General Science: Forces, Solutions, Human Systems, and Plant Physiology

Comprehensive practice flashcards covering forces and motion, solutions and mixtures, the human circulatory and respiratory systems, and plant physiology including photosynthesis, transpiration, and respiration.

What is Newton's third law of motion, and how does a book resting on a table illustrate it?

Newton's third law of motion states: "To every action, there is an equal and opposite reaction." When a book rests on a table, the force exerted by the book (equal to its weight) downward on the table is the action, and the table exerts an equal force in the opposite upward direction on the book as the reaction.

What is the Standard International (SI) unit of force and its symbol?

The Standard International (SI) unit of force is the newton, represented by the symbol $\text{N}$.

How do space shuttle engines demonstrate action and reaction forces during launch?

The space shuttle engines push out hot gases downward as an action force, and the hot gases exert an equal and opposite reaction force upward on the shuttle engines, causing the shuttle to lift up.

Why is the mechanical force exerted by a crane when lifting heavy objects classified as a contact force?

It is classified as a contact force because the crane and the heavy object must come into direct physical contact with each other in order to exert the lifting force.

What are non-contact forces, and what are three examples?

Non-contact forces are forces that do not involve physical contact between the objects on which they act, acting instead through the space between them. Three examples are magnetic force, electrostatic force, and gravitational force.

Why does a moving bicycle stop after a rider stops pedaling?

The bicycle stops moving because of frictional force, which is a contact force produced by the physical contact between the tires of the bicycle and the ground.

What causes an object thrown upward to return to the ground?

An object thrown upward returns to the ground due to the Earth's downward pull on the object, which is gravity.

What are two fundamental effects that force can have on an object?

Force can make an object at rest move and can stop a moving object.

What is a binary solution, and how are its two components defined?

A binary solution is a homogeneous mixture prepared by mixing only two substances. Its two components are the solute (the substance that dissolves, present in the smaller quantity, such as sugar in a $5\%$ solution) and the solvent (the substance in which the solute dissolves, forming the bulk of the solution and present in the larger quantity, such as water).

What are the structural and functional differences between arteries and veins?

Arteries are thick-walled vessels with no valves and a narrower lumen that carry blood under high pressure away from the heart. Veins have thinner, less muscular walls with larger lumens and internal valves to prevent backflow, carrying blood under lower, smooth pressure back to the heart.

What is the structural feature and functional role of capillaries in the circulatory system?

Capillaries are tiny, very thin-walled blood vessels that divide from arterioles and provide a large surface area for the exchange of materials between the blood and body tissues.

Why do veins located beneath the skin appear bluish?

Veins appear bluish beneath the skin because they contain deoxygenated blood.

What is the pericardium, and how is the human heart internally divided into chambers?

The pericardium is a thin, double-layered transparent membrane that encloses the heart. Internally, the heart is divided into four chambers: two upper thin-walled chambers called atria (left atrium and right atrium) and two lower thicker-walled chambers called ventricles (left ventricle and right ventricle).

How does blood circulate through the four chambers of the heart during contraction?

The right atrium receives deoxygenated blood from the upper and lower body and pumps it to the right ventricle, which pumps it to the lungs. The left atrium receives oxygenated blood from the lungs and pumps it to the left ventricle, which pumps it to the rest of the body through the aorta.

How does the wall thickness of the left ventricle compare to that of the right ventricle?

The wall of the left ventricle is thicker than the wall of the right ventricle.

How do inhalation, exhalation, and cellular respiration differ?

Inhalation is breathing air into the lungs; exhalation is breathing air out of the lungs; cellular respiration is the chemical reaction of oxygen with food (glucose) inside cells to release energy.

What is transpiration in plants?

Transpiration is the process where excessive water absorbed by roots is conducted to the leaves and lost through evaporation from the aerial parts of the plant, primarily via stomata.

How do photosynthesis and respiration contrast in terms of cellular location and chemical reactants/products?

Photosynthesis occurs in chloroplasts of green plants, algae, and some bacteria, converting $CO_2$ and $H_2O$ into glucose and $O_2$ using light energy. Cellular respiration occurs in the mitochondria of all living cells, using glucose and $O_2$ as reactants to produce $CO_2$, $H_2O$, and usable energy.

Why do plants need nitrogen, and what are the symptoms of nitrogen deficiency?

Plants require nitrogen in the form of nitrates dissolved in soil water to make chlorophyll and amino acids (which form proteins). Nitrogen deficiency turns leaves pale green or yellow and slows the rate of photosynthesis and plant growth.

What is the word equation for cellular respiration?

$$\text{Food (Glucose)} + \text{Oxygen} \rightarrow \text{Carbon dioxide} + \text{Water} + \text{Chemical energy}$$

Why are mitochondria described as the "power house of the cell"?

Mitochondria are called the power house of the cell because they carry out cellular respiration, which is the only continuous process that provides usable energy for living things.

Which specific colors of the light spectrum does chlorophyll absorb for photosynthesis?

Although light consists of seven colors, chlorophyll specifically absorbs blue and red light.

What is the concentration of carbon dioxide in the air, and what is the suitable temperature range for photosynthesis?

Air contains $0.03\% \text{ to } 0.04\%$ carbon dioxide ($CO_2$), and the suitable temperature range for photosynthesis is $25^\circ\text{C} \text{ to } 35^\circ\text{C}$.

How are the palisade mesophyll and spongy mesophyll tissues in a leaf adapted for photosynthesis?

The palisade mesophyll forms a thick layer containing a large number of chloroplasts just beneath the upper epidermis for maximum light absorption. The spongy mesophyll contains maximum air spaces near the lower epidermis to allow carbon dioxide to diffuse easily into cells containing chloroplasts.

What is the word equation for photosynthesis?

$$\text{Carbon dioxide} + \text{Water} + \text{Sunlight energy} \rightarrow \text{Food (Glucose)} + \text{Oxygen}$$

How does the rate of photosynthesis vary across noon, morning/evening, and nighttime?

The rate of photosynthesis is fastest at noon due to high light intensity, slower in the morning and evening because light intensity is reduced, and completely stops at night because there is no sunlight.

What leaf structures are shown in this diagram, and what two physiological states do they illustrate?

The diagram illustrates stomata in leaves, showing an open state ("Stoma open") for gaseous exchange and transpiration, and a closed state ("Stoma closed") to conserve water.