2 - Cells As Functional Units

Question 1

WHat does cell theory state

Answer 1

• Cells are the fundamental units of life.
  – All organisms are composed of cells.
  – All cells come from pre-existing cells.

Question 2

First cell described by

Answer 2

Robert Hooke
Dead cell walls of cork

Question 3

First LIVE cell

Answer 3

Anton van leeuwenhoek
Saw bacteria when looking at algae

Question 4

What is cell size limited by

Answer 4

SA:V
V = how much chemical activity carries out per unit of
time
SA = amount of a substance that can be taken in and how much waste released into the envir

Question 5

Difference between pro and eukaryotic cells

Answer 5

Pro = no nucleus or other membrane-bound compartments. Lack istinct organelles
Euk = have a membrane-enclosed nucleus and other membrane-enclosed compartments
and organelles

Question 6

What are Mycoplasma describe

Answer 6

Bacteria that lack a cell wall
* unaffected by some antibiotics such as penicillin
* Some are pathogenic to
humans

Question 7

Prokaryotes with capsules

Answer 7

Mostly polysaccharides
Protect bacteria from attack by wbc in infected animals
Stops bacterium drying out
Not necessary for survival

Question 8

What process to CYanobacterias carry out

Answer 8

Photosynthesis

Question 9

Features prokaryotic cells have

Answer 9

Flagellum
Pili - string structure to help bacteria exchange genetic material to animal cells, protection or food
Inclusions - starch, lipid reservers
Endospores - resistant to environmental stresses

Question 10

Three types of prokaryotic cells

Answer 10

Spherical - Cocci bacteria”)
Rod shaped (“Bacillus”)
Spiral shaped (“Spirillia”)

Question 11

Eukaryotic cells characteristics

Answer 11

Membrane bound nucleus
Membrane bound organelles and cytoskeleton

Question 12

Nucleus

Answer 12

Replication of dna
Decoding dna for protein production
Contains dna

Question 13

Rough endoplasmic reticulum

Answer 13

Ribosomes temporarily attached
Moves newly made proteins away from cytoplasm
Transports them to other areas of cell
Proteins chemically modified to alter function and destination

Question 14

Smooth endoplasmic reticulum

Answer 14

No ribosomes
Chemical modification of small molecules taken into cell drugs
Hydrolysis of glycogen
Synthesis of lipids and steroids

Question 15

Ribosomes

Answer 15

Float freely
Found in Cytoplasm - free or attached endoplasmic reticulum, inside mitoch and chloroplasts
Protein synthesis site

Question 16

Golgi apparatusq

Answer 16

Flattened membranous sacs - Cisternae
Received proteins from rer
Modifies, packages and sorts proteins
Site of polysaccharide synthesis for plant cell walls

Question 17

Lysosomes

Answer 17

Vesicles containing digestive enzymes from golgi
Sites for breakdown of food and foreign material brought by phagocytosis
Autophagy - digest cellular components

Question 18

Mitochondria

Answer 18

Independent genome
Energy stored in bonds of carbs and fatty acids converted to ATP by ATP synthase

Question 19

Plastids

Answer 19

Found in plants and protists
E.g. chloroplast

Question 20

Vacuoles

Answer 20

Storage, structure, reproduction, digestion

Question 21

Similarities of euk and pro

Answer 21

They both have DNA as
their genetic material.
• They are both membrane
bound.
• They both have ribosomes
• They have similar basic
metabolism
• Both occur in amazingly
diverse form

Question 22

Major differences between pro and euk

Answer 22

Eukaryotes have a nucleus
and membrane-bound
organelles, while prokaryotes
do not.
• The DNA of prokaryotes
floats freely around the cell;
the DNA of eukaryotes is held
within its nucleus.
• The organelles of eukaryotes
allow them to exhibit much
higher levels of intracellular
division of labor than is
possible in prokaryotic cells

Question 23

differences between
prokaryotes and eukaryotes

Answer 23

Eukaryotes have a nucleus
and membrane-bound
organelles, while prokaryotes
do not.
• The DNA of prokaryotes
floats freely around the cell;
the DNA of eukaryotes is held
within its nucleus.
• The organelles of eukaryotes
allow them to exhibit much
higher levels of intracellular
division of labor than is
possible in prokaryotic cells

Question 24

Fluid mosaic model structures

Answer 24

-Perform vital physiological roles
-Form boundaries between cells and their environments
-Regulate movement of molecules in/ out cell
• Lipid provides a barrier for water-soluble molecules.
• Membrane proteins are in lipid bilayer.
• Carbs attach to lipid/ protein on membrane

Question 25

What does a phosphlipid bilayer separate

Answer 25

2 awurous regions Hydrophilic - phosphate group Hyrophobic - fatty acids

Question 26

Integral membrane proteins

Answer 26

Hydrophobic regions of amino acids Penetrate across phospholipid bilayer

Question 27

Transmembrane prpteins

Answer 27

Specific orientaton Show different faces on two sides of membrane

Question 28

Peripheral membrane proteins

Answer 28

Lack hydrophobic regions and are not embedded in bilayer

Question 29

How do some proteins in the membrane remain stationary

Answer 29

Anchored to components of cytoskeleton or are trapped within regions of lipid rafts Causes unequal distribution of proteins, allowing for specialization of certain regions of cell membrane

Question 30

Glycolipid and glycoproteins

Answer 30

Glycolipid - carb bound lipid Glycoprotein - carb in membrane bonded to proteins Plasma membrane enables cells to be recognized by other cells and proteins

Question 31

Homotypic binding vs hetertypic binding

Answer 31

Homo = 2 identical molecules bind to eachother Hetero = two different

Question 32

Types of cells junctions

Answer 32

Form between cells in a tissue 1) tight junctions 2) desmosomes 3) gap junctions

Question 33

Tight junctions

Answer 33

Plasma membrane Link epithelial cells 1) restrict migration of membrane proteins adn phospholipis from one region of cell to another 2) Prevent substances moving through intercellular space

Question 34

Desmosomes

Answer 34

Hold adjacent cells together Dense plaques attached to cytoplasmic fibers + membrane cell adhesion proteins Adhesion proteins bind to the proteins of an adjacent cell

Question 35

Gap junctions

Answer 35

Monitor communication between cells. Made of specialized protein channels called connexons. Connexons span plasma membranes of two adjacent cells and protrude from them Connexons are made of proteins (connexins), which make a pore.

Question 36

Passive processes of membrane transport

Answer 36

Membranes selectively permeable - allow substances to pass and others not Simple diffusion through phospholipid bilayer Facilitated diffusion

Question 37

Diffusion def

Answer 37

the process of random movement toward the state of equilibrium

Question 38

Factors affecting diffusion

Answer 38

Distance temp size of molecule electrical charge of molecule conc gradient More lipid soluble = faster Polar and charged = slower

Question 39

Osmosis def

Answer 39

Diffusion of water across membranes Completely passive Water diffuse high -> low

Question 40

Hypertonic vs hypotonic §

Answer 40

Hyper = water leaves cell Hypo = enters

Question 41

What does facilitated diffusion depend on

Answer 41

Channel proteins and carrier proteins

Question 42

Describe the type of proteins channel and carrier

Answer 42

Protein: K+ channel = ion channel Voltage gated Carrier: Shape fits into protein, triggers other side to open letting it in

Question 43

Active transport def

Answer 43

Energy required Ions or molecules move against conc gradient ATP energy currency used directly or indirectly

Question 44

Three types of proteins for active trnsport

Answer 44

Uniport = one molecule Symport = two transported ions enter same side of protein Antiport = one leaves cell as other enters cell Symport and antiport = coupled transport

Question 45

Primary vs secondary active transport

Answer 45

Primary = sodium potassium pump - only cations ussed (K+, Na+) Secondary = use gradients e.g. ATP used for ion gradient. Gradients move substance for symport and antiport

Question 46

Example f symport system in intestinal cells

Answer 46

Glucose moves up conc gradient while mvinig sodium ions down ion conc gradient

Question 47

Endcytosis example processes

Answer 47

Phagocytosis - largest vesicles, entire cells engulfed Pinocytosis - vesicles formation, dissolved substances brought inside cell Receptor mediated endcytosis - on outside of cell in coated pits

Question 48

What is exocytosis

Answer 48

Process where materials packaged in vesicles ae secreted from the cell Vesicle membranes fuse with plasma membrane and release vesicle contents into environment

Question 49

Membranes functions

Answer 49

-Information processing -Energy transformation: -Inner mito membr = convert energy of fuel molecules -> ATP -thylakoid membrane of chloroplasts = light energy in photosynthesis -Organizing chemical reactions (efficiency)

Question 50

Pinocytosis

Answer 50

vesicle formation dissolved cells are brought into the cell layer of cells separating blood capillaries from tissue uses pinocytotic vesicles to get fluids from the blood

Question 51

Receptor-mediated endocytosis

Answer 51

similar to pinocytosis but highly specific receptor proteins exposed on outside of cell in coated pits Clathrin molecules form the “coat” of pits

Question 52

|Exocytosis def

Answer 52

process by which materials packaged in vesicles are secreted from the cell.

Question 53

Exocytosis process

Answer 53

The vesicle membranes fuse with the plasma membrane and release vesicle contents (wastes, enzymes, hormones, etc.) into the environment.

Question 54

Membranes functions

Answer 54

-Information processing -Energy transformation = mitochondrial membrane convert energy of fuel molecules to the energy in ATP. thylakoid membranes of chloroplasts are involved in the conversion of light energy in photosynthesis.

Question 55

How are membranes dynamic

Answer 55

actively participate in numerous cellular processes. Membranes continually form, move, and fuse. membrane move and change their structures, and fuse with other membranes. membranes carry out specific functions. * Despite the similar appearance and interconvertibility of membranes, they show major chemical differences depending on their location in the cell and the functions they serve. * Dynamic in both structure and activity, membranes are central to life.