FoB: Lecture 5 slides - cells & evolution

What is the toxin secreted by the newt mentioned in the notes?

Tetrodotoxin or TTX.

What is the overarching concept discussed in Lecture 5?

Prokaryotic and eukaryotic cells evolved from a universal common ancestor.

What is the average composition of cells?

- 70% water

- 30% chemicals

-including 15% proteins

- 7% nucleic acids

- 4% small molecules (ions)

- 2% lipids

- 2% carbohydrates.

What does LUCA stand for?

Last Universal Common Ancestor.

What is LUCA described as?

The first cell on earth and the ancestor of all biological life on the planet.

What is hypothesized to be the result of chemical evolution?

The first cell.

What are the stages from primordial soup?

Stage 1: Inorganic molecules

Stage 2: Complex molecules

Stage 3: Life cell

What are some early forms of life?

Earliest animals, plants, fungi, multicellular life, and sexual reproduction.

What was the composition of the primordial soup likely to include?

Inorganic molecules such as H2S and NH3.

What are the main inorganic molecules present in the primordial soup on early Earth?

H2O, CH4, NH3, CO2, H2S.

What is the significance of white smoker hydrothermal vents in the context of early Earth?

They contained minerals, simple chemical compounds, and an energy gradient essential for chemical evolution.

What is Stage 1 of chemical evolution?

Building complex biomolecules from primordial soup.

What are the two main requirements for a molecule to be considered a replicator?

1) It must contain information that leads to its replication

2) It must cause itself to replicate based on that information's interaction with the environment.

What does the RNA-world hypothesis propose?

RNA was likely the molecular replicator responsible for kick-starting life on Earth.

What are ribozymes?

RNAs that can catalyze chemical reactions.

How do RNAs replicate?

They hold information for making copies of themselves through hydrogen bonding in base pairing of nucleic acids.

What is Stage 2A of chemical evolution?

The rise of replicators, particularly RNA replicators.

What is Stage 2B in the context of chemical evolution?

Formation of phospholipid bubbles.

Why do phospholipids form bilayers?

Because they are amphipathic, allowing for separation of the internal environment from the outside world.

What is the benefit of being protected from the environment for early cells?

It allows for a stable internal environment necessary for biochemical processes.

What is the last universal common ancestor?

The most recent common ancestor of all current life on Earth, including eukaryotes, archaea, and bacteria.

What are the three main tenets of cell theory?

1) All living things are composed of one or more cells

2) Cells are the basic units of structure and function in living things

3) All cells arise from pre-existing cells.

What are some key properties of life associated with cells?

Life, reproduction, homeostasis, evolution, behavior, biochemical processes, energy consumption and synthesis, signaling, adaptation.

What properties are important in understanding cell structure?

Mass, charge, electronegativity, bonds, hydrophobic, hydrophilic, amphipathic, diffusion, osmosis, van der Waals.

What is the function of fluorescing probes in microscopy?

They label specific structures and molecules.

What are the common features of all cells on Earth?

- Cell membrane

- cytoplasm

- genome of DNA

- ribosomes

What is the composition of the cell membrane?

A phospholipid bilayer that surrounds the fluids and structures of a cell.

What are the key features of prokaryotic cells?

- Rigid cell wall (peptidoglycan in bacteria)

- additional outer plasma membrane

- slimy capsule of polysaccharide

- genome in cytoplasm

What is the function of a flagellum in prokaryotes?

It is a whip-like protein complex that allows prokaryotes to move.

What are fimbriae in prokaryotes?

Hair-like projections that allow prokaryotes to stick to surfaces.

How do prokaryotes demonstrate diversity?

They are smaller but diverse in structure and metabolism

- found everywhere

- can use various energy sources

- exist as free-living or in aggregates.

What is the evolutionary relationship between eukaryotic and prokaryotic cells?

Eukaryotic cells evolved from a prokaryotic ancestor.

What process led to the formation of organelles in eukaryotic cells?

The cell membrane invaginated or migrated to surround different parts of the cytoplasm.

What is endosymbiosis?

A mutually beneficial relationship between two organisms, where one (endosymbiont) lives inside the body of the other (host).

What is the significance of the Endoplasmic Reticulum (ER) in cell evolution?

The ER was probably the first proto-organelle to form from the cell membrane and later enclosed the DNA to form the nucleus.

What are the key differences between prokaryotic and eukaryotic cells?

Prokaryotic cells:

- lack distinct, membrane-bound compartments

- have DNA in circular chromosomal form

eukaryotic cells:

- have membrane-bound organelles

- DNA in linear chromosomal form

What are three structures that plant cells have that animal cells do not?

1. A cell wall surrounding the plasma membrane

2. chloroplasts for energy synthesis

3. a large central vacuole

What are examples of organelles found in eukaryotic cells?

Nucleus, mitochondria, and chloroplasts.

What is phagocytosis and which type of cells utilize this process?

Phagocytosis is a method by which prokaryotes eat, engulfing particles or other cells.

What is the size range of prokaryotic cells compared to eukaryotic cells?

- Prokaryotic cells range from 1 to 10 micrometers

- eukaryotic cells range from 10 to 100 micrometers.

What role does the cell membrane play in the formation of organelles?

The cell membrane invaginates and surrounds different parts of the cytoplasm to create organelles.