HL Bio Unit 2 - Cells

what are the 8 characteristics of living things

1. metabolism

2. growth

3. reproduction

4. response and sense

5. excretion

6. homeostasis (maintain internal balance)

7. nutrition

8. movement

prokaryotic cells

• unicellular

• no nucleus

• no membrane-enclosed organelles genetic infp

what are the small 2 prokaryotic cells called

eubacteria and archaea

where do prokaryotic cells live

diverse environment

what is cell theory

all living things are made up of one or more cells, cells are the basic units of life and all cells come from pre-existing cells

whats the 4 common characteristics of cells

1. surrounded by membrae, separates them from external

2. store genetic info for regulating cell activity/metabolism

3. many reactions are catalyzed by enzymes

4. have own energy release sytem that power all activites

why is aseptate hyphae atypical

atypical cell - fungi

• septum divides cells

why are phloem sieve tube elements atypical

n plants
- no nuclei, but surrounded by other cells with all regular divisions and parts

why are multinucleated muscle cells atypical

no divisions between cell, many nuclei instead

why are red blood cells atypical

no nucleus

how does DNA work in prokaryotic cells

1. circular

2. not contained by nucleus

3. not associated with proteins

4. may be found in plasmids

how many chromosomes does a prokaryotic cell genome have

single

type of reproduction in prokaryotic cells

• binary fission (very fast asexual reproduction

• daughter cells are genetically identical

what type of ribosomes in prokaryotes vs eukaryotes

70S vs 80S

are prokaryotic cells anaerobic or aerobic

may be anaerobic

what may a prokaryote cell have that is outside the cell membrane, a different carb from cellulose of plant cell wal

extracellular cell wall containing peptidoglycan

what may help prokaryotic cells attach/communicate with other bacteria

flagella or pili

what may prokaryotic cells have to provide protection and prevent water loss

enclosed with a capsule

what are eukaryotic cells

• mutli or unicellular organisms

• nuclei

• membrane bound organelles

cytoplasm is _________ into membrane bound orgganelles so materials are concentrated in one location

compartmentalized

compare DNA in prokaryotes vs eukaryotes

1. DNA is naked vs DNA bound to protein

2. DNA is circular vs DNA is linear

3. no introns vs introns

compare organelles in prokaryotes vs eukaryotes

1. no nucleus vs nucleus

2. no membrane bound vs membrane bound

3. 70s ribosomes vs 80s

compare reproducton in prokaryotes and eukaryotes

1. binary fission vs mitosis and meiosis

2. single chromosome (haploid) vs chromosomes paired (diploid)

compare average size for prokaryotes to eukrayotes

smaller (1-5 um) to larger (10-100um)

what stops bacteria from building/repariing cell walls ande making RNA/DNA/proteins

antibacterial agents

some antibiotics ____ bacteria, other ____ bacterial growth

kill, inhibit

why should antibiotics be used in moderation

so bacteria doesn’t evolve to many resistant strains, OBSOLETE

what does the mitochondria and chloroplasts originate as

aerobic and photosynthetic prokaryotes

if cell wall is present it may be ….

thin walled (gram -ve) vs thick walled (gram +ve)

3 functions of an extracellular matrix

1. supports and anchors cells

2. separates tissues

3. participates in cell signalling and communication

cytoplasm

• all organelles in it

• mainly WATER

• chemcial reactions take place inside

cytosol

fluid material between cell membrane and nucleus - in cytoplasm

cell membrane (semi-permeable membrane)

• surrounded by flexible double layered cell membrane, supporting and regulation of entry

nucleus (4)

• control centre

• contains DNA nad hereditary material

• RNA transcribed here

• consists of nuclear envelope, chromatin, nucleolus

nuclear membrane/envelop (2)

• double membrane that surrounds the nucleus

  • contains pores that allow passage of material in and out of nucleus

nucleolous 3

• densely packed ball of DNA, RNA and protein

• visible in cell only when cell not dividing

• used to make ribosomes

chromatin 3

• long, thread-like strands of DNA

• thicken, and coil into choromsomes during cell division

• set number in each species

centrioles 5

• pair of cylindrical organelles found near nucleus

• 9 tubes, 3 microtubules in each

• cylinders right angles to each other

• needed for spindle fibers in cell division

• found in animals

chloroplasts 4

• plastids

• found in plant and algae

• green pigment chlorophyll

• converts energy from sun into stored form of chemical energy called glucose

endoplasmic reticulum 4

• 3d network of tubles and one continous membrane

• can be rough with ribosomes or smooth

• serves as cells transportation

• stores substances, mainyl proteins

golgi body/complex 3

• stack of flattened sacs

• made of series of double membranes

• responsible for packaging proteins for storage or export out the cell

lysosomes 4

• membrane bound sacs

• enzymes to break down molcules (proteins, lipids or carbs)

• transport undigested material to cell membrane for excretion

• can cause cell to break if broken because enzymes release and digest cell

ribosomes 3

• small, spherical organelles - free,floating or attached to ER

• 25% mass of cell

• responsible for manufacture of proteins

vacuoles 2

• membrane bound sacs used for storage, digestion and waste removal

• most plants only have one large vacuole

vesicles 2

• membrane bound sacs for transporting materials

• animal cells have small vesicles

microtubules 3

• different length

• makes spindle fibers in cell division

• makes cilia and flagella in unicellular

mitochondrion 2

• powerhouse

• double membrane structure converting glucose into cellular energy (ATP)

endomembrane systems

organelles that form a continous system to transport material through cell

list order of endomembrane system

nucleus → ER → vesicles → Golgi → plasma membrane

list 7 characteristics of animal cells

1. no plastids or cell wall

2. small vacuoles for water or nutrients

3. centrioles control spindle fibres during mitosis

4. cilia flagella present in many cells

5. single cells sometimes in a chain

6. small size less than 5um

7. often rod shape, spheroidal, helical

list 6 characteristics of plant cells

1. contains plastids (chloroplsats, amyloplasts)

2. cells walls composed of cellulose

3. large central vecuole to store water and maintain pressure

4. no centroiles or cilia/flagella only some male gametes

5. large size more than 5um

6. shape with regular flat sides and cell junctions easily visible

list the 6 characteristics of fungi cells

1. no plastids

2. cells walls composed of chitin (polysaccharide)

3. large central vacuole store water and main pressuer

4. no centroiles or cilia/flagela (except some male gametesO

5. more than 5 um

6. tends to be rounded with junctions between cells hard to see

endosymbiosis

theory that mitochondria and chloroplasts originated as aerobic and photosynthetic prokaryotes

endocytosis

chloroplasts, prokaryotic photosynthetic cell engulfed action

what is the evidence for endosymbiosis 4

• double membrane (inner, prokaryotic like)

• naked, circular DNA inherited and transcribed indepndent of host cell

• 70S ribosomes

• reproduce similar to binary fission

4 points of differential centrifugation

1. spin around quickly

2. separates by size/density

3. heavy particles form pellets

4. lightest stays in solution

Why is the nucleus compartmentalized in eukaryotic cells but not in prokaryotic cells? 3

1. RNA must leave nucleus before protein synthesis

2. post transcriptional modification can occur (DNA → RNA)

3. complete RNA before protein made

Why is cytoplasm compartmentalized in eukaryotic cells? 5

• concentration of enzymes and substrates

• separation of wastes (lysosomes or phagocytic vacuoles)

• regulation of phH

• movement of materials

• more membrane surface areas

Why is the nucleus a double membrane?  3

• double membrane allows for larger pores

• proteins from cytoplasm can move into nucleus

• RNA and ribosomes made in nucleus can move into cytoplasm

size of viruses

20-300 um

what do viruses consist of

nucleic acid core (DNA/RNA) with a protein coat (capsid)

what is capsid composed of

repeating protein subunits giving viruses symmetrical shape

some viruses are surrounded by ______

envelope

budding

the thing of getting an envelope from host cell

exocytosis

using host cell vesicles to release viruse

5 points on viruses being non living

1. not made of cells

2. cannot reproduce on their own

3. do not make energy or waste

4. do not grow

5. contain few or no enzymes

why do we predict many different origins of virsues 4

• no common ancestor

• large diversity in shape and structure

• large variety in genetic material

• DNA/RNA, ds/ss, circular/linear, varibale length and # of genes

progressive hypothesis viruses

evolved from modified cell components e

regressive virus hypothesis

viruses developed through loss of cell components, could be result of CONVERGENT evolution

virus first hypothesis

viruses evolved before cells

what is the lytic cycle do

infects bacteria like bacteriophage lambda

list the 5 steps of lytic cycle

1. attachment

2. entry

3. replication

4. assembly

5. lysis and release

what happens in step 1 of lytic cycle

attachment : virus into bacteria

what happens in stage 2 of lytic cycle

entry: genetic material deposited into host cell

what happens in stage 3 of lytic cycle

replication: replicates genetic material + protein synthesis assembly

what happens stage 5 of lytic cycle

lysis and release: host cells ruptures after making viral proteins

obligate parasites

viruses must have host cells to survive

what does the lysogenic cycle use to incorporate viral genetic material into host’s DNA

integrase enzyme

what happens when the host cells replicates

the viral DNA replicates

what will the DNA in lysogenic cycle start to do

be more active and lytic cycle will start

what can start evolution in bacteria in the lysogenic cycle

viral DNA can contain genes from previous host cell

note about viral proteins in lysogenic cycle

it doesnt make them right away

an example of housekeeping genes

respiration tumor suppressor

specialized cells express only _____

the genes they need

fertilization

fusion of male and female (sperm &egg)

gene expression control what

which genes act in a cell and which proteins are produced

how many different human cells are there?

220

What does cell specialization do with certain genes in certain cells?

“switching on”

what do regulatory chemicals or morphogens control?

gene expression

what does the cell position in the embryo resulted?

receiving diff signals

what does closer to the source mean on a gradient scale?

higher amount of molecule

What can molecules or chemicals bond to turn on or off transcription?

proteins in cell/nucleus

stem cells

and differentiated cells that can divide repeatedly

Stem cells may be … (2)

• un differentiated (any type of cell)

• partially differentiated(some types of cells)

Embryonic stem cells are…

undifferentiated

adult stem cells are…

partially differentiated

Induced pluripotent cells are

differentiate into undifferentiated cell

what is the order of potent cells?

1. totipotent (become any type)

2. pluripotent (more specialized)

3. multipotent (only a few)

4. unipotent (only one)

Stem cell niche

precise location of stem cells within a tissue

What must stem cell niche allow for?

to remain in active and undifferentiated, but proliferate and specialized when required