Lecture 1 - In the beginning

What are the three common features of life?

proton gradients, reducing power, atp

What is a proton gradient?

difference in h concentration across a membrane that stores energy

What is reducing power?

ability to donate electrons to other molecules

What is the difference between oxidation and reduction?

oxidation is loss of electrons, reduction is gain of electrons

What is the difference between a reducing agent and an oxidising agent?

reducing agent donates electrons, oxidising agent accepts electrons

What are the reduced forms of NAD⁺, NADP⁺ and FAD?

nadh, nadph, fadh2

What is ferredoxin?

iron sulphur protein that transfers electrons

What is the difference between ATP and NADPH?

atp provides energy, nadph provides electrons

What does a high NADH/NAD⁺ ratio indicate?

highly reduced cell

What does high ATP concentration indicate?

high energy state in cell

What does LUCA stand for?

last universal common ancestor

What were the main characteristics of LUCA?

anaerobic, hydrogen-dependent and thermophilic

What does thermophilic mean?

adapted to high temperatures

What energy source did LUCA likely use?

hydrogen

Where might early life have originated?

around alkaline hydrothermal vents

What are the two main types of hydrothermal vents?

black smokers and white smokers

How did alkaline vents create a natural proton gradient?

water had a higher pH than the surrounding ocean, creating a difference in H⁺ concentration

What did alkaline vents provide for early life?

hydrogen, minerals, iron-sulphur compounds and proton gradients

What was the role of iron-sulphur clusters in early life?

transferred electrons from hydrogen to CO₂

What happens when CO₂ is reduced?

forms reduced carbon compounds used to build biological molecules

What does ATP synthase do?

uses a proton gradient to produce ATP

What does Ech or RET do?

uses a proton gradient to generate reduced ferredoxin

What are methanogens?

archaea that produce methane

How do methanogens produce methane?

use hydrogen to reduce CO2

Why are methanogens important when studying LUCA?

similarities to the metabolism of LUCA