Unit 2 part 2 (the cell) Flashcards Preview

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Flashcards in Unit 2 part 2 (the cell) Deck (48):
1

All Cells Contain certain features

-bounded by plasma membrane
- contain cytosol
-chromosomes
-ribosomes

2

Eukaryotic vs. Prokaryotic cells

Eukaryotic:
- most of DNA is contained in the nucleus
-contain organelles
-larger
Prokaryotic:
- DNA concentrated in nucleoid, a non-membrane bound region
-smaller

3

cytosol

a jellylike substance in which subcellular components are suspended

4

ration of surface area to volume in cells

-critical
-for each section of membrane, only a limited amount of a particular substance can cross per second
-smaller objects have a greater ratio
-need for surface area large enough for volume explains microscopic size and oval like shapes of some cells

5

microvilli

long thin projections from the surface of a cell which increase surface area

6

nucleus

contains most of the genes in a eukaryotic cell
-directs protein synthesis by synthesizing messenger RNA according to DNA instructions

7

nuclear envelope

a lipid bilayer membrane, perforated by pores that surrounds the nucleus

8

pore complex

lines each pore in the nuclear envelope, regulates passage of proteins, RNA, and macromolecules

9

nuclear lamina

lines the nuclear side of the envelope
-net of protein filaments that maintains the shape of the nucleus by mechanically supporting the envelope
- may help organize genetic material

10

chromosomes

structures that carry genetic info. Each contains one DNA molecule wrapped around associated proteins

11

chromatin

the complex of DNA and proteins making up chromosomes
-chromosomes cannot be distinguished when cell is not dividing

12

nucleolus:

mass of densely stained granules and fibers in the nucleus
-location where ribosomal RNA is synthesized
-proteins are assembled with rRNA into large and small subunits of ribosomes
-exit into cytoplasm and combine

13

Ribosomes

complexes made of rRNA and protein that carry out protein synthesis

14

free ribosomes

suspended in cytosol, proteins function within cytosol, intended for cells own use

15

bound ribosomes

attached to ER or nuclear envelope.
-produce proteins bound for insertion into membranes, packaging into organelles, or usually export from the cell

16

endomembrane system

includes the nuclear envelope, ER, Golgi apparatus, lysosomes, vesicles and vacuoles, and the plasma membrane
-carries out synthesis and transport of proteins, metabolism, movement of lipids, and detoxification of poisons

17

Endoplasmic Reticulum:

consists of a network of membranous tubules and sacs called cisternae
-ER membrane separates internal compertment(lumen or cisternal space) from cytosol

18

smooth ER

outer surface lacks ribosomes
- may function in synthesis of lipids, metabolism of carbs, detoxification of poisons, and storage of calcium ions
-produces steroids in animal cells
-detoxification involves adding hydroxyl to a group so it is more soluable
- stored calcium can trigger responses, such as muscle contraction

19

Rough ER

studded with ribosomes on outer surface
- ribosomes produce secretary proteins
-depart from ER in transport vesicles that bubble out of the transitional ER
- membrane factory for the cell; Adds membrane proteins and phospholipids to its own membrane and portions of it are transferred as transport vesicles to other compartments of the endomembrane system

20

The Golgi Apparatus

-products of ER are modified and stores and then sent to their destinations
-consists of membranous sacks
-membranes of cisternae on opposite sides of the stack differ in thickness and composition
-proteins modified as the pass from cis to trans face
-sorts products, phosphate groups added to products act as ZIP codes or transport vesicles may have membranes that recognize certain docking points

21

cis face of Golgi

-near ER, receiving part of Golgi

22

trans face of Golgi

-shipping, gives rise to vesicles that travel to other sites

23

cisternal maturation model

says that cisternae of the Golgi progress forward from the cis to trans face, carrying and modifying cargo as they go

24

Lysosome

a membranous sac of hydrolytic enzymes that an animal cell uses to digest macromolecules
-hydrolytic enzymes and lysosome are made by Rough ER then transferred to Golfi

25

Phagocytosis

Food vacuoles engulf smaller organisms and then fuse with lysosome whose enzymes digest the food
-digestion products pass into cytosol and are used as nutrients for the cell

26

autophagy

Lysosomes recycle the cells own organic material
-damaged organelle becomes surrounded by a double membrane
-lysosome fuses with outer membrane of the vesicle, enzymes dismantle enclosed material which are returned to cytosol for reuse
-allows cell to continually renew itself

27

Vacuoles

large vesicles derived from the ER and the Golgi
-used for storage
-in plants, can hold reserves of organic compounds, poisons, or pigments

28

Food vacuoles

formed by phagocytosis of microorganisms to be used as food for the cell

29

contractile vesicles

pump excess water out of the cells, maintaining a suitable concentration of ions and molecules

30

Central vacuole

found in mature plant cells
-contain cell sap- the plant cells main repository of inorganic ions
-enlarges cell as it absorbs water

31

mitochondria

the sites of cellular respiration, the metabolic process that uses oxygen to generate ATP by extracting energy from fuels
-cells can contain hundreds, more active the cell, the more mitochondria
-move around, change shape, and divide

32

Structure of mitochondria

enclosed by two membranes- outer is smooth, inner has infoldings called cristae which give this membrane a large surface area
-intermembrane space; the narrow region between the inner and outer membrane
mitochondrial matrix: contains many different enzymes as well as DNA and ribosomes

33

Chloroplasts

-contain chlorophyll and function in the photosynthetic production of sugar
--move around, change shape, and divide

34

thylakoids

a membrane system within the chloroplast
-in some regions, stacked like poker chips
-each stack is called a granum

35

Stroma

in the chloroplast, fluid outside the thylakoids which contains the chloroplast DNA and ribosomes and enzymes

36

plastids

a family of closely related plant organelles

37

Peroxisome

a specialized metabolic compartment bounded by a single membrane
-contain enzymes that transfer H atoms from various substrates to oxygen creating H2O2
-some use oxygen to break down fatty acids and convert H2O2 to water

38

glyoxysomes

found in fat-storing tissue of plant seeds.
-convert fatty acids to sugar, which is used for energy by the seedling

39

Cytoskeleton

a network of fibers that organizes structures and activities in the cell

40

Roles of the Cytoskeleton

-gives mechanical support to cell and maintains its shape (stabilized by a balance between opposing forces exerted by elements)
-provides anchorage for organelles and molecules
-several types of cell motility involve the cytoskeleton (ex. reacts with motor proteins)
-manipulates plasma membrane- bends it inward to create vesicles

41

microtubles

hollow rods measuring w=25nm and l=200nm-25um
-made up of tubulin, each tubulin dimer is made up of 2 slightly different polypeptides
-grow by adding tubular dimers
-two ends are slightly different
-shape and support cell, serve as tracks

42

Centrosomes

a region often located near the nucleus which grows and organizes microtubles

43

Centrioles

located within the centrosome, composed of nine sets of triplet microtubles arranged in a ring
-replicate before animal cells divide

44

microfilaments

aka actin filaments
-role is to bear tension
-3D network formed by microfilaments just inside the plasma membrane supports cell structure and gives cortex( outer cytoplasmic layer) a semisolid consistency
-part of a contractile apparatus in muscle cells

45

psuedopodia

cellular extensions that help an amoeba to pull itself forwards

46

cytoplasmic streaming

a circular flow of cytoplasm within cells; speeding the distribution of material within the cell

47

Intermediate filaments

larger than microfilaments but smaller than microtubules
-diverse and specialized for bearing tension
-more permanent, especially sturdy, play an important role in reinforcing the shape of the cell

48

actin filaments and muscle cell contraction

-myosin filament projections walk along microfilaments, shortening the cell
-similar process used to pinch dividing animal cell into two and helps amoeba motility