Lecture 2

Question 1

Who advanced neuroscience the most

Answer 1

Darwin

All animals in the world have a lot in common as they are all descended from a common ancestor

Question 2

Timeline of universe

Answer 2

13.7 billion years old

tjhis is the oldest light we can see

this light originated from a space, 46 billion years away from us (cos universe is expanding)

Question 3

Atoms and molecules

Answer 3

all matter is made of atoms

elements consist only of one of these atoms

118 elements

The air we breathe is 99% N2 and O2
Usually form molecules

Question 4

Chemical reactions

Answer 4

is when a chemical bond is formed, broken or modified. Living things regulate these reactions to do things

Question 5

Ions

Answer 5

If a molecule or atom has a charge, it is called an ion

Cations positive
Anions negative

Ions often form ionic bonds with each other

Atoms held together with ionic bonds are called salts and dissolve in water

Question 6

Evolution

Answer 6

earth is 4.5 billion years ago

life created in primordial soup in the first billion years

Question 7

CHNOPS

Answer 7

The main elements of cells are

59% Hydrogen
25% Oxygen
11% Carbon
4% Nitrogen
2% Others

Question 8

Origin of life

Answer 8

Lightning hits soup with water (essential for life) and many chemical compounds
By chance, lighting causes chemical reactions
Blob of oil engulfs DNA
Creates the first cell, ancestor of all life

Could self-replicate

Question 9

Molecules of life

Answer 9

CHNOPS come together to make

Water H2O

Sugar (rings of carbons)

Lipids (long, hydrocarbon chains

Nucleic acids

Amino acids

Question 10

Chains of life

Answer 10

Almost everything in life chemically is a chain

shains of sugars = carbohydrate

Chains of nucleic acids = chromatin (or folded, chromosomes)

Lipids form sheets ehich make all membranes and vesicular membranes

Question 11

The molecular composition of cells

Answer 11

70% water

15% sugars

10% lipids

15% nucleic acids

50% AAs

10% other organic molecules

Question 12

RNA enzymes

Answer 12

refers to ribonucleic acids

String RNA together, it folds up

Sometimes these have enzymatic activity

Some can self-replicate

The first self replicating molecule was RNA

Question 13

Phospholipd bilayer

Answer 13

Strands of fat with a phosphate cap

Lipids avoid water, phosphate is drawn to it

Thus forms bi-layers

Under some conditions, form micelles (balls) and explode and reform , forming liposomes.

The cell membrane is essentially a liposome

The interior is full of salt water

Question 14

RNA to DNA

Answer 14

RNA is not stable

It was replaced by DNA. DNA has no enzymatic activity and is more stable.

RNA is not abundant (not many types). There is a greater abundance of AAs so we use them to make enzymes etc

RNA based enzymes probably started to incorporate proteins and eventually were replaced by them

Question 15

over the last 3.5 billion years (4 things)

Answer 15

All instructions of life stored as DNA\
Sections of DNA are transcribed into RNA
RNA gets translated into proteins
Protein catalyses chemical reactions

Question 16

Transcription

Answer 16

Where the gene is switched on
RNA polymerase attaches to the gene (DNA)
Moves along DNA making a strand of mRNA from free bases present in the nucleus
DNA code determines the order in which RNA bases are attached

This is then processed which involves adding and removing sections of RNA

Note these genes can be read in alternative ways which can result in different forms of the same protein (isoforms). Several isoforms are made from the same gene.

Question 17

Translation

Answer 17

The mRNA leaves the nucleus and goes to a ribosome
There are 20 AAs
tRNA takes these AAs to the ribosome the mRNA is read 3 bases at a time, each coding for an AA
tRNA delivers this AA
The AA is added to the growing chain
When this is finished, it folds into a complicated 3D shape

in this way RNA is translated at the ribosome

Question 18

The prokaryotic cell

Answer 18

Consists of a plasma membrane, cytoplasm, chromatin (loose strings of DNA) and ribosomes (nucleic acid - mostly RNA - and proteins)

Question 19

Proteins

Answer 19

are what does things in cells

Enzymes

Receptors

Myotubules, messengers, transport and storage

Question 20

Eukaryote origins

Answer 20

1 billion years after life, prokaryotes existed
There were larger and smaller ones
The large ate the small

One day a small one had a defense that allowed tit to survive in the larger cell
One time, a symbiotic relationship formed and the small cell became dedicated to metabolizing sugar

The first mitochondria

Question 21

ATP

Answer 21

power source

When ATP binds with a protein, releases a phosphate. The energy of ATP>ADP changes the shape of the protein

Question 22

The eukaryotic cell

Answer 22

Nucleus
Membrane bound
No chromatin, tightly folded chromosomes

Mitichondria have their own DNA

ER, golgi body

Lysoosomes

Question 23

Eukaryotic Cell body (SOMA)

Answer 23

is where the nucleus is located

A nerve cell is defined by where the soma is located (eg a hippocampal neuron)

Cell membrane defines the boundary

Question 24

Microtubules

Answer 24

proteins

roads

kenisins walk along them
globular heads act as feet
one binds with tubule, the other ATP and uses its energy to flip them over thus appears to walk

Each has a neck attached to cargo

They can carry much bigger cargo than them but still get blocked by cellular components sometimes so use multiple at once

Typically take stuff from cell body to periphery

100 steps/8nm per secons

Question 25

Multicellular organisms

Answer 25

One day cells did not divide fully and stuck together
DNA codes for when to switch on or off expression
Eg if cold, bind here, if not, dont
SO binding points are turned on or off

Cells specialise too eg if your cell is on the edge, become hard etc

Question 26

Animal studies

Answer 26

because all have a common ancestor, you can study animals nerve systems

Giant squid = action potential (Nobel in 1963)

Sea Slug = learning and memory (2000 Nobel)

Question 27

Brains in mammals

Answer 27

Brain structure is similar in mammals
40% of mammals are rodents, 20 are bats

Rodents are evolutionary closer to humans so we use them

Question 28

justification for animal studies

Answer 28

1 - mental disease is real, the ends justify the means

2 - no one is cruel. No one enjoys it, you stomach it

3 - must have ethics board approval. Always checks and balances

Question 29

Evolution of the human brain

Answer 29

Great apes and us share 98.8 % of DNA

Research on them is not allowed

Still there is a massive cognitive difference between them and us and we do not know why.

Maybe it is the pattern of expression

Question 30

Birth and the brain

Answer 30

The human brain develops after birth. Production of new neurons almost ceases but those present grow and establish connections with each other. Other brain cells that support neurons proliferate

4x more massive from birth to 20. 1400g

neoteny extended youth

Question 31

Fermi Paradox

Answer 31

40 billion planets like earth in the milky way
13 billion years old so some earth like planets are much older
if interstellar travel is possible, even the slow kind within the reach of earth it would take 5-50 million years to colonize the galaxy
There are 2 trillion galaxies in the known universe

So… Where is everybody?