have a rich blood supply.
How does diffusion help in gas exchange in the lungs?
Oxygen diffuses from alveoli into blood (high to low concentration), and carbon dioxide diffuses from blood to alveoli to be exhaled.
What happens during inhalation and exhalation?
Inhalation: Diaphragm contracts, ribcage moves up/out, volume increases, pressure decreases, air enters.Exhalation: Diaphragm relaxes, ribcage moves down/in, volume decreases, pressure increases, air exits.
How does exercise affect breathing rate and depth?
Exercise increases breathing rate and depth to supply more oxygen for respiration and remove CO2 faster.
How does the composition of inhaled and exhaled air differ?
Inhaled air: 21% oxygen, 0.04% CO2, 78% nitrogen.Exhaled air: 16% oxygen, 4% CO2, 78% nitrogen. More CO2 and less oxygen in exhaled air.
What are the effects of smoking on the lungs?
Smoking damages alveoli, reduces surface area for gas exchange, causes tar buildup, increases mucus, and can lead to lung diseases like emphysema and lung cancer.
What is the function of the lymphatic system?
The lymphatic system helps in:
- Returning excess tissue fluid to the bloodstream
- Transporting white blood cells for immunity
- Absorbing fats from the small intestine
What is lymph?
Lymph is a clear fluid that contains:
- White blood cells (especially lymphocytes)
- Less protein than blood plasma
- Fats absorbed from the small intestine
How does the lymphatic system help in immunity?
- Lymph nodes contain lymphocytes that help fight infections.
- Lymph filters out bacteria and foreign particles before returning to the blood.
How does lymph move in the lymphatic system?
- No pump (unlike the circulatory system).
- Moves by the contraction of muscles and one-way valves prevent backflow.
How does the lymphatic system relate to the circulatory system?
- Excess tissue fluid drains into lymph vessels.
- Lymph returns to the bloodstream near the subclavian vein in the chest.
What are lymph nodes and their function?
- Small structures that filter bacteria and harmful substances from lymph.
- Contain white blood cells (lymphocytes) that attack infections.
How does the lymphatic system help in digestion?
- Lacteals (lymph capillaries in villi of the small intestine) absorb fatty acids and glycerol.
- Fats travel through the lymph before entering the bloodstream.
What happens if the lymphatic system fails?
- Edema: Swelling due to fluid buildup in tissues.
- Weakened immune response: Infections spread more easily.
- Nutrient absorption issues: Fat digestion problems.
