Topic 3: cellular level of organization

Question 1

what is the cell?

Answer 1

-basic structural and functional unit of the body
-can perform all basic life functions

Question 2

what are the names of the outermost part of the cell?

Answer 2

-cell membrane
-plasma mebrane
-plasmalemma

Question 3

what is the cell membrane composed of?

Answer 3

-phospholipid bilayer
-cholesterol
-membrane proteins
-membrane carbohydrates
-microvilli

Question 4

what does the phospholipid bilayer divide?

Answer 4

-the intracellular fluid and the extracellular fluid

Question 5

what is intracellular fluid?

Answer 5

-fluid inside the cell

Question 6

what is extracellular fluid

Answer 6

-fluid outside the cell

Question 7

what are the two types of membrane proteins?

Answer 7

-integral proteins
-peripheral proteins

Question 8

what are integral proteins?

Answer 8

-integrated within the membrane
-they have a hydrophobic region to interact with the fatty acid tails
-those that extend across the entire membrane are called transmembrane proteins

Question 9

what are peripheral proteins?

Answer 9

-attached to the surface of the membrane
-also can be attached to the surface of an integral protein

Question 10

what are the functions of membrane proteins?

Answer 10

-enzymes
-transporters (ATP)
-channels (NO ATP)
-receptors (HORMONES)
-anchors
-identity markers (for the immune system)

Question 11

what are membrane carbohydrates?

Answer 11

-only on the outer surface
-bound to other proteins (glycoproteins) or lipids (glycolipids)
-used for cell recognition (sperm recognizing an egg)
-anchor cells together

Question 12

what is cholesterols purpose in the membrane?

Answer 12

-they are scattered throughout the membrane
-add stability + fluidity
-doesn’t break apart at extreme temps

Question 13

what is the phospholipid bilayer composed of?

Answer 13

-phosphate head group (hydrophilic)
-fatty acid tails (hydrophobic)
-double layered
-heads on the outer side, tails on the inner

Question 14

what are microvilli?

Answer 14

-small projections of the cell membrane
-used to increase surface area (increased absorption)
they are best seem on small intestine cells and kidney cells

Question 15

what is the fluid mosaic model?

Answer 15

-shows the phospholipid bilayer
-shows membrane proteins
-fluid - components can move (phospholipids + some proteins)
-mosaic - proteins dot the surface

Question 16

what is the cytoplasm?

Answer 16

• an AREA (not a fluid)
  -area between the inside of the cell membrane and the outside of the nucleus

Question 17

what are the two divisions of the cytoplasm?

Answer 17

-cytosol
-organelles

Question 18

what is cytosol?

Answer 18

-a gel-like fluid
-contains water, ions (K+, Na+), suspensions of carbohydrates, proteins, and lipids
-can have inclusions (melanin or glycogen)

Question 19

what are organelles?

Answer 19

-structures that perform specific functions
-essential for life
-can be non-membranous (direct contact with cytosol)
-can be membranous (isolated from cytosol)

Question 20

what are non-membranous organelles?

Answer 20

-ribosomes
-centrosome
-cytoskeleton

Question 21

what are ribosomes?

Answer 21

-sites for protein synthesis
-contain rRNA (ribosomal RNA) and proteins
-can be free in cytosol
-can be attached to endoplasmic reticulum

Question 22

where are proteins destined depending on the location of ribosomes?

Answer 22

-free (destined for cytosol, mitochondria, or nucleus)
-ER (destined for all other sites)

Question 23

what are the two components of centrosomes?

Answer 23

-a pair of centrioles (perpendicular)
-the pericentriolar matrix

Question 24

what are the functions of centrosomes

Answer 24

-organizing centers for microtubules
-spindle apparatus for cell division
-organizes the cytoskeleton

Question 25

what is the cytoskeleton?

Answer 25

-3 types of cytoskelton -they all support cell shape (structural) -formed from proteins -important in cell movement, cell division, movement/anchoring of organelles + proteins (receptors + enzymes)

Question 26

what are the 3 types of cytoskeleton?

Answer 26

-microfilaments -intermediate filaments -microtubules

Question 27

what are microfilaments made of? what are their functions?

Answer 27

-made of actin -muscle contraction (done with help of myosin) -cell locomotion -cytokinesis

Question 28

what are intermediate filaments made of? what is their function?

Answer 28

-composition is tissue specific (ex: keratin) -supports the cytoplasm -structural support for cell attachment and tissue development (scaffolding for the cell)

Question 29

what are microtubules made of? what is their function?

Answer 29

-hollow tubes made of tubulin -form centrioles, spindle apparatus, cilia, and flagella -structural -move or secure organelles in place

Question 30

what are membranous organelles?

Answer 30

-mitochondria -endoplasmic reticulum -golgi apparatus/complex -lysosomes -nucleus

Question 31

what is the mitochondria?

Answer 31

-site of ATP synthesis -contains its own DNA, RNA, and proteins -has a double membrane

Question 32

what is the endoplasmic reticulum?

Answer 32

-membranous network throughout the cytoplasm -two types -rough ER -smooth ER

Question 33

what is the rough ER?

Answer 33

-has ribosomes attached -site of the synthesis of secretory, lysosomal, and membrane proteins

Question 34

what is the smooth ER?

Answer 34

-lacks attached ribosomes -continuous with the rough ER -synthesizes lipids and steroid hormones

Question 35

what is the golgi complex?

Answer 35

-stacks of mebrane discs -modifies proteins (trims or adds carbs and lipids) -sorts, packages, and delivers proteins -delivers to the cell membrane, lysosomes, or for secretion

Question 36

what are lysosomes?

Answer 36

-filled with digestive enzymes -digest bacteria, viruses, worn out organelles -clean up function

Question 37

what is the nucleus?

Answer 37

-the largest membranous organelle -cell control center -cells can have more than one

Question 38

what are the different parts of the nucleus?

Answer 38

-nuclear envelope -nucleolus -chromosomes/chromatids

Question 39

what is the nuclear envelope?

Answer 39

-a double membrane with nuclear pores -cytoplasm connection -connected to ER

Question 40

what is the nucleolus

Answer 40

-non-membranous -dense region of DNA, RNA, + proteins (less light) -where ribosomes are made and assembled

Question 41

what are chromosomes?chromatids?

Answer 41

-contains DNA + histone proteins -can either be dispersed (chromatin) -can be condensed + individually visible

Question 42

what is chromatin?

Answer 42

-uncoiled DNA -not individually visible -in this form most of the time (when the cell is not dividing)

Question 43

where are condensed chromosomes found?

Answer 43

-in dividing cells

Question 44

what are the 3 principle parts of the cell?

Answer 44

-nucleus -cytoplasm -plasma membrane