JMSS Science test revision

What is the nucleus and its function?

The nucleus is the organelle that contains the cell's DNA and is responsible for regulating gene expression and maintaining the integrity of genes.

What is the role of mitochondria?

Mitochondria are the powerhouse of the cell, producing ATP through cellular respiration.

What is a cell wall?

The cell wall is a rigid outer layer found in plant cells, providing structural support and protection.

What is a Punnett square?

A Punnett square is a diagram used to predict the genetic makeup of offspring from parental genotypes.

What are dominant and recessive traits?

Dominant traits are expressed when at least one dominant allele is present; recessive traits are expressed only when two recessive alleles are present.

What is natural selection?

Natural selection is the process through which individuals with favorable traits are more likely to survive and reproduce.

What is the structure of DNA?

DNA is composed of two strands forming a double helix, made up of nucleotides containing a sugar, phosphate group, and nitrogenous base.

How do the circulatory, respiratory, and nervous systems interact to maintain homeostasis?

These systems work together to regulate blood flow, oxygen intake, and response to stimuli, maintaining stable internal conditions.

What are protons, neutrons, and electrons?

Protons are positively charged particles in the nucleus, neutrons are neutral particles also in the nucleus, and electrons are negatively charged particles orbiting the nucleus.

How do you read the periodic table?

The periodic table organizes elements by atomic number, with rows indicating periods and columns indicating groups with similar properties.

What are reactants and products in a chemical reaction?

Reactants are substances that undergo a chemical change, while products are the substances formed as a result of that change.

How do you balance a chemical equation?

Balancing a chemical equation involves ensuring the number of atoms for each element is the same on both sides of the equation.

What are signs of chemical change?

Signs include color change, temperature change, gas production, and precipitate formation.

What factors affect reaction rates?

Factors include temperature, concentration, surface area, and the presence of catalysts.

What is the pH scale?

The pH scale measures the acidity or basicity of a solution, ranging from 0 (acidic) to 14 (basic) with 7 being neutral.

What are forms of energy?

Forms of energy include kinetic energy (energy of motion) and potential energy (stored energy).

How does heat transfer occur?

Heat can be transferred through conduction (direct contact), convection (fluid movement), and radiation (electromagnetic waves).

What is the difference between speed, velocity, and acceleration?

Speed is the rate of motion, velocity is speed with direction, and acceleration is the change in velocity over time.

What are Newton's laws of motion?

1) An object in motion stays in motion unless acted upon by an external force. 2) Force equals mass times acceleration. 3) For every action, there is an equal and opposite reaction.

How do you interpret distance-time graphs?

The slope of the line represents speed; a steeper slope indicates higher speed, and a flat line indicates no motion.

What is the electromagnetic spectrum?

The electromagnetic spectrum is the range of all types of electromagnetic radiation, from radio waves to gamma rays.

What is the behavior of light and sound?

Light travels in waves and can be reflected, refracted, or absorbed. Sound travels as waves through mediums and can also reflect and refract.

What is the rock cycle?

The rock cycle is the continuous process of rock formation and transformation through igneous, sedimentary, and metamorphic processes.

What are plate tectonics?

Plate tectonics is the theory explaining the movement of Earth's lithospheric plates, resulting in geological activity like earthquakes and volcanic eruptions.

What are geological boundaries?

Geological boundaries are the edges where tectonic plates interact, including divergent, convergent, and transform boundaries.

What is the lifecycle of stars?

The lifecycle of stars includes stages such as nebula, main sequence, red giant, and supernova, eventually leading to white dwarfs or black holes.

What are the key components of the solar system?

Key components include the sun, planets, moons, asteroids, comets, and meteoroids.

What is the universe?

The universe encompasses all space, time, matter, and energy, including galaxies, stars, planets, and cosmic phenomena.

What is the function of ribosomes?

Ribosomes are the sites of protein synthesis in cells, translating messenger RNA into polypeptides.

What are lysosomes?

Lysosomes are organelles that contain digestive enzymes to break down waste materials and cellular debris.

What is the endoplasmic reticulum?

The endoplasmic reticulum (ER) is a network of membranes involved in protein and lipid synthesis; it includes rough ER (with ribosomes) and smooth ER (without ribosomes).

What is the golgi apparatus?

The golgi apparatus processes, sorts, and packages proteins and lipids for secretion or use within the cell.

How do two alleles interact in inheritance?

Two alleles can interact in various ways, such as complete dominance, incomplete dominance, or co-dominance, affecting the phenotype of an organism.

What is genetic drift?

Genetic drift is a mechanism of evolution that leads to changes in allele frequencies in a population due to random sampling effects.

What is the difference between DNA and RNA?

DNA is double-stranded, contains deoxyribose sugar, and uses thymine (T), whereas RNA is single-stranded, contains ribose sugar, and uses uracil (U) instead of thymine.

What is homeostasis?

Homeostasis is the process through which biological systems maintain stability while adjusting to changing external conditions.

How are ions formed?

Ions are formed when atoms gain or lose electrons, resulting in a net electrical charge; cations are positively charged, while anions are negatively charged.

What is atomic mass?

Atomic mass is the weighted average mass of an element's isotopes, measured in atomic mass units (amu).

What is a chemical reaction?

A chemical reaction is a process that involves the transformation of reactants into products through the breaking and forming of chemical bonds.

What are endothermic and exothermic reactions?

Endothermic reactions absorb heat from the surroundings, while exothermic reactions release heat to the surroundings during the reaction.

What is the difference between kinetic and potential energy?

Kinetic energy is the energy of motion, while potential energy is stored energy based on an object's position or state.

What is conduction?

Conduction is the transfer of heat through direct contact between materials, where heat moves from the hotter object to the cooler one.

What is convection?

Convection is the transfer of heat through the movement of fluids (liquids or gases) caused by differences in temperature and density.

What is radiation?

Radiation is the transfer of energy through electromagnetic waves, which can occur in a vacuum without the need for a medium.

What is gravitational potential energy?

Gravitational potential energy is the energy an object possesses due to its height above the ground, given by the formula $PE = mgh$, where $m$ is mass, $g$ is the acceleration due to gravity, and $h$ is height.

What are the types of waves in the electromagnetic spectrum?

The electromagnetic spectrum includes various types of waves, such as radio waves, microwaves, infrared radiation, visible light, ultraviolet rays, X-rays, and gamma rays.

What is the Doppler effect?

The Doppler effect is the change in frequency or wavelength of a wave in relation to an observer moving relative to the wave source.

How does the Earth's rotation affect plate tectonics?

The Earth's rotation affects plate tectonics through the Coriolis effect, which can influence the movement and interaction of tectonic plates over time.

What are metamorphic rocks?

Metamorphic rocks are formed from existing rocks that undergo transformation due to heat, pressure, or chemically active fluids.

What is a black hole?

A black hole is a region of space where the gravitational pull is so strong that nothing, not even light, can escape from it.

What is dark matter?

Dark matter is a type of matter that does not emit light or energy, making it invisible, yet it exerts gravitational forces and is believed to make up a significant portion of the universe's mass.