Biology A2 Lecture Notes Review

Practice flashcards based on key concepts, definitions, and details from the provided lecture notes in Biology A2.

What is respiration defined as?

The enzymatic release of energy from organic compounds in living cells.

What is glycolysis?

The splitting (lysis) of glucose; the first stage in aerobic respiration.

What does NAD stand for?

Nicotinamide adenine dinucleotide; a hydrogen carrier used in respiration.

What is the function of ATP synthase?

It catalyses the phosphorylation of ADP to ATP.

What is chemiosmosis?

The synthesis of ATP using energy released by the movement of hydrogen ions down their concentration gradient across a membrane.

Define aerobic respiration.

The process of breaking down glucose in the presence of oxygen to produce ATP.

What occurs during the Krebs cycle?

A cycle of reactions in aerobic respiration in which hydrogens pass to hydrogen carriers for subsequent ATP synthesis.

What is oxidative phosphorylation?

The synthesis of ATP from ADP and inorganic phosphate (Pi) using energy from oxidation reactions.

What is anaerobic respiration?

A form of respiration that occurs without oxygen.

Explain the term 'respiratory quotient (RQ)'.

The ratio of the volume of carbon dioxide produced to the volume of oxygen consumed.

What are the stages of aerobic respiration?

1. Glycolysis, 2. Link reaction, 3. Krebs cycle, 4. Oxidative phosphorylation.

What is the role of coenzyme A (CoA)?

It supplies the acetyl group required for the link reaction.

How does ATP function as an energy currency?

It is used in all organisms for various biochemical reactions and can be reused many times.

What is the significance of the electron transport chain?

It facilitates the transfer of electrons through a series of carriers, driving ATP synthesis.

What effect does the lack of oxygen have on respiration?

It halts the electron transport chain, ceasing ATP production via oxidative phosphorylation.

What is the primary ecological role of aerenchyma in plants?

It provides air spaces for gas exchange, aiding in respiration and flotation.

Define homeostasis in a biological context.

The process of maintaining a stable internal environment in an organism.

What is negative feedback in homeostasis?

A process where a change in a system triggers a response that counteracts that change.

What are the Islets of Langerhans?

Clusters of cells in the pancreas that secrete insulin and glucagon.

What is the significance of gene therapy?

It is used to treat genetic disorders by introducing, removing, or altering genetic material within a patient's cells.

Describe genetic screening.

The process of testing for genetic disorders before the onset of symptoms.

What is the role of a promoter in genetics?

A sequence of DNA that facilitates the initiation of transcription of a particular gene.

How do both the endocrine and nervous systems coordinate responses within the body?

The endocrine system uses hormones for slower, longer-lasting responses, while the nervous system uses rapid electrical impulses for immediate responses.

What is stability in allele frequencies?

The consistent rates of alleles in a population over generations, typically maintained by factors such as Hardy-Weinberg equilibrium.

What is respiration defined as?

The enzymatic release of energy from organic compounds in living cells.

What is glycolysis?

The splitting (lysis) of glucose; the first stage in aerobic respiration.

What does NAD stand for?

Nicotinamide adenine dinucleotide; a hydrogen carrier used in respiration.

What is the function of ATP synthase?

It catalyses the phosphorylation of ADP to ATP.

What is chemiosmosis?

The synthesis of ATP using energy released by the movement of hydrogen ions down their concentration gradient across a membrane.

Define aerobic respiration.

The process of breaking down glucose in the presence of oxygen to produce ATP.

What occurs during the Krebs cycle?

A cycle of reactions in aerobic respiration in which hydrogens pass to hydrogen carriers for subsequent ATP synthesis.

What is oxidative phosphorylation?

The synthesis of ATP from ADP and inorganic phosphate (Pi) using energy from oxidation reactions.

What is anaerobic respiration?

A form of respiration that occurs without oxygen.

Explain the term 'respiratory quotient (RQ)'.

The ratio of the volume of carbon dioxide produced to the volume of oxygen consumed.

What are the stages of aerobic respiration?

1. Glycolysis, 2. Link reaction, 3. Krebs cycle, 4. Oxidative phosphorylation.

What is the role of coenzyme A (CoA)?

It supplies the acetyl group required for the link reaction.

How does ATP function as an energy currency?

It is used in all organisms for various biochemical reactions and can be reused many times.

What is the significance of the electron transport chain?

It facilitates the transfer of electrons through a series of carriers, driving ATP synthesis.

What effect does the lack of oxygen have on respiration?

It halts the electron transport chain, ceasing ATP production via oxidative phosphorylation.

What is the primary ecological role of aerenchyma in plants?

It provides air spaces for gas exchange, aiding in respiration and flotation.

Define homeostasis in a biological context.

The process of maintaining a stable internal environment in an organism.

What is negative feedback in homeostasis?

A process where a change in a system triggers a response that counteracts that change.

What are the Islets of Langerhans?

Clusters of cells in the pancreas that secrete insulin and glucagon.

What is the significance of gene therapy?

It is used to treat genetic disorders by introducing, removing, or altering genetic material within a patient's cells.

Describe genetic screening.

The process of testing for genetic disorders before the onset of symptoms.

What is the role of a promoter in genetics?

A sequence of DNA that facilitates the initiation of transcription of a particular gene.

How do both the endocrine and nervous systems coordinate responses within the body?

The endocrine system uses hormones for slower, longer-lasting responses, while the nervous system uses rapid electrical impulses for immediate responses.

What is stability in allele frequencies?

The consistent rates of alleles in a population over generations, typically maintained by factors such as Hardy-Weinberg equilibrium.

What is the function of mitochondria in cells?

The powerhouse of the cell; it produces ATP through respiration.

What are the end products of glycolysis?

Two molecules of pyruvate, two molecules of ATP, and two molecules of NADH.

What is the purpose of the link reaction in respiration?

To convert pyruvate into acetyl CoA and produce NADH.

Describe the role of oxygen in aerobic respiration.

Oxygen serves as the final electron acceptor in the electron transport chain.

What is fermentation?

An anaerobic process by which ATP is produced from glucose without oxygen.

How does temperature affect the rate of respiration?

In general, higher temperatures increase the rate of respiration, but extreme temperatures can be detrimental.

What are the benefits of anaerobic respiration?

It allows for ATP production in the absence of oxygen, though less efficiently than aerobic respiration.

Define the term 'bioenergetics'.

The study of the flow and transformation of energy in and between living systems.

What is lactate fermentation?

A type of anaerobic respiration that occurs in muscle cells and some bacteria, producing lactate from pyruvate.

What occurs during oxidative stress?

An imbalance between free radicals and antioxidants in the body, leading to damage.

What are the three main stages of photosynthesis?

1. Light-dependent reactions, 2. Light-independent reactions (Calvin cycle), 3. Carbon fixation.

What is the role of chlorophyll in photosynthesis?

Chlorophyll absorbs light energy, primarily from the blue and red wavelengths.

Define the light-harvesting complex in plants.

A collection of proteins and pigments that capture light energy for photosynthesis.

What are thylakoids?

Membrane-bound compartments inside chloroplasts that are the site of the light-dependent reactions of photosynthesis.

What is the significance of the Calvin cycle?

It converts carbon dioxide and other compounds into glucose, using ATP and NADPH produced in the light-dependent reactions.

How does the structure of a leaf facilitate photosynthesis?

Leaves have large surface areas, thin structures, and contain chloroplasts to optimize light absorption.

What is a heterotroph?

An organism that obtains its food by consuming other organisms.

What is an autotroph?

An organism that produces its own food, typically through photosynthesis or chemosynthesis.

How do enzymes affect biochemical reactions?

Enzymes act as catalysts, speeding up reactions by lowering the activation energy.

What factors affect enzyme activity?

Temperature, pH, substrate concentration, and the presence of inhibitors or activators.

What is allosteric regulation?

The regulation of an enzyme's activity through the binding of molecules at sites other than the active site.

Define substrate-level phosphorylation.

The direct synthesis of ATP from ADP and a phosphate group during specific reactions.

What are the main products of the Krebs cycle?

Energy carriers: NADH, FADH2, ATP, and CO2 as a waste product.

How do cyclic and non-cyclic photophosphorylation differ?

Cyclic photophosphorylation involves only PSI, producing ATP, whereas non-cyclic involves both PSI and PSII, producing both ATP and NADPH.

What is the role of ATP in metabolic processes?

ATP acts as the energy currency of the cell, powering various cellular functions.

What is homeostatic regulation?

The mechanisms that maintain balance in biological systems despite external changes.

How is glucose transported in the body?

Glucose is transported in the bloodstream to cells, where it is used for energy or stored as glycogen.

What are the effects of exercise on cellular respiration?

Exercise increases the demand for energy, enhancing the rate of cellular respiration.

What role does insulin play in metabolism?

Insulin facilitates the uptake of glucose by cells and regulates carbohydrate metabolism.

What is the endocrine system's function?

To secrete hormones that regulate various bodily functions, including metabolism and growth.

Describe the function of glucagon.

Glucagon raises blood sugar levels by promoting glycogen breakdown and glucose release from the liver.

How does the body maintain blood glucose levels?

By balancing the actions of insulin and glucagon based on blood glucose concentration.

What is genetic drift?

Random changes in allele frequencies in a population, typically significant in small populations.

What is gene flow?

The transfer of alleles or genes from one population to another through migration.

What is the difference between dominant and recessive alleles?

Dominant alleles express their trait even if only one copy is present, while recessive alleles require two copies to express the trait.

Define mutation.

A change in the DNA sequence that can lead to genetic diversity.

What is the result of a point mutation?

A change in a single nucleotide in the DNA sequence, potentially affecting protein function.

What is polygenic inheritance?

Inheritance of traits that are determined by multiple genes.

How does environmental factors influence genetic expression?

External conditions can affect how genes are expressed, impacting an organism's phenotype.

What is the significance of the Hardy-Weinberg principle?

It provides a framework for understanding genetic variation in a population under ideal conditions.

What are the conditions for Hardy-Weinberg equilibrium?

1. No mutations, 2. No gene flow, 3. Large population size, 4. No natural selection, 5. Random mating.

What is the role of ribosomes in protein synthesis?

Ribosomes are the sites where translation occurs, synthesizing proteins from amino acids.

Describe the process of transcription.

The synthesis of RNA from a DNA template.

What is the significance of the genetic code?

It determines how sequences of nucleotides correspond to specific amino acids in proteins.

What are exons and introns?

Exons are coding segments of RNA, whereas introns are non-coding segments that are removed during RNA processing.

What is the role of tRNA in translation?

tRNA brings the appropriate amino acids to the ribosome based on the mRNA codon sequence.

What is the structure of DNA?

A double helix formed by two strands of nucleotides complementary to each other.

What is a phenotype?

The observable physical or biochemical characteristics of an organism.

How does natural selection contribute to evolution?

Natural selection favors individuals with advantageous traits, leading to gradual changes in a population over time.

What is the significance of (K) and (r) strategies in evolution?

K-strategists are species that invest heavily in offspring care, while r-strategists reproduce quickly with minimal care.

What is speciation?

The process by which new species arise from existing ones.

How does isolation contribute to speciation?

Geographic or reproductive isolation can prevent gene flow, leading to the divergence of populations.