Lec 40

Question 1

Descent of organisms from ——— with development of genetic and phenotypic changes overtime make them more —— to the environment

Answer 1

Common ancestors

suited

Question 2

unity of the universe :

Answer 2

living things share common characteristics because they have a common ancestry

Question 3

diversity of the universe

Answer 3

living things are diverse because each species is adapted to its habitat and way of life

Question 4

Very simple cells were produced through 4 main stages

Answer 4

1- abiotic (nonliving) synthesis of small organic molecules
2-joining of monomers into organic polymers { proteins & nucleic acids }
3- packaging of molecules into protobionts
4- protobionts acquired ability to self replicate & other cellular properties which made inheritance possible
[ cells were prokaryotic ]

Question 5

What are organic monomers

Answer 5

{amino acids & nucleotides}

Question 6

What are protobionts

Answer 6

droplets with membranes that maintained and internal chemistry different from their surroundings

Question 7

• the oldest fossils of a eukaryotic organisms about —— billion years old
• scientist relate the emergence of eukaryotes to ——— that made earth a possible place for existence of true organisms
• early eukaryotic cells have a ——— and can ——— enabling them to surround and engulf other cells

Answer 7

2.1
oxygen revolution
cytoskeleton , change shape

Question 8

the first eukaryotes may have been ——— of other cells
Through ——— eukaryotes engulfed ————— , ( chloroplast and related organisms ) which were small prokaryotes ( Endosymbionts )

Answer 8

predators
Endosymbiosis , mitochondria and plastids

Question 9

What are endosymbiont

Answer 9

cell that lives within another cell (host cell)

Question 10

• prokaryotic ancestors of mitochondria and plastids gained entry to host cells as ————
• in all cases , symbiosis became very ———

Answer 10

undigested preys
beneficial

Question 11

ancestors of mitochondria were ———

Answer 11

aerobic heterotrophic prokaryotes

Question 12

Ancestors of plastids were

Answer 12

photosynthetic prokaryotes

Question 13

A heterotrophic host will benefit from nutrients released by ———— Endosymbionts
A cell which was anaerobe would benefit from —— endosymbiont that turned the oxygen beneficial to advantage.

Answer 13

photosynthetic
aerobic

Question 14

The inner membranes of both organisms have —— and —— systems that are —— to those found in plasma membranes of living prokaryotes

Answer 14

enzymes , transport , homologous

Question 15

mitochondria and plastids replicate by —— process ( binary fission )

Answer 15

splitting

Question 16

each organelle contains a ——— DNA molecule

Answer 16

single circular

Question 17

organelles contain —— & —— to transcribe and translate their DNA into proteins

Answer 17

tRNA
ribosomes

Question 18

ribosomes inside these organelles are more similar to —— ribosomes

Answer 18

prokaryotic

Question 19

• Molecular studies indicate that a group of bacteria ( ———- ) are closest relatives of mitochondria
• Cyanobacteria are closest relatives to ——
  —— cell is considered as a chimera

Answer 19

alpha Proteobacteria
plastids
eukaryotic

Question 20

What is chimera ?

Answer 20

parts from different animals joined together

Question 21

the oldest known fossils of multicellular eukaryotes are ——— that lived —— years ago
the first multicellular organisms were ——

Answer 21

Small algae , 1.2 billion
colonies

Question 22

What are colonies

Answer 22

collections of cells replicating autonomously

Question 23

cell differentiation occurred when?

Answer 23

some cells in the colonies became specialised for different functions

Question 24

Multicellularity evolved several times among early——- giving rise to several lines of ——, plants , fungi and ——.

Answer 24

eukaryotes
algae
animals

Question 25

It is believed that ——— and other ———— coated terrestrial surfaces over billion years ago microscopic life in forms of plants , fungi and animals did not colonise land until ———— during early palezoic era

Answer 25

cyanobacteria , photosynthetic prokaryotes 500 million years ago

Question 26

- plants colonised land in the company of —— - roots of most plants are associated with —— - root fungi obtain their organic nutrients from —— (symbiosis)

Answer 26

fungi fungi plants

Question 27

- the most widespread and diverse land animals are ——— ( insects and spiders ) followed by ——— ( amphibians , reptiles , birds, mammals) - Terrestrial vertebrates developed into —— ( 4 limbs ) that distinguish them from —— vertebrates - Tetrapods include ——

Answer 27

arthropods , vertebrates tetrapods , aquatic humans

Question 28

- before 1969 all organisms were classified under———— , animals and plants - all organisms, including unicellular which possess chloroplast were considered under —— kingdom. - Cyanobacteria were considered —— - fungi were considered as —— because they are unable to move although they are ——— - unicellular protozoans that move and ingest their food were considered ——

Answer 28

two main kingdoms plant plants plants not photosynthetic animals

Question 29

in 1969 whittaker’s — kingdom system was applied , which prevailed in biology for — years

Answer 29

five , 20

Question 30

What are the whittaker’s kingdoms ?

Answer 30

Monera , protista , plantae , fungi , anemelia

Question 31

- currently biologist favour —— domain system ( bacteria , archaea , eukarya )which are considered as —— - bacteria and archaea differ in many key ( ————— ) characteristics - The kingdom —— no more exists

Answer 31

3 , superkingdoms structural , Biochemical , physiological monera

Question 32

the first cell ( Luca ) was —— then differentiated into bacteria and archaea

Answer 32

prokaryotic

Question 33

—— gave rise to eukarya which was a hunter cell

Answer 33

Archaea

Question 34

bacteria kingdom gave rise to aerobic bacteria (——) which was digested by —— and became a ——— protist

Answer 34

mitochondria eukarya heterotrophic

Question 35

The bacteria kingdom also gave rise to —— bacteria (chloroplasts) which were digested by ——— and became ———

Answer 35

photosynthetic heterotrophic protist photosynthetic protists