key concept in biology Flashcards
What is the basic unit of life?
Cell
True or False: All living organisms are made up of cells.
True
Fill in the blank: The process by which plants convert sunlight into energy is called _______.
Photosynthesis
What is the function of the nucleus in a cell?
To store genetic information and control cell activities.
What are the two main types of cells?
Prokaryotic and Eukaryotic
Multiple Choice: Which of the following is NOT a characteristic of life? A) Growth B) Reproduction C) Inability to adapt D) Response to stimuli
C) Inability to adapt
What is the role of ribosomes in a cell?
To synthesize proteins.
True or False: Mitochondria are known as the powerhouse of the cell.
True
Fill in the blank: The semi-permeable membrane surrounding the cell is called the _______.
Cell membrane
What is the difference between plant and animal cells?
Plant cells have a cell wall and chloroplasts; animal cells do not.
Multiple Choice: Which organelle is responsible for energy production? A) Nucleus B) Ribosome C) Mitochondria D) Golgi apparatus
C) Mitochondria
What is DNA?
Deoxyribonucleic acid, the molecule that carries genetic information.
True or False: Enzymes are a type of lipid.
False
Fill in the blank: The process of converting glucose into energy in the absence of oxygen is called _______.
Anaerobic respiration
What is the function of chloroplasts?
To conduct photosynthesis in plant cells.
Multiple Choice: Which of the following is a product of photosynthesis? A) Carbon dioxide B) Oxygen C) Glucose D) Both B and C
D) Both B and C
What is homeostasis?
The maintenance of stable internal conditions in an organism.
True or False: All enzymes are proteins.
True
Fill in the blank: The basic building blocks of proteins are called _______.
Amino acids
What is the primary function of the cell wall in plant cells?
To provide structure and support.
Multiple Choice: Which type of transport requires energy? A) Diffusion B) Osmosis C) Active transport D) Facilitated diffusion
C) Active transport
What is the role of the Golgi apparatus?
To modify, sort, and package proteins and lipids.
True or False: Bacteria are prokaryotic organisms.
True
Fill in the blank: The fluid inside the cell is called _______.
Cytoplasm
What is the purpose of mitosis?
To produce two identical daughter cells for growth and repair.
Multiple Choice: Which phase of the cell cycle involves cell growth? A) S phase B) G1 phase C) M phase D) G2 phase
B) G1 phase
What is the role of DNA polymerase?
To synthesize new DNA strands during replication.
True or False: Osmosis is the movement of solutes across a membrane.
False
Fill in the blank: The basic unit of heredity is called a _______.
Gene
What is the main difference between aerobic and anaerobic respiration?
Aerobic respiration requires oxygen; anaerobic does not.
Multiple Choice: Which macromolecule is primarily responsible for storing genetic information? A) Carbohydrates B) Proteins C) Nucleic acids D) Lipids
C) Nucleic acids
What is the primary role of the rough endoplasmic reticulum?
To synthesize and package proteins.
True or False: Lipids are soluble in water.
False
Fill in the blank: The process of cell division that reduces the chromosome number by half is called _______.
Meiosis
What is a mutation?
A change in the DNA sequence.
Multiple Choice: Which of the following is a function of proteins? A) Energy storage B) Catalyzing reactions C) Structural support D) All of the above
D) All of the above
What is the role of the smooth endoplasmic reticulum?
To synthesize lipids and detoxify certain chemicals.
True or False: The mitochondria have their own DNA.
True
Fill in the blank: The process by which cells produce ATP is known as _______.
Cellular respiration
What is the function of the plasma membrane?
To regulate the movement of substances in and out of the cell.
Multiple Choice: Which structure is responsible for protein synthesis? A) Nucleus B) Ribosome C) Lysosome D) Golgi apparatus
B) Ribosome
What is the primary component of the cell membrane?
Phospholipids
True or False: All cells have a nucleus.
False
Fill in the blank: The genetic material found in viruses is either _______ or _______.
DNA; RNA
What is the role of lysosomes?
To digest and break down waste materials and cellular debris.
Multiple Choice: Which process involves the movement of water across a semipermeable membrane? A) Diffusion B) Filtration C) Osmosis D) Active transport
C) Osmosis
What is the primary function of the cytoskeleton?
To provide structural support and shape to the cell.
True or False: Chloroplasts are found in both plant and animal cells.
False
Fill in the blank: The organelle responsible for packaging and distributing proteins is the _______.
Golgi apparatus
What is the purpose of cellular respiration?
To convert biochemical energy from nutrients into ATP.
Multiple Choice: Which of the following is a type of passive transport? A) Endocytosis B) Exocytosis C) Diffusion D) Active transport
C) Diffusion
What is the role of the cell membrane in homeostasis?
It regulates what enters and leaves the cell to maintain stable internal conditions.
True or False: The endoplasmic reticulum is involved in protein and lipid synthesis.
True
Fill in the blank: The process of converting mRNA into a protein is called _______.
Translation
What is the main purpose of meiosis?
To produce gametes for sexual reproduction.
Multiple Choice: Which type of RNA carries amino acids to the ribosome? A) mRNA B) rRNA C) tRNA D) sRNA
C) tRNA
What is a phenotype?
The observable characteristics of an organism.
True or False: A genotype refers to the physical appearance of an organism.
False
Fill in the blank: The law of _______ states that alleles segregate independently during gamete formation.
Segregation
What is a dominant allele?
An allele that expresses its trait even in the presence of a recessive allele.
Multiple Choice: Which of the following determines the sex of an individual in humans? A) X and Y chromosomes B) Autosomes C) Mitochondrial DNA D) None of the above
A) X and Y chromosomes
What are enzymes?
Enzymes are biological catalysts that speed up chemical reactions in living organisms.
True or False: Enzymes are consumed in the reactions they catalyze.
False
What is the active site of an enzyme?
The active site is the region on the enzyme where substrate molecules bind and undergo a chemical reaction.
Fill in the blank: Enzymes are made up of _____.
proteins
What is the role of substrates in enzyme activity?
Substrates are the reactants that enzymes act upon to form products.
Which factor does NOT affect enzyme activity?
The color of the enzyme
What term describes the maximum rate of an enzyme-catalyzed reaction?
Vmax
True or False: Enzymes can work in both forward and reverse reactions.
True
What is enzyme specificity?
Enzyme specificity refers to the ability of an enzyme to choose exact substrates from a group of similar chemical molecules.
How does temperature affect enzyme activity?
Increased temperature generally increases enzyme activity up to a certain point, after which the enzyme may denature.
What is denaturation in terms of enzymes?
Denaturation is the process in which an enzyme loses its functional shape due to factors like extreme temperature or pH.
Fill in the blank: The pH level can affect enzyme activity, with each enzyme having an optimal _____ range.
pH
What are coenzymes?
Coenzymes are organic molecules that assist enzymes in catalyzing reactions.
Multiple Choice: Which of the following is a factor that can affect enzyme activity? A) Temperature B) Pressure C) Color D) All of the above
A) Temperature
What is the enzyme-substrate complex?
The enzyme-substrate complex is the intermediate formed when a substrate binds to an enzyme’s active site.
True or False: Enzymes can only catalyze one type of reaction.
True
Fill in the blank: The process by which an enzyme binds to its substrate is called _____ binding.
substrate
What is the effect of concentration on enzyme activity?
Increasing substrate concentration generally increases enzyme activity until the enzyme becomes saturated.
What are inhibitors?
Inhibitors are substances that decrease enzyme activity.
Fill in the blank: Competitive inhibitors bind to the _____ site of an enzyme.
active
What is non-competitive inhibition?
Non-competitive inhibition occurs when an inhibitor binds to an enzyme at a site other than the active site.
Multiple Choice: What is the primary function of enzymes? A) To store energy B) To catalyze reactions C) To transport molecules D) To provide structure
B) To catalyze reactions
What is the term for the energy required to start a chemical reaction?
Activation energy
True or False: All enzymes are proteins.
True
What is the lock and key model?
The lock and key model describes how enzymes and substrates fit together precisely, like a key fits into a lock.
Fill in the blank: The _____ model is a modification of the lock and key model, suggesting enzymes can change shape.
induced fit
What effect does increased temperature have on enzyme activity, up to a certain point?
It generally increases enzyme activity.
Fill in the blank: Enzymes are usually named after the _____ they act on.
substrates
What is the function of digestive enzymes?
Digestive enzymes break down food into smaller molecules that can be absorbed by the body.
Multiple Choice: Which of the following is NOT an enzyme? A) Amylase B) Lipase C) Glucose D) Protease
C) Glucose
What happens to an enzyme when it is denatured?
It loses its shape and, consequently, its ability to function.
What role do enzymes play in metabolic pathways?
Enzymes catalyze each step of metabolic pathways, facilitating the conversion of substrates to products.
Fill in the blank: Enzymes lower the _____ energy of a reaction.
activation
What is the significance of enzyme concentration in reactions?
Higher enzyme concentration generally increases the rate of reaction, provided there is enough substrate.
True or False: Enzymes can function at any pH level.
False
What is the primary source of energy for enzyme-catalyzed reactions?
The energy stored in the chemical bonds of substrates.
Fill in the blank: Enzymes are sensitive to changes in _____ and temperature.
pH
What is a substrate’s role in an enzymatic reaction?
The substrate is the molecule upon which an enzyme acts.
Multiple Choice: Which enzyme breaks down proteins? A) Amylase B) Lipase C) Protease D) Cellulase
C) Protease
What is the difference between competitive and non-competitive inhibitors?
Competitive inhibitors bind to the active site, while non-competitive inhibitors bind to another site, affecting the enzyme’s function.
Fill in the blank: The process of enzyme regeneration occurs after the _____ is released.
product
What is the primary purpose of testing food in GCSE biology?
To identify the presence of specific nutrients and substances in food.
True or False: The Benedict’s test is used to test for the presence of proteins.
False
Fill in the blank: The ______ test is used to detect reducing sugars in food.
Benedict’s
What color change indicates a positive result in the iodine test for starch?
Blue-black
Which reagent is used to test for proteins in food?
Biuret reagent
Multiple Choice: Which of the following tests is used for lipids?
A) Benedict’s test
B) Iodine test
C) Emulsion test
D) Biuret test
C) Emulsion test
What is the expected result of a positive Biuret test?
A color change to purple
True or False: The emulsion test for lipids involves adding water.
False
What is the main component tested for using the iodine test?
Starch
Which test would you use to identify if a food sample contains glucose?
Benedict’s test
What is diffusion?
The movement of particles from an area of higher concentration to an area of lower concentration.
True or False: Diffusion requires energy.
False
Fill in the blank: Osmosis is the diffusion of ______ through a semi-permeable membrane.
water
What type of transport requires energy?
Active transport
What is the main difference between diffusion and osmosis?
Diffusion involves all types of particles, while osmosis specifically involves water.
True or False: Active transport moves substances against their concentration gradient.
True
What is a semi-permeable membrane?
A membrane that allows certain molecules to pass through while blocking others.
Multiple Choice: Which process does NOT require cellular energy? A) Active transport B) Diffusion C) Endocytosis
B) Diffusion
What is the role of ATP in active transport?
ATP provides the energy needed to move substances against their concentration gradient.
Fill in the blank: The concentration gradient is the difference in the concentration of a substance between ______.
two areas
What is facilitated diffusion?
The process of diffusion that occurs with the help of a transport protein.
True or False: Osmosis can occur in any type of solution.
False
What happens to a plant cell in a hypertonic solution?
It loses water and becomes plasmolyzed.
Multiple Choice: Which of the following is an example of active transport? A) Glucose transport B) Oxygen diffusion C) Water osmosis
A) Glucose transport
What is the process of moving large particles into a cell called?
Endocytosis
Fill in the blank: In a hypotonic solution, a cell will ______.
swell
What is the primary function of osmosis in cells?
To maintain cell turgor and balance water content.
True or False: Diffusion can occur in solids, liquids, and gases.
True
What is the main factor that affects the rate of diffusion?
Temperature
Multiple Choice: Which of the following is NOT a factor affecting osmosis? A) Temperature B) Concentration gradient C) Size of the solute
C) Size of the solute
What is exocytosis?
The process of expelling materials from a cell.
Fill in the blank: Active transport often involves ______ proteins.
carrier
What is the effect of a cell being placed in a isotonic solution?
There is no net movement of water; the cell maintains its shape.
True or False: Osmosis is a type of passive transport.
True
What happens to animal cells in a hypertonic solution?
They shrivel and may die.
Multiple Choice: Which process requires a transport protein? A) Simple diffusion B) Osmosis C) Facilitated diffusion
C) Facilitated diffusion
What is meant by ‘dynamic equilibrium’ in the context of diffusion?
When the concentration of particles is equal in two areas, resulting in no net movement.
Fill in the blank: The direction of water movement during osmosis is determined by the ______ of solutes.
concentration
What is the significance of the sodium-potassium pump?
It is a key example of active transport that regulates ion concentration in cells.
Fill in the blank: In osmosis, water moves from an area of ______ solute concentration to an area of ______ solute concentration.
low; high
What does it mean for a solution to be hypertonic?
It has a higher concentration of solutes compared to another solution.
