Chapter 4: Cells Flashcards Preview

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Flashcards in Chapter 4: Cells Deck (76):
1

Plasma membrane

Lipid bilayer with embedded protein molecules

2

Genes

Segments of DNA that code for specific proteins

3

Enzymes

Molecules that speed up the rates of a reaction

4

Cytoplasm

All parts of the cell between plasma membrane and central region

5

Organelles

Small organised structures important for cell function

6

Cytosol

Aqueous solution containing ions and organic molecules

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Cytoskeleton

Protein-based framework. Maintains cell shape and plays key roles in cell division and chromosome segregation

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Prokaryotes

Bacteria and Archaea

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Nucleoid (P)

Central region of prokaryot. No boundary membrane.

10

Eukaryote

Domain Eukarya

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Nucleus

Central region of eukaryot. Separated a membrane

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Shapes of Prokaryotes

- Rodlike
- Spherical
- Spiral

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Prokaryotic Chromosome

Single, circular molecule of DNA

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Ribosomes

Particles in cytoplasm that use info from mRNA to assemble amino acids into proteins
rRNA groups in nucleus, then exits to form Ribosomes in cytoplasm
Either free or on membranes

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Cell wall (P)

Rigid external layer outside of plasma membrane of prokaryots. Helps protect against damage

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Glycocalyx (P)

Polysaccharide coating of cell wall. Either slime layer or capsule

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Functions of plasma membrane (pro)

- Transport
- Matabolizers

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Flagella (P)

Threadlike protein fiber that facilitates movement

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Eukarya breakdown

- Protists
- Fungi
- Animals
- Plants

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Cytosol function

- energy metabolism
- molecular synthesis
- support
- mobility

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Cell Fractionation

Method of separating parts of a cell

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Plasma membrane protiens

- Form channels for transport
- Receptors
- Trigger molecules

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Nuclear envelope (E)

Tow lipid bilayer membranes separating nucleus from cytoplasm

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Lamins (E)

Protein filaments reinforce inner surface of nuclear envalope

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Nucleoporins (E)

The proteins that used to form the nuclear pore complexes

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Nuclear Pore Complex (E)

Exchanges components between the nucleus and cytoplasm

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Nuclear Pore (E)

Channel through nuclear pore complex. Exchange of RNA

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Nuclear localization signal (E)

Short amino acid sequence distinguishing nuclear proteins

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Nucleoplasm (E)

The semiliquid substance in the nucleus

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Chromatin (E)

In nucleus
A complex of DNA and proteins

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Eukaryotic Chromosome

Each individual DNA molecule and its proteins

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Chromatin

Any collection of eukaryotic DNA molecules

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Nucleoli (E)

Plural of nucleolus
irregular structures that form around genes coding for rRNA

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Endomembrane System (E)

interrelated membranous sacs that divide the cell into functional/structural compartments.
Lipid bilayers

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Functions of endomembrane system (E)

- synthesis and modification of proteins
- transport of proteins to organells/out
- synthesis of lipids
- detoxification of some toxins

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Vesicles (E)

Small membrane-bound compartments that transfer substances between parts of the system

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Components of endomembrane system (E)

- Golgi complex
- Nuclear envelope
- Endoplasmic reticulum
- Lysosomes
- Vesicles
- Plasma membrane

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Endoplasmic reticulum (E)

extensive interconnected network of membranous channels and vesicles called cisternae

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ER lumen (E)

The space inside cisternae

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Cisternae (E)

A single membrane that surrounds the ER lumen

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Rough ER (E)

Synthesis, processing and trafficking of large variety of proteins
Membrane covered in ribosomes

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Smooth ER (E)

Synthesis lipid for membranes
Convert toxins into more tolerable substances

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Cisternae (E)

Stacks of flattened, membranous sacs that make up Golgi complex

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Secondary vesicles (E)

The vesicles that transport proteins from the Golgi complex to the plasma membrane

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Exocytosis (E)

A secondary vesicle fuses with the plasma membrane and the contents released to outside

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Endocytosis (E)

Plasma membrane forms a pocked that pinches off as a endocytic vesicle

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Lysosomes (E)

Small vesicles that contain enzymes for the hydrolysis (digestion) of complex molecules
Found in animals and protists

48

Autophagy (E)

The process when an endocytic vesicle fuses with a lysosome to digest organelles not functioning correctly

49

Phagocytosis (E)

Process when some types of cells engulf bacteria or other debris and break them down

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Cellular respiration

Energy-rich molecules are broken down to H2O and CO2 by mitochondrial reactions, with the release of energy

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Chloroplasts

Site of photosynthesis in plant cells and algae

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Mitochondrial membranes

Outer: Smooth. Covers outside of organelle
Inner: Expanded by folds called cistae

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Mitochondrial matrix

Innermost compartment of the mitochondrion.

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Endosymbiotic theory

Mitochondria may have originated from mutually advantageous relationship between ingested prokaryot and the cell that ingested it

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Microbodies (E)

Small, simple membrane-bound organelles found in various forms in virtually all eukaryotic cells

56

Structural elements of cytoskeleton

- Microtubules
- Intermediate filaments
- Microfilaments

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Centrosome

A site near the nucleus where cytoskeletal microtubules radiate out from

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Centrioles

Midpoint of microtubles

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Functions of microtubles

- Anchor membranous organelles
- Tracks for vesicle movement
- Separate and moving chromosomes during division
- Maintaining shape

60

Function of intermediate filaments

Structural support in many tissues and cells

61

Motor proteins

- Kinesins
- Dynesins
- Myosins

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Cytoplasmic Streaming

Transporting nutrients, proteins and organelles.
Responsible for amoeboid movement

63

Chloroplasts

Highly specialised vacuole
Site of photosynthesis
Two boundary membranes

64

Amyloplasts

Colourless plastids that store starch
(starch product of photosynthesis)

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Chromoplasts

Responsible for colours of ripening fruit/autumn leaves

66

Thylakoids

Flattened closed sacs that make up the third membrane system within a chloroplast. Stacked to form grana

67

Chlorophyll

The primary light absorbing molecule.

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Central vacuoles

Large vesicles in plant cells
Store salts, organic acids, sugars, storage proteins, pigments, waste

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Tonoplast

Membrane surrounding central vacuole

70

Cell wall (E)

Provide support
Contain pressure caused by vacuole
Protect against bacteria and fungi

71

Middle lamella

Polysaccharide (pectin) layer between plant cells.

72

Plasmodesmata

Channels that perforate primary and secondary cell walls

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Levels of molecules that hold cells together

- Cell adhesion molecules: Bind cells together
- Cell junctions: Seal space between cells, provide direct communication
- Extracellular matrix (ECM): Protects cell, provides mechanical linkages

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Cell adhesion molecules

Glycoproteins embedded in plasma membrane
Maintain body form and structure
Play part in tissue recognition

75

Types of cell junctions

- Anchoring junction
- Tight junction
- Gap junction

76

Extracellular Matrix componants

- Collagen
- Proteoglycans
- Fibronetins