Biology Chapter 3 (part 1) Flashcards
1
Q
Cells are small becasue…
A
nutrients need to diffuse across the cell
2
Q
the largest a cell can be is…
A
~100 micrometers in diameter
3
Q
some cells have special modifications that…
A
increase surface area relative to their cell volume
4
Q
neurons are
A
very long and thin
5
Q
cells lining the digestive tract have
A
microvilli (finger-like projections that increase surface area)
6
Q
in order for organisms to become larger, they must become…
A
multicellular
7
Q
all living organisms are composed of…
A
cells
8
Q
the cell is a basic unit of…
A
all living organisms
9
Q
cells are the ___________ that can survive independently
A
smallest single unit
10
Q
all cells come from…
A
pre-existing cells
11
Q
all cells contain ___________ which is passed through to new cells through __________
A
genetic material (DNA), cell division
12
Q
all cells are either…
A
prokaryotic or eukaryotic
13
Q
Plasma Membrane
A
forms the boundary of the cell, controls the permeability of the cell to water, and dissolves substances
14
Q
cytoplasm fills the…
A
interior of the cell
15
Q
the plasma membrane is a sheet of…
A
lipids with embedded proteins
16
Q
the molecules comprising the lipid layers are called…
A
phospholipids
17
Q
structure of phospholipids
A
polar head (hydrophilic), non-polar tails (hydrophobic)
18
Q
polar regions consist of…
A
phosphate group
19
Q
non-polar regions consist of…
A
fatty acids
20
Q
receptor proteins
A
binds substances outside the cell that affect the function of that cell
21
Q
antigens
A
they act as markers, such as blood type proteins
22
Q
transport proteins
A
allow substances to cross the membrane
23
Q
Prokaryotic
A
- Lack a nucleus and do not have an extensive system of internal membranes.
- All eubacteria and archaea are prokaryotic
24
Q
Eukaryotic
A
- Have a nucleus and have internal membrane-bound compartments.
- All organisms other than bacteria are eukaryotic.
25
Prokaryotes are the _________ cellular organisms
Simplest
26
prokaryotes have no or few...
interior compartments
27
prokaryotes cell wall
combination of disaccharides and amino acids known as peptidoglycans confer a rigid structure
28
Capsule
may surround the cell wall
29
cytoplasm
uniform with little or no internal
support framework
30
ribosomes
scattered throughout the cytoplasm
31
Nucleoid region
area of the cell where DNA is localized.
→ It is not membrane-bound, so not a true nucleus
32
flagellum
a collection of protein fibres that extend from the cell surface.
- aids in locomotion and feeding
33
pilus
is like a short flagellum
- Aids in attaching to substrates and in exchanging genetic information between cells
34
Eukaryotic cells are...
larger and more complex than prokaryotic cells
35
Eukaryotic cells structures
* They have a plasma membrane encasing a cytoplasm.
* Internal membranes form compartments called organelles.
* The cytoplasm is semi-fluid and contains a network of protein fibres that form a scaffold called a cytoskeleton.
36
many organelles are immediately _________ under a microscope
visible
37
nucleus
A membrane-bound compartment for DNA
38
Endomembrane system
Give rise to internal
membranes found in the cell.
Each compartment provides
specific conditions favouring
a particular process.
39
The nucleus stores...
hereditary information (DNA)
40
the nucleus controls...
all functions within a cell
41
nuclear envelope
the nuclear surface, a double-membrane
42
nuclear pores
groups of proteins form these openings. they permit proteins and RNA to pass in and out of the nucleus
43
During most of the nuclear cell cycle:
DNA is loosely coiled into strands called chromatin, which are not visible as segments.
→ Protein synthesis occurs when the DNA is in the chromatin form
44
During cell division and replication:
DNA of eukaryotes is packaged into segments and associated with stabilizing proteins (known as histones).
- These proteins enable the DNA to be wound tightly, so it appears condensed.
45
DNA/Protein complex is called
chromosome
46
the nucleus is also the site for...
subunits if the ribosome is to be synthesised
47
the nucleolus
is a dark-staining regain of the nucleus.
- contains genes that code for rRNA
48
endoplasmic reticulum (ER)
an extensive system of internal membranes. Some form channels and interconnections. other portions become isolated spaces enclosed by membranes (vesicles)
49
Rough ER
a segment of the ER dedicated to protein synthesis. the surface looks pebbly and rough spots are due to embedded ribosomes
50
Smooth ER
a segment of the ER that aids in the manufacture of carbs and lipids. the surface is smooth because it contains so ribosomes
51
Golgi bodies
are a flattened membrane that forms collective stacks called Golgi complex. function to collect, package, and distribute molecules manufactured in the cell
52
mitochondria
the powerhouse of the cell. a site for series of chemical reactions associated with oxidative metabolism. is surrounded by two membranes
53
Ribosomes
composed of rRNA and protein. not membrane-bound and are the site for protein synthesis
54
Golgi complex also gives rise to...
lysosomes
55
lysosomes
membrane-bound structures contain
enzymes that the cell uses to break down macromolecules.
* Worn-out cell parts are broken down, and their components are recycled to form new parts.
* Particles that the cell has ingested are also digested
56
Peroxisomes
different components of the
endomembrane system that are also found in the cell.
57
reactions confined to peroxisomes function to
1. Detoxify harmful by-products of metabolism, and
2. Convert fats to carbohydrates in plant seeds for growth.
58
centrioles
found in most eukaryotic cells are
involved in the organization of spindle fibres (microtubules) that
transport chromosomes during cell division.
59
The cytoskeleton consists of an internal framework of
protein fibres that...
* Anchor organelles to fixed locations,
* support the shape of the cell, and
* help organize ribosomes and the enzymes needed for synthesis activities.
60
Microfilaments
~ 7 nm diameter
→ long, slender fibers made of the protein actin
61
Intermediate filaments
~ 10 nm diameter
→ composed of a family of related proteins that share similar structural and molecular features
62
Microtubules
~ 25 nm diameter
→ hollow tubes made of the protein tubulin
63
Cellular motion is associated with the movement of...
actin microfilaments and/or microtubules
64
some cell components "crawl" by ...
coordinating the rearrangement of actin microfilaments
65
some cells "swim" by ...
coordinating the beating of microtubules grouped together in the form of flagella or cilia.
66
Microtubules provide...
structural framework that allows other molecules to ‘crawl’ along the microtubule
67
Collagen and elastin proteins form...
a protective layer over the cell surface and allows tissues to be strong yet flexible
68
Fibronectin protein connects...
the extracellular matrix (ECM) to the plasma membrane
69
Fibronectin molecules connect to...
integrins, membrane-spanning proteins that extend into the
the cytoplasm of the cell.
70
This extracellular—intracellular connection allows...
the ECM to influence cellular behaviour and to coordinate groups of cells functioning as tissues.
71
Collagen
makes tissues strong
72
Elastin
makes tissues stretch
73
Proteoglycans
contain sugars that hold water in
connective tissues and allows for lubrication and for tissue to withstand force – joints
74
Fibronectin
binds ECM components and plays a role in adhesion and is important for wound healing
75
Integrins
connect cytoskeleton to ECM and transmit information into or out of the cel
76
cell junctions
are structures that connect cells together and/or allow cells to communicate with other cells.
77
Tight junctions
hold cells together and prevent
molecules from moving through the space between cells
78
Anchoring junctions
have adhesion molecules that
anchor cells to the ECM; they are found in tissues that undergo a lot of stretching
79
Gap junctions
form direct channels between cells
that decreases time required to communicate
