BIO-SCIENCE END OF SEMESTER EXAM

What are cells?

Basic building blocks of all organisms.

What are the two main cell types?

Eukaryotic & Prokaryotic

What are organelles?

Specialised structures within cells that perform specific functions.

What is the Nucleus?

Known as the “Control Centre”

Contains the cells genetic material.

What is the mitochondria’s function?

Energy production: ATP

Fold = cristae

Outer & Inner Membrane = matrix

ATP production by “cellular respiration”

What is the Rough Endoplasmic Reticulum and function?

It makes proteins and modifies them into the right shape.

Ensures proteins are properly folded before sending them off.

What is Smooth Endoplasmic Reticulum and the function?

Makes lipids and steroids

Helps to detoxify harmful substances

Storage and release od calcium ions

What is the function for ribosomes?

Make proteins

Read genetic information and produce the desired protein. (Transcription & translation)

Regulate gene expression

What is the function of the Golgi Apparatus?

Modifies, sorts and packages proteins & lipids in and out of a cell.

Flat stacked membranes = cisternae

Can modify vesicles

What are the functions of the Lysosomes?

Cells digestive systems

Contains digestive enzymes

Cellular defense

Cell signaling & energy metabolism.

What is the function of the Cytoskeleton?

Network of protein filaments

Provide structure, support, shape and organisation of a cell.

Critical role in cell division and transport of organelles, vesicles and other components within a cell.

What is the function of the Cytoplasm?

Supports and facilitates cellular processes + helps maintain cell integrity and chape.

What is the plasma membrane/cell membrane?

Seperates external and internal environment.

Provides structure & protection.

Regulates movement in and out of a cell.

Composed of a phospholipid bilayer

Cell signaling & communication

What is the function of the vacuole for animal and then plant?

In animal cells, function is transportation & storage.

In plant cells, maintaining structure and regulating water balance/pressure.

What is the function of Cilia?

Movement of substances across the surface of the cell or move the cell itself.

What are the 3 organelles unique to plant cells?

1. Chloroplasts

2. Cell wall

3. Plasmodesmata

What is the function of Chloroplasts?

Site of photosynthesis

Energy conversion

Thylakoids, grana and stroma

Produce oxygen

What is the function of the cell wall?

Provides structural support, protection and maintains cell shape.

Rigid structure

Prevents bursting under osmotic pressure

What is the function of the Plasmodesmata?

Small channels between plant cells that allow for direct cytoplasmic exchange and communication.

Why do cells need energy?

To maintain their structure and carry out biochemical reactions.

What is the primary energy used by cells?

ATP: Adenosine Tripphosphate

How is ATP produced overall?

When nutrients (carbohydrates, lipids, proteins) are metabolised.

What is the energy cycle?

Involves energy storage and release within cells.

Cellular respiration

Excess energy stored mainly as glycogen

What are the three main domains of energy supply?

Mechanical Domain

Synthesis Domain

Transport Domain

What is Mechanical Domain?

Actin-Myosin interactions for movement (eg muscule contractions)

What is a Synthesis domain function?

For building macromolecules (proteins, nuclecic acids, lipids)

Requires energy for transportation, translation and replication

What is the function for transport domain?

Active transport against gradients (eg sodium-potassium pump)

Vesicular transport (endocytosis, exocytosis)

What are the three energy types?

1. Kinetic

2. Potential

3. Thermal

What is the function of Kinetic energy?

Energy of motion (depends on mass and velocity)

What is the function for Potential energy?

Stored energy based on position, shape, or condition.

What is the function for thermal energy?

Energy associated with the random motion of particles (temperature).

Examples for Potential energy?

Glucose and other organic molecules store chemical energy in their bonds.

Breaking these bonds releases energy for ATP production

Glycogen stores glucose for later energy needs

What is the full name for ATP?

Adenosine Triphosphate

What is Adenosine Triphosphate?

It is a primary energy currency for cells

How is Adenosine Triphosphate made?

Made via cellular respiration (eg, from glucose)

What is ATP composed of?

Adenine

Ribose

Three phosphate

When does ATP release energy?

When it is hydrolysed

Define Hydrolysis in relation to ATP

A crucial biochemical that releases energy, enabling cellular functions.

What is the process of Hydrolysis?

Water splits the terminal phosphate bond

Energy is released for cellular work

Produces ADP + Pi

When is ATP used?

Immediatley

Where is Glycogen stored for energy?

In liver and muscule

Where are lipids stored for energy?

Triglycerides are stored in adipose tisse

What is the electrochemical gradient?

Created by ion concentration and charge diffrences across a membrane.

What are 3 sources of energy categories?

Organic Molecules (Carbs, lipids, proteins)

Inorganic Molecules (hydrogen sylfide)

Sunlight (photosynthesis)

What are the FOUR levels of the food chain?

Primary producers (Autotrophs)

Primary Consumers (Herbivores)

Secondary Consumers (Carnivores)

Tertiary Consumers (Apex predators)

What are chemical reactions?

Involve breaking/forming of bonds (Reactants — products)

What is Chemical Equilibrium?

Rates of forward reaction and reverse reactions become equal.

What is Exergonic and Endergonic reactions?

Exergonic: release energy (eg glucose breakdown in respiration)

Endergonic: Require energy input (eg protein synthesis)

Define metabolism

Metabolsim involves all biochemical processes necessary for life.

Core functions of Metabolism

Supports growth and reproduction

Facilitaes repair and recovery

Helps organisms adapt and respond to their enviroment.

What are Metabolic processes?

Convert nutrients into energy

Use energy to build and mainatin cellular structures

What are the two types of Metabolism?

Catabolism

Anabolism

What is the function and examplenof Catabolism?

Breaks down molecules to release energy

EG Digestion of food and cellular respiration

What is the function and an example of Anabolism?

Uses energy to construct essential components

EG important for building proteins, DNA and other critcal cell structures

What are 3 reasons Metabolism is important?

Energy Production

Growth & Maintenance

Waste elimination

What are Enzymes?

Proteins that act as biological catalysts

Speed up chemical reactions without being consumed or altered

What is the mechanism of Enzyme action and provide examples?

Lower the activation energy needed fo reactions

Specific to substrates: fir together like lock and key

Digestive enzymes help break down food into nutrients

DNA polymerase synthesizes DNA during cell replication

What are metabolic pathways?

Are a series of connected enzymatic reactions that produce specific products. Each step is catalyzed by a different enzyme

What is the importance of metabolic pathways?

Allow cells to regulate metabolic balance

Efficient conversion of substances into energy, building blocks, or waste products.

What are some examples of metabolic pathways?

Glycolysis: converts glucose into pryuvate, producing ATP

Citric Acid Cycle: Oxidies acetyl-CoA to CO2, generating ATP and electron carriers.

Pathways are controlled by ‘feedback loops’

What is cellular respiration?

A process of which cells convert biochemical energy from nutrients into ATP. It occurs in both prokaryotic and eukaryotic cells

What is the main objective for Cellular Respiration?

To convert the chemical energy found in glucose into chemical energy found in ATP to power cellular activities essential for survival.

What are the 3 stages for cellular respiration.

1. Glycolysis

2. The Citric Acid Cycle

3. Electron Transport Chain

Where does Glycolysis happen? what does it start/end with.

Takes place in the cytoplasm of the cell.

Begins with glucose ends with pryuvate

What are the Key Steps and products involved in Glycolysis?

Involves ten enzyme reactions

Produced 2 ATP molecules per glucose, 2 NADH and 2 pryuvate molecules.

What are some key factors of Glycolysis?

Does not require oxygen as it’s an anaerobic process

First stage in all types of cellular respiration

Where does the Citric Acid/Krebs cycle occur?

Occurs in the mitochondrial matrix

Begins with the oxidation of pyruvate to acetyl-CoA

Key steps & products in the Krebs/Citric Acid cycle?

Cycles through eight major enzymatic steps.

Produces 2 ATP per glucose molecule, multiple NADH and FADH2

What are some key factors of the Citric acid/kreb cycle?

Its the central hub for cellular metabolism

Connects to many other biochemical pathways.

Where does the Electron Transport Chain ETC occur?

Located in the inner membrane of the mitochondria

Electrons from NADH and FADH2 are transferred through a series of protein complexes

What are the key steps involved in the ETC process?

Creates a proton gradient used to produce ATP via chemiosmosis

Produced approx 34 ATP molecules per glucose molecule

What are the key functions of the Electron Transport Chain?

Major site of oxygen consumption and ATP production.

The efficiency of ETC determines cellular energy yeild.

Define Glucose and its function?

A simple sugar with the chemical formula C6H1206.

The primary source of energy for cells is easily absorbed and metabolized by most organisms.

What is the Aerobic Respiration Pathway?

Occurs in the presence of oxygen

Begins with glycolysis in the cytoplasm: it breaks glucose into pyruvate.

Pyruvate enters mitrochondria for the citric acid cycle

Results in efficient ATP production

What is the Anaerobic Respiration Pathway?

Activated when oxygen is scarce.

Anaerobic glycolysis produces lactate in animals, ethanol in yeast

Allows continued ATP generation with less efficiently.

What is the cell cycle?

Is a series of carefully regulated stages that a cell undergoes grow, duplicate its genetic material, and divide into two new cells.

Why is the cell cycle important for DNA?

To ensure DNA is accurately copied and equally distributed, allowing each new cell to function normally.

What are the two main phases of the cell cycle and their function?

Interphase: the cell grows and prepares for division

M Phase: when the cell physically divides

What are the stages of Interphase?

G1 (Gap 1)

S (Synthesis)

G2 (Gap)

What happens during the G1 phase (Interphase)?

• The cell increases in size

• Normal metabolic processes are carried out

• Proteins and organelles required for everyday cellular functions are produced

What happens during the S phase (synthesis/interphase)?

• DNA replication occurs

• Each chromosome is duplicated

• Two identical sister chromatids are formed for every chromosome

• The microtubule organising Centre (MTOC) is also duplicated.

• Accurate DNA replication is essential as many errors introduced at this stage can be passed on to daughter cells

What happens in the G2 (Gap 2) phase of Interphase?

• Final preparation stage before mitosis begins

• The cell continues to grow

• DNA is checked for damage

• Proteins required for chromosome movement and cell division are synthesized

• Only cells that pass these chekcs proceed into mitosis

What does amphiphatic nature mean?

It is two distant regions with opposing affinities for water

What are membrane carbohydrates for?

• Cell recognintion

• Adhesion

• Structural integrity

What transport type is the sodium potassium pump?

Active

Defien Phagocytosis?

Ingestion of large particles

What are the substances required for facilitated diffusion?

• Glucose

• Amino Acids

• Ions

• Water

How do Ions cross the membrane?

Through the protein channels

What is wrapped around DNA?

Proteins called histones

What is the Human Chromosome Number?

• Each somatic cell contains 46 chromosomes

• The 46 chromosomes are organised into 23 homoogous pairs.

What are the charcteristics od Homologous pairs?

• 22 pairs are autosomes which control most body functions and traits

• 1 pair are sec chromosomes (XX or XY), determines biological gender

what is diploid?

refers to the name of somatic cells that contain two complete sets of chromosomes.

What is the function of the Microtubule Organisisng Centre (MTOC), and diffrence in animal cells?

• Organises the microtubules that form the mitotic spindle

• Directs spindle fibre formation

• Ensures chromosomes are seperated accurately during mitosis

• Animal cells: the MTOC includes centrosomes

What is Mitosis?

A stage in the cell cycle during which the nucleus divides, ensuring accurate seperation of duplicated chromosomes into two new nuclei.

What is the primary purpose of Mitosis?

ensure each daughter cell receives an idential set of chromosomes, containing the same genetic information as the parent cell.

What are the key biological processes for Mitosis?

• Growth during development

• Replacement of worn out or damaged cells

• Tissue repair following injury

What are the six phases of Mitosis?

1. Prophase

2. Metaphase

3. Anaphase

4. Telophase

5. Cytokinesis

What occurs in prophase? (Stage of Mitosis)

• Chromatin condenses into distinct chromosomes

• The nucleous disappears

• Centrosomes move toward opposite side of the cell

• Spindle fibres begin to form between centrosomes

What occurs during Prometaphase? (Stage of Mitosis)

• The nuclear envelope breaks down completly

• Kinetochores form at the centromeres of chromosomes

• Spindle fibres attach to kineochores

• Chromosomes begin moving within the cell

What occurs during metaphase? (Stage of mitosis)

• Chromosomes align at the metaphase plate, the centre of the cell

• Spindle fibres apply equal tension from opposite poles

• The spindle assembly checkpoint verfies that all chromsomes are correctly attacthed

• This checkpoint is critical for preventing chromosomes mis-segregation