Cells

Question 1

What is the function of histones?

Answer 1

Helps support and protect DNA

Question 2

Heterochromatin vs Euchromatin

Answer 2

Densely packed vs not densely packed

Question 3

What is the function of the nucleolus?

Answer 3

Contains DNA -> rRna- makes ribosomes essential in the process of protein synth

Question 4

What does DNA code for?

Answer 4

Codes for protein synthesis in cytoplasm. Isolates chr from the rest of cytoplasm protects DNA

Question 5

What is achieved by presence of nuclear pores?

Answer 5

DNA code for prot synth taken from safety of nucleus to cytoplasm where it takes place

Question 6

What is found on the outer membr of nuclear env?

Answer 6

Encrusted w ribosomes and is site of orig for RER

Question 7

What carries gen code from DNA and how does it pass thru nuclear pores?

Answer 7

mRNA- passes thru nuclear pores to cytoplasm

Question 8

What is the function of the RER?

Answer 8

Provides scaffolding for ribosomes to make prot and ER operates as distr network for proteins

Question 9

What facilitates the transp of mRNA?

Answer 9

ER is joined with nuclear env fac transp of mRNA which carries gen code from nucl to ribosomes

Question 10

What is the function of SER?

Answer 10

Synth of lipids e/g phospholipids

Question 11

What are the 2 poss locations of ribosomes?

Answer 11

Free in cytoplasm/ attached outer surf of ER

Question 12

What does each ribosome have?

Answer 12

Each one has a large and small sub-unit made of protein and rRNA

Question 13

What is the G.A?

Answer 13

Series of curved flattened sacs (cisternae)

Question 14

What do the vesicles in Golgi body do?

Answer 14

Vesicles containing newly synth proteins pinch off from RER and coalesce with forming convex edge of syst- usually edge closest to nucleus

Question 15

How may proteins be mod in G. body?

Answer 15

May have carb added to form glycoprot
Lipids may be added to form lipoprot
May have prosthetic group/ cofactors added
Dif pp joined together to form protein w quaternary str
They can be labelled packaged or sorted

Question 16

What happens to vesicle once prot is modified?

Answer 16

Vesicles cont final protein are pinched ff from maturing concave face (usually side furthest away from nucleus)

Question 17

What is the function of the final vesicles?

Answer 17

Transp protein either within cell/ fuse with cell surf membr to release contents outside the cell

Question 18

What are lysosomes?

Answer 18

Tiny vesicles, formed by GA

Question 19

What do lysosomes contain and what do these do?

Answer 19

Hydrolytic enzymes fuse with other vesicles in cell that cont something to be destroyed/ digested e.g cell debris

Question 20

Why do lysosomes have an important role in phagocytes>

Answer 20

They digest engulfed bacteria enclosed in a phagosome

Question 21

How are mitochondria enclosed?

Answer 21

In double membr

Question 22

How is mitochond inner membr folded?

Answer 22

Folded to form cristae that extend into matrix of mit

Question 23

What do cristae do?

Answer 23

Increase sa which increases no. enzymes that can be embedded within the membr

Question 24

What is the function of the mitochondria?

Answer 24

Site of ATP synth during aerobic resp

Question 25

How are the cristae dif in more active cells>

Answer 25

More of them and they are more deeply folded

Question 26

What are microtubules?

Answer 26

Hollow cylinder fibres formed from tubulin that form cytoskeleton

Question 27

What is function of spindle fibres?

Answer 27

imp in movement of chr during mitosis and meiosis and are formed of microtubules

Question 28

What is the function of the centrioles?

Answer 28

Inv in assmbley of spindle fibres during cell div formed of microtubules and also important constit of cilia and flagella

Question 29

What do animal cells not have that plant cells do?

Answer 29

Lysosomes and Centrioles

Question 30

What is the plant cell wall made up of?

Answer 30

Made up of polysacc cellulose which is laid down as microfibrils- consists of many cel mol cross linked to each other

Question 31

Describe the primary c.w

Answer 31

Many microfibrils orientated in dif and random dir Rel loose arrangement of microfib allows c.w to expand as cell grows

Question 32

Descr sec cell wall

Answer 32

When cell reaches full size, add layers of cel can be dep to form sec c.w In sec cw each layer of microfib or in same dir However, add layers or in dif dir to other layers

Question 33

What is the middle lamella?

Answer 33

Cell walls of adj cells linked by middle lamella- largely made up of polysacc pectin

Question 34

How does calcium pectin work?

Answer 34

Forms a gel/cement that acts as an adhesive and holds neighbouring cells together

Question 34

What are plasmodesmata?

Answer 34

Strands of cytoplasm that ext between neighbouring plant cells

Question 35

What is the function of plasmodesmata?

Answer 35

Prov gap in cw of adj cells that enable dif kinds of mol to pass thru

Question 36

What are chloroplasts surrounded by?

Answer 36

Surr by double membr/env which encloses stroma

Question 37

What is found within stroma? What is found within these?

Answer 37

Thylakoids- arranged in stacks called grana Contain chlorophyll

Question 38

What is function of chloroplasts?

Answer 38

Site of phs- located in palisade cell of leaves

Question 39

What is cell wall of fungal cells made of?

Answer 39

Made of glycoprotein chitin

Question 40

What acts as storage in fungal cells?

Answer 40

Glycogen

Question 41

What do fungal cells have in common w animal cells?

Answer 41

SER,RER, nucl, vac, gly, granules and mitochondria

Question 42

What do all viruses have in common?

Answer 42

They all have a protein coat (caspid) that surrounds nucleic acid- DNA/ RNA

Question 43

How are bacteriophage proteins formed?

Answer 43

Inside host cells viral DNA codes for prod of new proteins for new protein coats DNA itself replicates to make copies then packaged within protein coats, forming new viruses Bact cells destroyed and ruptures and many new viruses released to cont cycle

Question 44

Descr the structure of HIV:

Answer 44

RNA core and typical protein coat and lipid bilayer containing glycoprotein

Question 45

What do HIV viruses deliver?

Answer 45

Deliver RNA to host cell together with enzyme reverse transcriptase

Question 46

What is the function of reverse transcriptase?

Answer 46

Catalyses synth of DNA from RNA

Question 47

How does DNA make new viruses in HIV?

Answer 47

Synth new protein coats and viral RNA

Question 48

Why are retroviruses known as retroviruses?

Answer 48

Viral RNA used as template to make DNA. This is reverse of normal transcr. process where DNA is used to make mRNA as protein synth

Question 49

In humans what does HIV invade?

Answer 49

Invades a type of lymphocyte called helper T cells

Question 50

What happens as more T cells destroyed?

Answer 50

Immune syst crit compr- AIDS

Question 51

Why are viruses not true cells?

Answer 51

NO cytoplasm or organelles assoc w it Viruses inert unless they gain access to a living cell

Question 52

What are the sim in HIV and Bact?

Answer 52

Both v. small and non-cellular Contains genetic material within a protein coat

Question 53

What are the dif between HIV and Bact?

Answer 53

Dif shape and phages have tail fibres attached to a base plate- Tail fibres imp in attaching virus to bact plates In HIV protein coat/ head is within a phospholipid bilayer (no lipid bilayer in phages) Glycoprotein present in HIV, not phages Bacteriophages normally cont DNA vs HIV: RNA HIV cont reverse transcriptase (norm not in phages)