Cell Biology Basics

Questions and Answers

What is the cell membrane made up of?

Phospholipids bilayer, proteins and cholesterol.

What does the cell membrane do?

The cell membrane has a fluid semi-permeable barrier against harmful mutations and is used as a getaway for desired materials.

What is the purpose of the cytoplasm?

Cytoplasm is a jelly-like substance responsible for supporting the organs and providing nutrients to the cell.

What is the mitochondria and what takes place in it?

The powerhouse of the cell where cellular respiration takes place. Signup and view all the answers

What is the folded membrane of a mitochondria called?

Cristae. Signup and view all the answers

What takes place in chloroplasts?

Photosynthesis. Signup and view all the answers

Why do thylakoids stack?

Thylakoids stack to increase surface area which means more energy can be generated. Signup and view all the answers

Why do plants have a cell wall?

To provide its rigid structure since they don't have bones. Signup and view all the answers

What is an enzyme?

An enzyme is a protein that speeds up reactions without being used itself. Signup and view all the answers

What do substrates bind to on the enzyme?

The active site. Signup and view all the answers

What are the two types of active sites?

Induced Fit model Signup and view all the answers

What is denaturing?

Denaturing occurs when high temperature or high pH breaks hydrogen bonds, changing the shape of the active site. Signup and view all the answers

What are inhibitors?

An inhibitor stops an enzyme from binding with its substrate by changing the shape of the active site. Signup and view all the answers

What are competitive inhibitors?

Binds to the active site Signup and view all the answers

What are non-competitive inhibitors?

Binds to an alternative site to change the active site Signup and view all the answers

What is simple diffusion?

The movement of small uncharged molecules across a semipermeable membrane from high to low concentration. Signup and view all the answers

What is facilitated diffusion?

The movement of large and charged molecules from high to low concentration through proteins. Signup and view all the answers

What is osmosis?

The movement of water across a semipermeable membrane from high water potential to low water potential. Signup and view all the answers

What is active transport?

Movement of substances from low concentration to high concentration using specific proteins. Signup and view all the answers

What is cytosis?

Transport mechanism of bulk quantities of molecules into and out of cells by folding of membranes. Signup and view all the answers

What is endocytosis?

The taking in of substances into the cell by infolding of membranes. Signup and view all the answers

What is tonicity?

Measurement of water on either side of a semi-permeable cell membrane. Signup and view all the answers

What is hypertonic?

High concentration of solutes outside the cell. Signup and view all the answers

What is hypotonic?

High concentration of solutes inside the cell. Signup and view all the answers

What is isotonic?

The concentration of solutes is the same inside and outside the cell. Signup and view all the answers

What will happen to an animal and plant cell in a hypertonic solution?

Animal cell will shrivel, plant cell will become plasmolysed Signup and view all the answers

What will happen to an animal and plant cell in a hypotonic solution?

Animal cell will burst, plant cell will become turgid Signup and view all the answers

What will happen to an animal and plant cell in an isotonic solution?

Animal cells will remain unchanged, plant cells will become flaccid Signup and view all the answers

What is photosynthesis?

Process of using light energy to convert water and carbon dioxide into glucose. Signup and view all the answers

What is the photosynthesis equation?

6CO2 + 6H2O = C6H12O6 + O2 Signup and view all the answers

Why is light needed for photosynthesis?

Light is absorbed by chlorophyll to turn light energy into chemical energy for photosynthesis. Signup and view all the answers

What is the light-dependent phase of photosynthesis?

Occurs in the thylakoid membrane, where solar energy is converted into ATP and water is split. Signup and view all the answers

What is the light-dependent equation?

CO2 + ATP = C6H12O6 Signup and view all the answers

What is the light-independent phase of photosynthesis?

Does not require sunlight and happens in the stroma for glucose production. Signup and view all the answers

What increases photosynthesis?

Higher temperature, higher light intensity, and higher CO2 concentration. Signup and view all the answers

What decreases photosynthesis?

Too high temperature, decrease in water, and light wavelength. Signup and view all the answers

What is cellular respiration?

Converts glucose into ATP. Signup and view all the answers

Study Notes

Cell Membrane Structure and Function

Composed of a phospholipid bilayer, proteins, and cholesterol.
Acts as a semi-permeable barrier protecting against harmful mutations and allowing selective passage of materials.

Cytoplasm

Jelly-like substance supporting organelles and providing nutrients to the cell.

Mitochondria

Known as the powerhouse of the cell, responsible for cellular respiration.
Converts glucose into ATP (energy).
Internal folded membrane called cristae increases surface area for energy production.

Chloroplasts and Photosynthesis

Site of photosynthesis where light energy is converted into glucose.
Thylakoids stack into structures called grana to enhance surface area for energy generation.

Plant Cell Wall

Provides rigid structure and support, compensating for the absence of bones.

Enzymes

Proteins that act as biological catalysts, speeding up chemical reactions without being consumed.
Substrates bind to enzymes at the active site.
Two types of active sites: lock and key model; induced fit model.

Enzyme Denaturation and Inhibition

Denaturation occurs due to high temperature or pH, altering the active site's shape and functionality irreversibly.
Inhibitors prevent substrate binding by altering the active site; competitive inhibitors bind to the active site, while non-competitive inhibitors bind elsewhere.

Transport Mechanisms

Simple Diffusion: Movement of small uncharged molecules from high to low concentration across a membrane.
Facilitated Diffusion: Movement of large or charged molecules through protein channels from high to low concentration.
Osmosis: Movement of water from high water potential to low water potential across a semi-permeable membrane.
Active Transport: Movement against concentration gradient (low to high) using protein pumps.
Cytosis: Bulk transport of molecules by membrane folding. Includes endocytosis (taking substances into the cell).

Tonicity

Measurement of solute concentration in relation to the cell's internal environment.
Hypertonic: Higher solute concentration outside the cell; animal cells shrivel and plant cells become plasmolysed.
Hypotonic: Higher solute concentration inside the cell; animal cells may burst while plant cells become turgid.
Isotonic: Equal solute concentration; animal cells remain unchanged, and plant cells become flaccid.

Photosynthesis

Converts light energy into glucose from water and carbon dioxide.
Photosynthesis equation: 6CO2 + 6H2O = C6H12O6 + 6O2.
Light is essential for photosynthesis, absorbed by chlorophyll in chloroplasts, converting light energy into chemical energy.

Photosynthesis Phases

Light-dependent Phase: Occurs in thylakoids; solar energy splits water to produce oxygen and ATP.
Light-independent Phase: Occurs in the stroma; uses ATP to convert carbon dioxide and hydrogen into glucose.

Factors Affecting Photosynthesis

Increases: Higher temperature, light intensity, and CO2 concentration.
Decreases: Excessively high temperatures, reduced water supply, and unfavourable light wavelengths.

Cellular Respiration

Process of converting glucose into ATP, storing energy for cellular activities.

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Explore the core concepts of cell biology, including the structure and function of the cell membrane, cytoplasm, and mitochondria. This quiz will test your understanding of how these components work together to maintain cell health and function.