Week 11

Question 1

Name characteristics of living things

Answer 1

1. Have an Organized Structure
2. Are Composed of Organic Molecules and Cells
3. Grow and Reproduce (on their own!)
4. Respond to the Environment and its Changes
5. Have a Metabolism
   ◦ Take in Food
   ◦ Excrete Waste
   ◦ Maintains Homeostasis
6. Evolve and Adapt

Question 2

Difference in prokaryote and eukrayotes accoridng to DNA , organelles, reproduction, average size

Answer 2

1. DNA:
   
   • Prokaryotes: DNA is “naked” (not bound to proteins), circular, and usually lacks introns.
   • Eukaryotes: DNA is bound to proteins, linear, and usually contains introns.
2. Organelles:
   
   • Prokaryotes: No nucleus; no membrane-bound organelles; 70S ribosomes.
   • Eukaryotes: Has a nucleus; membrane-bound organelles; 80S ribosomes.
3. Reproduction:
   
   • Prokaryotes: Reproduce through binary fission; have a single chromosome (haploid).
   • Eukaryotes: Reproduce through mitosis and meiosis; chromosomes are paired (diploid or more).
4. Average Size:
   
   • Prokaryotes: Smaller (~1–5 µm).
   • Eukaryotes: Larger (~10–100 µm).

This chart is a helpful summary for distinguishing these two types of cells.

Question 3

What are the 4 major macromolecules and monomers prokaryote and eukaryote cells rely on ?

Answer 3

1. Protein
   
   • Monomer: Amino acids
2. Nucleic Acids (DNA, RNA)
   
   • Monomer: Nucleotides
3. Fats (Lipids)
   
   • Monomer: Glycerol and fatty acids
4. Carbohydrates (Complex sugars)
   
   • Monomer: Simple sugars (monosaccharides)

These macromolecules and their monomers play critical roles in the structure and function of cells across both cell types.

Question 4

Monomer

Answer 4

(“one-part”): a small molecule that can covalently bind
to other similar molecules to form a larger molecule, called a macromolecule
◦ For example – amino acids, monosaccharides, nucleotides, fatty acids and glycerol

Question 5

Polymer

Answer 5

Large number of monomers boded together

Question 6

Macromolecule

Answer 6

Any very large organic molecule, usually made up
of smaller molecules called monomers that join together into a polymer. The main macromolecules are proteins, nucleic acids (DNA/RNA), and polysaccharides (e.g., starch, cellulose)

Question 7

How did Eukaryotes airse

Answer 7

Endosymbiosis

Question 8

Explain endosymbiosis

Answer 8

1. Start with two independent bacteria.
2. One bacterium engulfs the other.
3. The engulfed bacterium begins to live inside the other.
4. Both bacteria benefit from the arrangement—the internal bacterium provides additional functions, like energy production.
5. The internal bacteria are passed on from generation to generation as part of the host cell, leading to the evolution of organelles like mitochondria and chloroplasts in eukaryotic cells.

This mutual relationship led to the development of complex eukaryotic cells from simpler prokaryotic ancestors.

Question 9

Where did chloroplastes come from

Answer 9

Endosymbiosis

Question 10

When did life originate

Answer 10

3.5 Billion years ago

Question 11

When did the earliest fossils emerge and what is it

Answer 11

3.45 Billion YO
* Evidence from microfossils and stromatolites found in S.Africa and Australia
* Produced by mainly photosynthesizing bacteria…
* But even these were relatively complex compared to the earliest precursor molecules

Question 12

What fundamental property of the universe does life defy

Answer 12

Entropy

Question 13

What is entropy

Answer 13

The universal tendency towards disorder

Question 14

Creating order from disorder requires inputs of…

Answer 14

…energy

Question 15

Chemical evolution

Answer 15

Inputs of energy lead to the formation of increasinly complex carbon contaning substances

Question 16

WOOHO

Answer 16

!!!!

Question 17

4 Macromolecules of life

Answer 17

Carbohydrates
Lipids
Proteins
Nucleic acids

Question 18

The macromolecules: DNA and RNA are polymers,
specifically nucleic acids, made up of many nucleotides

Answer 18

Deoxyribonucleotides for DNA
Ribonucleotides for RNA

Question 19

Nitrogenous bases

Answer 19

Molecules that help to make up nucleotides

Question 20

Which nitrogenous base is only found in RNA

Answer 20

Uracil found only in RNA, replaces thymine in RNA

Question 21

What are functional enzyme like 3d strands called

Answer 21

Ribozymes

Question 22

How are 3d rna strands formed

Answer 22

Long chains of RNA will fold back and basepair with themselves, forming 3-D structures, like proteins.

Question 23

Natural seelction of RNA sequences

Answer 23

1. There is variation in a
   population of RNA molecules.
2. RNAs that perform a
   particular job are more likely to
   be selected than others.
   Selected RNAs are promoted to
   reproduce more than others.
3. The population of RNA
   has evolved and now
   contains more useful
   molecules.

Question 24

A living thing must ___ to avoid decay and disorder

Answer 24

Work

Question 25

Why was RNA probably the original form of life ?

Answer 25

It serves as a template for its own reproduction.

Question 26

How does RNA reproduce

Answer 26

RNA has the feature of base complementarity. Nucleic acids form the backbone of the strand, and purines and pyrimidines selectively pair together via hydrogen bonds to create a complementary strand.

Question 27

What is the basic requirement for life

Answer 27

Reproduction

Question 28

What fundamental drive does the innate ability of RNA and DNA to replicate itself create in terms of natural selection, and how does this affect the prevalence of certain sequences?

Answer 28

The innate ability of RNA - and thus DNA – to replicate itself means that there is a fundamental drive for natural selection to favor those sequences which are most likely to reproduce themselves. The more capable a strand is of reproducing, the more there willbe of it!

Question 29

How does natural selection operate on individuals, and what is the impact on the gene pool for those who do not reproduce?

Answer 29

Individuals who do not reproduce drop out of the gene pool - biologically speaking, they contribute nothing to their species. Natural selection operates on the traits (phenotypes) of individuals; those individuals with the most successful phenotypes have the most offspring. Because traits are ultimately determined by an individual’s genes (DNA), natural selection promotes certain genotypes. More offspring = more DNA replication = life WIN!

Question 30

So what is the purpose of life

Answer 30

reproduction

Question 31

Fitness in relation to the purpose of life

Answer 31

The genetic contribution of an organism’s descendants to future generations. (e.g. number of surviving offspring). The “goal” of life is to produce as many healthy offspring as possible, and to equip them such that their likelihood of reproductive success is maximized as well. Fitness is only compared relative to individuals of the same species, and usually in the same population. So technically the purpose of life is: High Relative Fitness!

Question 32

High relative fitness =

Answer 32

having lots of babies (biologically speaking)

Question 33

# Asexual reproduction Binary fission

Answer 33

Single parent cell doubles its DNA, then divides into two cells. Usually occurs in bacteria.

Question 34

# Asexual reproduction Budding

Answer 34

Miniature adult grows on surface of parent breaks off, resulting in the formation of two individuals. Occurs in yeast and some animals

Question 35

# Asexual reproduction Fragmentation

Answer 35

Organisms break into two or more fragments that develop into a new individual. Occurs in many plants, as well as some animals

Question 36

# Asexual reproduction Parthenogenesis

Answer 36

An embryo develops from an unfertilized cell. Occurs in invertebrates, as well as in some fish, amohibians, and reptiless

Question 37

Explain sexual reproduction

Answer 37

Each parent contributes a gamete - a sex cell that has half of the normal DNA of a regular body cell. In males, the gametes are sperm and in females, the gametes are eggs. When these two gamete combine during fertilization, the result is a zygote, which then continues to develop into an embryo.

Question 38

Aseual reproduction is essentially..

Answer 38

cloning

Question 39

What is the original form of reproduction

Answer 39

Asexual reproduction

Question 40

NAme some positive things about asexual reproduction

Answer 40

100% of your genes passed! Why give up 50%?? Preserve successful genotypes! Don’t dilute with recombination and recessive traits! No mate required; don’t need others around

Question 41

NAme the problems of sexual reproduction

Answer 41

1) In a sexual population, half the individuals cannot technically reproduce – the males! 2) All offspring inherit only 50% of each parent’s DNA

Question 42

When did life begin | explanation

Answer 42

Life began the moment molecules of information began to reproduce and evolve by natural selection

Question 43

4 Requirements for life

Answer 43

1. A living thing must work to avoid decay and disorder. 2. To do that, a living thing must have or create a closed system (a cell) 3. They have some molecule that can carry information. 4. This information must evolve by natural selection