Unit 1 Topic 1: Cells as the basis of life

Question 1

Compare Prokaryotic and Eukaryotic cells

Answer 1

🦠 Prokaryotic: Small, no nucleus, no organelles, binary fission (e.g., bacteria).

🧬 Eukaryotic: Larger, nucleus, organelles, mitosis/meiosis (e.g., plants, animals).

✨ Key Difference: Nucleus & Organelles!

Question 2

What is the function of the nucleus

Answer 2

The nucleus controls cell activities and stores genetic information (DNA). It regulates gene expression, cell growth, and division (mitosis). The nucleolus inside produces ribosomes.

✨ Key Role: The “Control Center” of the Cell!

Question 3

What is the function of the mitochondria

Answer 3

Mitochondria produce energy (ATP) through aerobic respiration. They are known as the “powerhouse of the cell”, supplying energy for cell activities.

✨ Key Role: Energy Production!

Question 4

What is the function of the rough ER

Answer 4

The rough endoplasmic reticulum (RER) helps in protein synthesis and transport. It has ribosomes on its surface, which make proteins that are sent to the Golgi apparatus for modification and export.

✨ Key Role: Protein Production & Transport!

Question 5

What is the function of ribosomes

Answer 5

Ribosomes synthesize proteins by assembling amino acids based on genetic instructions (mRNA). They are found free in the cytoplasm or attached to the rough ER.

✨ Key Role: Protein Factory!

Question 6

What is the function of smooth ER

Answer 6

The smooth endoplasmic reticulum (SER) makes lipids (fats), detoxifies harmful substances, and stores calcium. It has no ribosomes on its surface.

✨ Key Role: Lipid Production & Detox!

Question 7

What is the function of Golgi apparatus

Answer 7

The Golgi apparatus modifies, sorts, and packages proteins and lipids from the ER for transport to their destination, either inside or outside the cell. It also produces lysosomes.

✨ Key Role: Packaging & Distribution Center!

Question 8

What is the function of lysosomes

Answer 8

Lysosomes contain digestive enzymes that break down waste materials, old organelles, and foreign substances (like bacteria). They are the cell’s “cleanup crew”.

✨ Key Role: Digestion & Waste Removal!

Question 9

What is the function of vacuoles

Answer 9

Vacuoles store water, nutrients, and waste products. In plant cells, the central vacuole maintains turgor pressure (helps keep the cell rigid) and stores important substances like sugars and pigments.

✨ Key Role: Storage & Support!

Question 10

What is the function of chloroplasts

Answer 10

Chloroplasts are responsible for photosynthesis. They capture light energy and convert it into chemical energy (glucose) using carbon dioxide and water. This process produces oxygen as a byproduct.

✨ Key Role: Photosynthesis & Energy Production!

Question 11

What is mitosis

Answer 11

Mitosis is the process by which a single eukaryotic cell divides to produce two identical daughter cells. It involves the replication and equal distribution of the cell’s DNA to ensure both cells have the same genetic material.

✨ Key Role: Growth, Repair, & Asexual Reproduction!

Question 12

What is cell differentiation

Answer 12

Cell differentiation is the process by which a less specialized cell becomes a more specialized cell with a specific function. It occurs during development when stem cells transform into different types of cells (e.g., muscle cells, nerve cells, skin cells) based on genetic instructions and environmental signals.

✨ Key Role: Specializing Cells for Specific Functions!

Question 13

What are the stages of mitosis

Answer 13

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
5. Cytokinesis

Question 14

Describe how stem cells originate through the process of mitosis and differentiate into specialised cells to form tissues.

Answer 14

Mitosis: Stem cells divide to form more stem cells or specialized cells.
Differentiation: Cells specialize into different types.
Tissues: Specialized cells form tissues.
✨ Key Process: Mitosis creates stem cells, and differentiation forms specialized cells.

Question 15

What are unipotent stem cells

Answer 15

Unipotent stem cells can only produce one type of specialized cell. They have the ability to self-renew, but their differentiation is limited to a single cell type.

✨ Key Role: Produce one specific cell type.

Question 16

What are multipotent stem cells

Answer 16

Multipotent stem cells can differentiate into several related cell types, but not all types. They are more specialized than pluripotent stem cells but can still give rise to a range of cell types within a specific tissue or organ.

✨ Key Role: Produce multiple related cell types.

Question 17

What are pluripotent stem cells

Answer 17

Pluripotent stem cells can differentiate into any type of cell in the body, except those needed to support a fetus (e.g., placenta). They have the ability to form any tissue or organ.

✨ Key Role: Can become any cell type in the body.

Question 18

What are totipotent stem cells

Answer 18

Totipotent stem cells can differentiate into any cell type, including those needed to form an entire organism (e.g., placenta and embryo). They have the greatest potential and can give rise to all cell types.

✨ Key Role: Can become any cell type, including embryonic and extra-embryonic tissues.

Question 19

Compare active and passive transport

Answer 19

Active Transport: Requires energy (ATP), moves substances against the gradient.
Passive Transport: No energy needed, moves substances down the gradient.

Question 20

Explain how the size of a cell is limited by surface area-to-volume ratio and rate of diffusion.

Answer 20

As a cell grows, its volume increases faster than its surface area, reducing the efficiency of material exchange. Smaller cells have a higher surface area-to-volume ratio, allowing faster diffusion. Larger cells struggle with slower diffusion and less efficient exchange.

Question 21

Describe how the hierarchical organisation of cells allow multicellular organisms to obtain nutrients e.g digestive and circulatory systems

Answer 21

Specialized cells (e.g., epithelial cells in the digestive system) perform specific functions like absorption.

Question 22

Describe how the hierarchical organisation of tissues allow multicellular organisms to obtain nutrients e.g. digestive and circulatory systems

Answer 22

Groups of similar cells form tissues (e.g., muscle tissue helps move food through the digestive tract).

Question 23

Describe how the hierarchical organisation of organs allow multicellular organisms to obtain nutrients e.g. digestive and circulatory systems

Answer 23

Tissues combine to form organs (e.g., stomach, where food is broken down and nutrients are absorbed).

Question 24

Describe how the hierarchical organisation of systems allow multicellular organisms to obtain nutrients e.g. digestive and circulatory systems

Answer 24

Organs work together in systems (e.g., digestive system breaks down food, and circulatory system transports nutrients to cells).

Question 25

Describe how the hierarchical organisation of cells allow multicellular organisms to exchange gases e.g. respiratory and circulatory systems

Answer 25

Cells: Specialized cells (e.g., alveolar cells in the lungs) are involved in gas exchange by directly absorbing oxygen and releasing carbon dioxide.

Question 26

Describe how the hierarchical organisation of tissues to allow multicellular organisms to exchange gases e.g. respiratory and circulatory systems

Answer 26

Groups of similar cells form tissues (e.g., epithelial tissue in the lungs allows efficient gas diffusion).

Question 27

Describe how the hierarchical organisation of organs allow multicellular organisms to exchange gases e.g. respiratory and circulatory systems

Answer 27

Tissues work together to form organs (e.g., lungs, where gas exchange occurs with the environment).

Question 28

Describe how the hierarchical organisation of systems allow multicellular organisms to exchange gases e.g. respiratory and circulatory systems

Answer 28

Organs combine into systems (e.g., the respiratory system for gas exchange, and the circulatory system to transport gases to and from cells).

Question 29

Describe how the hierarchical organisation of cells allow multicellular organisms to remove wastes e.g. respiratory, circulatory and excretory systems.

Answer 29

Specialized cells (e.g., kidney cells) are responsible for filtering waste from the bloodstream.

Question 30

Describe how the hierarchical organisation of tissues allow multicellular organisms to remove wastes e.g. respiratory, circulatory and excretory systems.

Answer 30

Groups of similar cells form tissues (e.g., renal tissue in kidneys for waste filtration).

Question 31

Describe how the hierarchical organisation of organs allow multicellular organisms to remove wastes e.g. respiratory, circulatory and excretory systems.

Answer 31

Tissues work together to form organs (e.g., kidneys filter waste, lungs remove carbon dioxide, and skin expels sweat).

Question 32

Describe how the hierarchical organisation of systems allow multicellular organisms to remove wastes e.g. respiratory, circulatory and excretory systems.

Answer 32

Organs function together in systems (e.g., the excretory system removes waste, and the circulatory system transports waste to organs for elimination).

Question 33

What are protein channels

Answer 33

Protein channels are membrane proteins that form pores in the cell membrane, allowing specific molecules or ions to pass through. They are essential for facilitated diffusion, helping substances move across the membrane without using energy. ✨Key Role: Allow specific molecules (like ions or water) to move in and out of cells.

Question 34

What are phospholipids

Answer 34

Phospholipids are molecules that make up the cell membrane. They have a hydrophilic (water-loving) head and hydrophobic (water-fearing) tails. This structure forms a bilayer, with heads facing outward and tails facing inward, creating a semi-permeable barrier. ✨ Key Role: Form the basic structure of the cell membrane, controlling what enters and exits the cell.

Question 35

What are cholesterol

Answer 35

Cholesterol is a lipid found in the cell membrane. It helps maintain the fluidity and stability of the membrane by preventing it from becoming too rigid or too fluid, ensuring proper cell function. ✨ Key Role: Stabilizes the cell membrane and maintains its flexibility.

Question 36

What are glycoproteins

Answer 36

Glycoproteins are proteins with carbohydrate chains attached to them. They are found on the cell membrane and play a key role in cell recognition, communication, and immune response. ✨ Key Role: Assist in cell recognition and signaling, allowing cells to interact with each other.

Question 37

Describe the structure and function of the cell membrane based on the fluid mosaic model, including the role of protein channels, phospholipids, cholesterol and glycoproteins.

Answer 37

The cell membrane is made up of phospholipids, protein channels, cholesterol, and glycoproteins. Phospholipids form a bilayer, controlling what enters/exits the cell. Protein channels allow specific molecules to pass through. Cholesterol keeps the membrane stable and flexible. Glycoproteins help with cell recognition and communication. ✨ Key Role: The membrane controls material movement and helps cells communicate.

Question 38

what is osmosis

Answer 38

Osmosis is the movement of water molecules from an area of low concentration of solute to an area of high concentration of solute, through a semi-permeable membrane. ✨ Key Role: Balances water concentration inside and outside the cell.

Question 39

what is simple diffusion

Answer 39

Simple diffusion is the movement of molecules from an area of high concentration to an area of low concentration without the need for energy or a membrane protein. ✨ Key Role: Allows gases (like oxygen) and small molecules to move across the cell membrane naturally.

Question 40

what is facilitated diffusion

Answer 40

Facilitated diffusion is the movement of molecules across the cell membrane through protein channels or carriers, from an area of high concentration to an area of low concentration, without using energy. ✨ Key Role: Helps larger or charged molecules (like glucose or ions) cross the membrane.

Question 41

what is protein-mediated active transport

Answer 41

Protein-mediated active transport uses membrane proteins (pumps) and ATP to move molecules against their concentration gradient, from areas of low concentration to high concentration. ✨ Key Role: Actively moves substances into or out of the cell, even against the gradient.

Question 42

What is endocytosis and exocytosis

Answer 42

Endocytosis: The process where a cell engulfs external material by wrapping its membrane around it, forming a vesicle. Exocytosis: The process where a cell releases substances by fusing a vesicle with the cell membrane. ✨ Key Role: Endocytosis brings substances into the cell, while exocytosis expels them out.

Question 43

Explain how the cell membrane regulates movement of substances into and out of the cell via by osmosis

Answer 43

The cell membrane uses osmosis to balance water and solute levels, ensuring cell stability.

Question 44

Explain how the cell membrane regulates movement of substances into and out of the cell via by simple diffusion

Answer 44

The membrane controls substance flow via simple diffusion based on size and concentration gradients.

Question 45

Explain how the cell membrane regulates movement of substances into and out of the cell via by facilitated diffusion

Answer 45

facilitated diffusion allows regulated, energy-efficient transport of molecules that can't diffuse directly through the lipid bilayer.

Question 46

What are cells

Answer 46

Cells are the building blocks of life, carrying out processes like energy production, growth, and reproduction.

Question 47

What are tissues

Answer 47

Tissues are groups of similar cells that work together to perform specific functions in an organism.

Question 48

What are organs

Answer 48

Organs are structures composed of different tissues that work together to perform specific functions in the body (e.g., the heart pumps blood, and the lungs facilitate gas exchange). ✨ Key Role: Organs carry out specialized tasks essential for life.

Question 49

What is cholesterol

Answer 49

Cholesterol is a lipid molecule found in cell membranes. It intersperses among phospholipids, helping to maintain membrane fluidity and stability across various temperatures. It also serves as a precursor for hormones, bile acids, and vitamin D. ✨ Key Role: Regulates membrane properties and serves as a building block for essential molecules.

Question 50

What are glycoproteins

Answer 50

Glycoproteins are proteins with sugar chains attached. They are located on the cell surface and play a crucial role in cell recognition, communication, and immune response. ✨ Key Role: Facilitate cell interaction and signaling.

Question 51

Describe the structure and function of the cell membrane based on the fluid mosaic model, including the role of protein channels, phospholipids, cholesterol and glycoproteins.

Answer 51

Phospholipids form a bilayer that creates a selective barrier. Protein Channels allow specific molecules to move in and out. Cholesterol is interspersed to maintain stability and fluidity. Glycoproteins on the outer surface help with cell recognition and signaling. ✨ Key Role: Controls material exchange and cell communication.

Question 52

What is endocytosis and exocytosis

Answer 52

Endocytosis: The cell membrane engulfs external materials, forming a vesicle to bring them into the cell. Exocytosis: Vesicles inside the cell fuse with the cell membrane to release substances outside. ✨ Key Role: They allow the cell to import nutrients and expel waste.

Question 53

What is active transport

Answer 53

Active transport is the movement of molecules against their concentration gradient (low to high concentration) using energy (ATP) and protein pumps in the cell membrane. ✨ Key Role: Helps cells absorb essential nutrients and remove waste efficiently.

Question 54

What is passive transport

Answer 54

Passive transport is the movement of molecules down their concentration gradient (high to low concentration) without using energy. It includes osmosis, simple diffusion, and facilitated diffusion. ✨ Key Role: Allows efficient movement of substances without energy use.