36 terms

Animal Biology Unit 4

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Origin of Life Stages
Stage 1: Synthesis of Organic Molecules

Stage 2: A- Synthesis of protocells
B- Synthesis of organic macromolecules

Stage 3- Abiogenesis
Protocells
.A self organized spherical collection of lipids
.Likely formed the first membranes
RNA World Hypothesis
proposes that RNA led to life on Earth b/c it is the only macromolecule known to self-replicate
Abiogenesis
the process of life arising from non-living matter
Cell Theory
- Basic unit of life
- All living organisms are composed of one or more cells
- All cells arise from pre-existing cells
Last Universal Common Ancestor (LUCA)
The most recent common ancestor of all life on Earth
3 Domains of life
1. Archaea
2. Bacteria
3. Eukaryotes
Prokaryotic Cells
Cells lacking a nucleus and other organelles
Plasma Membrane
a phospholipid bilayer that forms the boundary between the cell and its environment
Cell Wall
rigid structure that provides protection to prokaryotic cells and prevents water loss
Capsule
Outermost layer of prokaryotes, comprised of sugars
Ribosomes
An ancient molecular machine that functions as a factory for building proteins
Cytosol/ Cytoplasm
Thick, jelly-like fluid on the inside of a cell which everything else is suspended in
Chromosomes
information-carrying structure of all living cells
Nucleoid
area of prokaryotic cell where chromosome is localized
Plasmid
Small, circular extrachromosomal piece of DNA
Flagella
ash-like appendage that protrudes from the cell body of some, but not all, prokaryotic cells
Eukaryotes
Any organism whose cells contain a nucleus and other membrane-bound organelles
Organelle
a membrane-enclosed compartment with a specialized function within a eukaryotic cell
Nucleus
The genetic control center of a eukaryotic cell
Nuclear Envelope
phospholipid membrane that defines the nuclear compartment
Nuclear Pores
protein channels in the nuclear envelope
Nucleolus
Dense spot within the nucleus where ribosomes are assembled
Endoplasmic Reticulum
Extensive membranous network, acts as the main site for protein and lipid synthesis within the cell
Rough ER
has ribosomes attached to it, site of protein synthesis
Smooth ER
site of lipid synthesis, does not contain ribosomes
Transport Vesicles
sacs of membrane that bud off from the cell's organelles
Golgi Apparatus
receives, refines, stores, and distributes the chemical products of the cell
Lysosomes
an organelle filled with digestive enzymes for breaking down macromolecules
Cytoskeleton
A series of intercellular proteins that help a cell with shape, support, and movement
Cilia and Flagella
hair-like projections that function either to move a cell or to move things across a cell
Mitochondria
organelle where energy is generated by the breakdown of chemical compounds
Chloroplasts
organelle, found only in plant and algal cells, converts sunlight to chemical energy (anabolism)
Symbiosis
a close, long-term physical interaction between organisms of different species
Endosymbiosis
occurs when an organism of one species lives inside an organism of another species
Endosymbiotic Theory
states that the energy organelles of eukaryotes originated as a symbiosis between separate single-celled organisms