CELS191 Module 1 Flashcards

to learn module 1 (110 cards)

1
Q

1µm

A

1/1000 mm

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2
Q

1mm

A

1000µm

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3
Q

1µm

A

1000nm

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4
Q

Eukaryote cells range

A

10-100 µm

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5
Q

Prokaryote cells range

A

less than 5 µm

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6
Q

mitochondria size

A

1-10 µm

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7
Q

chloroplasts size

A

2-5µm

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8
Q

Evolution

A

When you have organisms that vary, pass on their
characteristics and survive differentially

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9
Q

Natural selection

A

the reproductive success of the members of a population best adapted to the environment

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10
Q

Phylogenetic Trees

A

identifying shared characters makes family trees of organisms.

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11
Q

Origin of life, 3 domains

A

Bacteria, Eukarya, Archaea

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12
Q

Endosymbiosis theory

A

Mitochondria are derived from proteobacteria, and chloroplasts from cyanobacteria.

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13
Q

Prokaryotic VS Eukaryotic Cells

A

membrane-enclosed organelles are present in eukaryotes
Prokaryotic no nucleus

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14
Q

Amino acids, Nucleobases, Simple carbohydrates, Fatty acids

A

Building blocks

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15
Q

Macromolecules

A

Proteins ,DNA, RNA, Complex carbohydrates, Lipids

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16
Q

Super molecular assemblies

A

Membranes, Ribosomes, Chromatin

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17
Q

Organelles

A

Nucleus, Mitochondria, Golgi, ER

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18
Q

4 Levels of carbohydrates

A
  1. Monosaccharides (single unit)
  2. Disaccharides (two joined)
  3. Oligosaccharides (3-10 complex)
  4. Polysaccharides (more than 10)
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19
Q

Functions of Carbohydrates

A

Recognition, Energy, Structure

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20
Q

Nucleic acids

A

polymers of nucleotides

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21
Q

Proteins

A

polymers of amino acids
the 20 amino acids differ by their ‘R’ group

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22
Q

Lipids

A

Not polymers
Heterogeneous - fats and steroids
Hydrophobic

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23
Q

Functions of Lipids

A

Structural, Regulatory, Energy

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24
Q

What must a cell do?

A

Manufacture cellular materials
Obtain raw materials
Remove waste
Generate the required energy
Control all of the above

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25
Plasma membrane
At the boundary of each cell, Provides special conditions within the cell and acts as a semi-permeable barrier
26
Plasma membrane is made of
double layer of phospholipids with various embedded or attached proteins
27
Membrane Proteins are involved in
Signal Transduction, Cell Recognition, Intercellular Joining, Linking Cytoskeleton & Extracellular Matrix, Membrane Transport
28
Passive Transport (no energy)
Diffusion, They move down their concentration gradient and thus do not require energy
29
Facilitated diffusion
No energy is required but some channels open or close in response to signals Carriers undergo a shape change to help guide the molecule
30
osmosis
The movement of water across a cell membrane requires channels called aquaporins. High-concentration to low concentration
31
Active Transport (needs energy)
Move specific substances against their concentration gradient Active transport allows a cell to have an internal concentration of a substance that is different from its surroundings
32
Co-transport
indirect active transport one substance is pumped across the membrane and its concentration gradient is used to power the movement of a second substance against its concentration gradient
33
Organelles
Provide special conditions for specific processes. Keep incompatible processes apart
34
Only animal cells have
Lysosomes
35
Only plant cells have
Chloroplasts & Central vacuole
36
The Endomembrane System
a membrane system interconnected by direct physical contact or transfer by vesicles
37
Smooth Endoplasmic Reticulum (sER)
Metabolism of carbohydrates Lipid synthesis for membranes The amount of sER can be increased or decreased to meet demand
38
Rough Endoplasmic Reticulum (rER)
Rough appearance due to ribosomes Involved in protein synthesis Secreted and membrane-bound proteins enter the lumen (interior) of the rER and are processed by the rER and the rest of the endomembrane system for release from the cell or retention on the cell membrane
39
Function of the Golgi complex
- Vesicles from endoplasmic reticulum arrives at the cis face and processed vesicles leave at the trans face - Sorting proteins, Adds molecular markers to direct proteins to the correct vesicles before ”budding” from the trans face - Directing vesicle trafficking, Adding molecular “tags” to vesicles leaving the trans face to direct them to the correct targets
40
Glycosylation
Addition (or modification) of carbohydrates to proteins Important for secreted or cell surface proteins
41
Types of vesicles
Transport vesicles Secretory vesicles Vacuoles
42
Exocytosis
Transports material (glycoproteins) out of the cell or delivers it to the cell surface
43
Endocytosis
the cell takes in molecules and particulate matter at the plasma membrane
44
Phagocytosis
uptake of “food” particles pha = ATE
45
Pinocytosis
up-take of extracellular fluid containing various solutes such as protein and sugars Pino = drink
46
Receptor-mediated endocytosis
allows the cell to take up bulk quantities of specific substances which may be present only low concentrations in the extracellular fluid
47
Lysosomes
membrane-bound organelles made by the rER and Golgi body containing hydrolytic enzymes Lysosomes digest and recycle unwanted cellular materials
48
Vacuoles
Large vesicles derived from the rER and Golgi can perform lysosome-like functions large central vacuole absorbs water allowing plant cells to grow without a large increase in cytoplasm
49
Adenosine Triphosphate (ATP)
ATP is an energy carrier
50
The cell needs energy for
for mechanical work to make new materials for transport to maintain order
51
The Site of Cellular Respiration
Mitochondria
52
The Mitochondrion: Structure
Has two membranes: inner & outer mitochondrial membranes - Inner membrane highly folded (cristae) functionally important - Intermembrane space functionally important - Mitochondrial matrix inside the inner membrane
53
CR: Cellular Respiration: Stage 1 - Glycolysis
In the cytosol Sugar – glucose is converted into two pyruvate molecules Generates: 2ATP – energy carrier AND electrons are transferred to the high energy electron carrier - NAD+ making NADH
54
CR: Stage 2 – Pyruvate Oxidation & Citric Acid Cycle
In the Mitochondrial Matrix: pyruvate molecules are converted to 2 Acetyl CoA molecules. 2 Acetyl CoA molecules enter the citric acid cycle. Output is energy carrier ATP and high energy electron carriers NADH & FADH2.
55
CR: Stage 3 – Oxidative Phosphorylation
Inner Membrane of the Mitochondrion Part 1: The Electron Transport Chain electrons move through protein complexes embedded in the inner membrane. As the electrons move, protons (H+) are pumped across the membrane Part 1: A Proton Gradient is Generated Protons (H+) accumulate in the intermembrane space Part 2: Chemiosmosis The proton gradient across the inner membrane powers ATP synthesis Part 2: Chemiosmosis ADP + Pi ATP
56
Cellular respiration
Glucose and oxygen are consumed Carbon dioxide, water and ATP are produced
57
The Site of Photosynthesis
Chloroplasts
58
Chloroplasts: Structure
Three Membranes Outer Inner Thylakoid Three Compartments Intermembrane space Stroma Thylakoid space
59
Chloroplasts: Function
Light reactions take place on the thylakoid membrane. Carbon fixation occurs in the stroma
60
The Light Reactions
The thylakoid membrane contains chlorophyll Chlorophyll absorbs light energy The light energy absorbed by chlorophyll results in the movement of high-energy electrons
61
The Photosynthetic Electron Transport Chain
High energy electrons produced from chlorophyll move through the Photosynthetic electron transport chain Photosystem II Photosystem I
62
The Calvin Cycle
The output of the Calvin cycle is a 3 carbon sugar that, when combined with another 3 carbon sugar, is converted to glucose. The ATP and NADPH produced in the light reactions are only used in the Calvin Cycle
63
Energy Supply in Plants & Animals: Glucose
Both plants and animals breakdown glucose in cellular respiration to generate ATP Plants generate glucose during photosynthesis and then break this down during respiration
64
Energy Supply in Plants & Animals: ATP
ATP is generated in both respiration and photosynthesis This requires a proton gradient across a membrane in both the chloroplast and mitochondrion
65
Plant Cell Components
Plasmodesmata The Cell Wall + The Protoplast
66
Cell Wall Structure: Cellulose - A Major Component
Cellulose Forms Microfibrils
67
Two phases of cell wall structure
Phase 1: Microfibrils, Cellulose Phase 2: Matrix Pectin polysaccharides Hemicellulose polysaccharides
68
Hemicellulose
a heterogeneous group of polysaccharides. Long chain of one type of sugar and short side chains form a rigid structure.
69
Pectin
branched, negatively charged polysaccharides. Bind water and have gel-like properties
70
Extensin cross-linking of pectin and cellulose
dehydrates the cell wall, reduces extensibility and increases strength
71
Constitutive exocytosis
releases extracellular matrix proteins
72
Cytoskeleton
A network of microtubules, microfilaments (and intermediate filaments) that extend throughout the cytoplasm. It Helps maintain the cell shape and position of organelles within cells. the cytoskeleton rapidly disassembles and reassembles
73
Synthesis of the Primary Cell Wall
Cellulose-producing rosettes are protein complexes (enzymes) that span the plasma membrane.
74
Cell Wall Functions in Regulating Cell Shape
influences cell morphology provides structural support prevents excessive water uptake
75
Orientation of the cellulose microfibrils influences cell morphology
a) Randomly oriented. The cell will expand equally in all directions. b) Right angles to the ultimate long axis of the cell. The cell will expand longitudinally along that axis.
76
How The Cell Wall: Provides Structural Support
The protoplast pushes against the cell wall. The cells become rigid and this maintains the plant structure. Water loss from cells reduces the protoplast volume and the protoplast does not press on the cell wall
77
The Cell Wall: Prevents Excessive Water Uptake
As water enters the cell by osmosis, the protoplast expands and pushes against the cell wall. Pressure from the cell wall limits the volume of water that can be taken up. Vacuoles are important in this process because they contain water and make such a large portion of the protoplast.
78
Vacuoles: Structure
A vacuole is an organelle surrounded by a single membrane. It is highly selective, controlling much of what enters and leaves the vacuole. Water moves in the vacuoles by osmosis (passive transport)
79
Vacuoles: Function in Regulation of Cell Shape
The plant cell wall limits water uptake and prevents the cell bursting. Plant cells build up a large internal pressure that contributes to plant structural support.
80
The Secondary Cell Wall
Not all plant cells have a secondary cell wall Produced only after cell growth has stopped Thicker and stronger than primary cell walls Provides more structural support than the primary cell wall
81
Secondary Cell Wall: Structure
Made up of multiple layers. Microfibrils in each layer have different orientations. This strengthens the secondary wall
82
Lignin
The second most abundant organic macromolecule Lignin is a complex polymer Confers strength and rigidity to the secondary cell wall and acts to exclude water
83
Plasmodesmata: Cell Communication
Plasmodesmata are intercellular connections, that enable cell-to-cell communication.
84
Microtubules
Microtubules are composed of tubulin subunits. They may radiate out from an organising centre (centrosome). Microtubules resist compression,Thus help maintain cell shape
85
Microtubules can also provide cell motility
Flagella: “snake-like” motion Cilia: “rowing-like” motion If cells are fixed in place beating of cilia moves fluid past them
86
Microtubules are also involved in organelle motility within the cell
ATP-powered motor proteins can “walk” organelles along microtubules. Allows vesicles, or other organelles, to be transported to specific targets within the cell
87
Microfilaments
Microfilaments are a double chain of actin subunits Microfilaments resist tension The cortical network under the plasma membrane helps make this region less fluid and thus maintains cell shape
88
Intermediate Filaments
Are made of various proteins including: keratins in hair. lamins in the nucleus. neurofilaments in neurons. Supercoiled into “cables” Less dynamic than microtubules or microfilaments Intermediate Filaments form relatively permanent cellular structures
89
Three major types of Cell Junctions
Tight Junctions Desmosomes Gap Junctions
90
Tight Junctions
Hold neighbouring cells tightly pressed together May form a continuous seal Prevents movement of fluid across cell layers
91
Desmosomes
Anchoring junction Provide attachments between sheets of cells e.g. muscle Act like rivets (a “torn muscle” is a torn desmosome) Connected into the cell by intermediate filaments
92
Gap Junctions
A point of cytoplasmic contact between two cells Ions and small molecules can pass from cell to cell Allows rapid cell to cell (intercellular) communication
93
How Are Cells Joined Together?
The Extracellular Matrix
94
Extracellular Matrix (ECM)
The ECM is composed of material secreted by cells This secretion occurs by constitutive exocytosis Most ECM proteins are glycoproteins The most abundant ECM glycoprotein is collagen
95
proteoglycan complex matrix
Proteoglycans are proteins with extensive sugar additions. Proteoglycans trap water within the ECM. Water resists compression and thus helps retain tissue shape
96
Ribosomes: Structure
Complexes made of ribosomal RNAs & proteins Found in two locations: bound ribosomes attached to rough ER free ribosomes in the cytoplasm
97
Ribosomes: Function
Carry out translation The more protein synthesis a cell needs to do, the more ribosomes it has
98
The Nucleus
The most prominent organelle (5-10 µm diameter) One nucleus per cell (in most cases) Contains most of the cell’s genes
99
The Nucleus: Structure
Surrounded by the nuclear envelope Has channels called nuclear pores Contains tightly packaged DNA Has a prominent area called the nucleolus
100
The Nucleus Envelope
Composed of two membranes outer and inner membranes with perinuclear space in between Each membrane is a phospholipid bilayer Outer membrane continuous with ER
101
Nuclear Lamina
The inner surface of nuclear envelope is lined by the nuclear lamina, Which is composed of intermediate filaments Maintain the shape of the the nucleus Helps organise the packing of the DNA within the nucleus
102
Nuclear Pores
Channels made of proteins (nucleoporins) that form the Nuclear Pore Complex Spans nuclear envelope 1000 per cell Controls the movement of molecules out of, or into, the nucleus (nucleo-cytoplasmic exchange)
103
Nucleus to Cytoplasm
mRNA, tRNA and ribosomal subunits move from nucleus to cytoplasm
104
Cytoplasm to Nucleus
Control signals, building materials and energy move from cytoplasm to nucleus
105
The Nucleolus
A prominent nuclear structure within non-dividing cells Non-membrane bound specialised region within the nucleus. Responsible for making ribosomal RNA & ribosomal subunits
106
The DNA helix interacts with specific proteins called
histones
107
karyotype
Chromosomes can be displayed as a karyotype which can be used to screen for chromosomal defects
108
Euchromatin
less dense, contains genes being used by that cell Allows access
109
Heterochromatin
more dense, contains genes not being used by that cell
110