Biology all

What is the cell theory?

1. Living organisms are composed of cells

What are atypical cells and examples of them?

Cells that don't conform to the cell theory

1. striated muscle cells

How to calculate magnification?

magnification = image size/actual size

What are the functions of life in a cell?

Metabolism
Response
Homeostasis
Growth
Reproduction
Excretion
Nutrition
(MR H GREN)

How do paramecium carry out the functions of life?

Metabolism: Enzymes in their cytoplasm
Response: uses their cilia
Homeostasis: osmoregulation (collecting excess water in vacuole and expelling it through the cell membrane
Growth: as it consumed food, it enlarges
Excretion: through the anal pore
Nutrition: heterotroph and engulfs food

How does the Surface area to volume ratio limit cell size?

Surface area to volume ratio(high SA to V ratio is good)

What are the emergent properties of multicellular organisms?

What is cell differentiation?

newly formed cells become more specialised and distinct from one another as they mature

What are stem cells?

Stem cells are unspecialised cells that have two key qualities:

1. Self Renewal

How do stem cells treat stargardts disease?

What are the different types of stem cells?

Totipotent

What are the ethics of stem cells?

derived from embryos

What are prokaryotes

Prokaryotes are organisms whose cells lack a nucleus and are further classified in two domains:

What are eukaryotes

Eukaryotes are organisms whose cells contain a nucleus

They have a more complex structure and are believed to have evolved from prokaryotic cells and are compartmentalised by membrane

How is the electron microscope used?

Electron microscopes have two key advantages when compared to light microscopes:

How do prokaryotes divide?

through binary fission

What is the structure and functions of organelles in exocrine gland cells of the pancreas?

These are animal cells that are specialized to secrete large quantities of digestive enzymes

They will have all the organelles of an animal cell but will have many ribosomes and rough ER to create the enzymes which are proteins and transport them outside the cell.

What is the structure and functions of organelles in palisade mesophyll cells of the leaf?

They are basically plant cells with many chloroplasts.

They have many chloroplasts to allow the cell to carry out the maximum levels of photosynthesis

What are the amphipathic properties of phospholipid molecules?

Because phospholipids contain both hydrophilic (water

How is the membrane formed?

the interaction between hydrophilic phosphate heads and hydrophobic lipids (fatty acids)

What are the components of the membrane?

What are the functions of membrane proteins?

Junctions

What is the difference between integral proteins and peripheral proteins?

integral proteins are permanently attached to the membrane typically span the entire membrane (transmembrane) while peripheral proteins are temporarily attached by non

Why is cholesterol important for the animal cell membrane?

Why was the Davson

Danielli model falsified?

What is passive transport?

the movement of material along a concentration gradient (high concentration ⇒ low concentration)

What is facilitated diffusion?

Movement of specific molecules across cell membranes through protein channels

What is osmosis and how does it work?

is the movement of water or other solvent through a plasma membrane from a region of LOW solute concentration to a region of HIGH solute concentration. Osmosis is passive transport, meaning it does not require energy to be applied.

What is active transport?

Active transport involves the movement of materials against a concentration gradient (low concentration ⇒ high concentration)

What is Endocytosis and how does it work?

is a cellular process where cells take in molecules or substances from outside of the cell by engulfing them in the cell membrane and can be further divided into phagocytosis or pinocytosis.

What is exocytosis and how does it work?

the ejection of waste products or useful substances from the inside of the cell and occurs when a vesicle fuses with the plasma membrane, allowing its contents to be released outside the cell

How do vesicles move materials within cells?

Endoplasmic Reticulum:

What is the structure and function of sodium

potassium pump for active transport?

Why do tissues in muscles need to be bathed in a solution with the same osmolarity?

Tissues or organs to be used in medical procedures must be bathed in a solution with the same osmolarity
as the cytoplasm to prevent osmosis

What is a hypotonic solution?

Solutions with a relatively lower osmolarity are categorised as hypotonic (low solute concentration ⇒ loses water)

What are the affects of hypotonic solutions on plant and animal cells?

cells can swell and burst (not plant cells)

What is a hypertonic solution?

Solutions with a relatively higher osmolarity are categorised as hypertonic (high solute concentration ⇒ gains water)

What are the affects of hypertonic solutions on plant and animal cells?

cell loses water and animal cells can shrivel up while plant cells plasmolyze

How can cells only be formed by division of pre

existing cells?

How did the first cells arise from non

living material?

What is the endosymbiotic theory?

explains how eukaryotic cells may have evolved from prokaryotic cells

How did Pasteur's experiment show that spontaneous generation of cells and organisms do not occur now?

that emergent bacterial growth in nutrient broths was due to contamination by pre

What is Mitosis?

Mitosis is the process of nuclear division, whereby duplicated DNA molecules are arranged into two separate nuclei

What are the different phases of mitosis?

*P*rophase

Why is the interphase a very active phase of the cell?

The stage in the development of a cell between two successive divisions which is a continuum of three distinct stages:

*G1*

How do cyclins control the cell cycle

Cyclins are a family of regulatory proteins that control the progression of the cell cycle

Cyclins activate cyclin dependent kinases (CDKs), which control cell cycle processes through phosphorylation:

How do chromosomes condense?

by supercoiling during mitosis

What are the sequence of events in the 4 phases of mitosis

PMAT

What is cytokinesis?

the process of cytoplasmic division, whereby the cell splits into two identical daughter cells

How does cytokinesis differ from plant and animal cells?

animal cells create a cleavage furrow and pinches the cell into two while plant cells a cell plate forms and divides the cell into two.

What are mutagens?

A mutagen is an agent that changes the genetic material of an organism and may be physical, chemical, or biological in origin

What are oncogenes?

An oncogene is a gene that has the potential to cause cancer

What is metastasis?

Metastasis is the spread of cancer from one location (primary tumour) to another, forming a secondary tumour

How are mutagens, oncogenes, and metastasis involved in the development of primary and secondary tumors?

All mutagens can cause cancer. The most common physical mutagens are X

What is the difference between primary and secondary tumors?

What is a ribosome?

Structure: Two subunits made of RNA and protein; larger in eukaryotes (80S) than prokaryotes (70S)

Function: Site of protein synthesis (translation)

*universal organelle*

What is the cytoskeleton?

Structure: Network of fibres throughout the cytoplasm cytoplasm (fluid portion of the cytoplasm is the cytosol)

Function: Provides internal structure and mediates intracellular transport (less developed in prokaryotes)

*universal organelle*

What is the plasma membrane?

Structure: Phospholipid bilayer embedded with proteins (not an organelle per se, but a vital structure)

Function: Semi

What is the nucleus?

Structure: Double membrane structure with pores; contains an inner region called a nucleolus

Function: Stores genetic material (DNA) as chromatin; nucleolus is site of ribosome assembly (control centre of the cell

*eukaryotic organelle*

What is the endoplasmic reticulum?

Structure: A membrane network that may be bare (smooth ER) or studded with ribosomes (rough ER)

Function: Transports materials between organelles (smooth ER = lipids ; rough ER = proteins)

*eukaryotic organelle*

What is the golgi apparatus?

Structure: An assembly of vesicles and folded membranes located near the cell membrane

Function: Involved in the sorting, storing, modification and export of secretory products

*eukaryotic organelle*

Mitochondrion

Structure: Double membrane structure, inner membrane highly folded into internal cristae

Function: Site of aerobic respiration (ATP production)

*eukaryotic organelle*

What is a lysosome?

Structure: Membranous sacs filled with hydrolytic enzymes

Function: breaks down food into particles the rest of the cell can use and to destroy old cells

*animal cell only*

What is a chloroplast?

Structure: Double membrane structure with internal stacks of membranous discs (thylakoids)

Function: Site of photosynthesis

What is a vacuole?

Structure: Fluid

What is the cell wall?

Structure: External outer covering made of cellulose (not an organelle per se, but a vital structure)

Function: Provides support and mechanical strength; prevents excess water uptake

*plant cell only*

How to draw an animal cell

Key Features:

Nucleus

What are the challenges with stem cell therapy?

what are pili?

Structure: protein filaments on the cell wall

Function: helps in cell adhesion in DNA transfer between cells

what are flagella?

Structure: tail

what is the nucleoid region?

controls the activities in the cell and reproduction of organism (through binary fission)

What are plasmids?

Structure: Plasmids are small loops of extra DNA that aren't part of the chromosome.

Function: Plasmids contain genes for things like drug resistance and can be passed between bacteria.

How to draw Prokaryotic cells

Include:

How to draw plant cells

what are the 3 types of passive transport?

simple diffusion, facilitated diffusion, osmosis

what are the two types of active transport

Primary (direct) active transport

what is simple diffusion?

Diffusion is the net movement of molecules from a region of high concentration to a region of low concentration

what factors can influence the rate of diffusion?

Temperature (affects kinetic energy of particles in solution)

Molecular size (larger particles are subjected to greater resistance within a fluid medium)

Steepness of gradient (rate of diffusion will be greater with a higher concentration gradient)

What is osmolarity?

Osmolarity is a measure of solute concentration, as defined by the number of osmoles of a solute per litre of solution (osmol/L)

What is an isotonic solution?

Contains equal concentrations of solutes on both sides.

what is facilitated diffusion

is the passive movement of molecules across the cell membrane via the aid of a membrane protein

How does a channel protein work?

Integral lipoproteins which contain a pore via which ions may cross from one side of the membrane to the other

How do carrier proteins work?

Integral glycoproteins which bind a solute and undergo a conformational change to translocate the solute across the membrane

what is the difference between channel proteins and carrier proteins?

How does a pump work in active transport?

What is the process of ion exchange in a sodium

potassium pump?

What is the evidence for endosymbiosis

Mitochondria and chloroplasts are both organelles suggested to have arisen via endosymbiosis

*M*embrane

What is the cell cycle?

ordered set of events which culminates in the division of a cell into two daughter cells

It can be roughly divided into two main phases:

What is the M Phase?

The period of the cell cycle in which the cell and contents divide to create two genetically identical daughter cells

What is the difference between chromatin vs chromosomes

What is chromatin?

what is a chromosome?

how to identify mitotic cells

Prophase

what is the mitotic index?

The ratio between the number of cells in mitosis in a tissue and the total number of observed cells

What are organic compounds?

carbon

What are the four macromolecules?

What are the 4 most common biological elements?

Carbon, Hydrogen, Oxygen, Nitrogen

What are the advantages of Carbon?

What are functional groups?

part of organic molecules that is involved with chemical reactions

What is a hydroxyl group?