Lecture 1 Flashcards
What is biology?
-It is the study of life
-two forms are constancy of mechanisms and variety (forms)
What is cell biology
Cell biology is the study of cells which are the fundamental units of life.
-key to every biological problem is in cells,
-cell biology is heart of modern research
-cell function is insight to human health and disease
Contributors to the discovery of cells
Hook- First discovered cells and named them
-Leeuwenhoek made better lenses to look at cells better and discovered the nucleus
-Schleiden was the first to discover plants also had cells
-Schwann concluded all living things have cells
-Virchow discovered cells came from other cells
Cell theory
THREE STEPS FOR CELL THEORY
1) All organisms have one or more cells
2) Cells are the basic unit of structure of an organism
3) Cells come from preexisting cells
Cells
-Just by appearance, there is a huge diversity of cells
-there are over 200 differentiated cell types in mammals
Universal features of all cells on Earth?
1) Hereditary info stored in DNA
-sequential arrangment of ATCG determines biology
-genome sequencing
-complete genomes of 10,000s species are known like human, bacteria and yeast
2) All cells replicate their DNA by templated polymerization
3) All cells follow central dogma
4) All cells use proteins as catalysts (help maintain structures, movements, signal sensing and proteins put genetic info into action)
5) All cells are bounded by plasma membrane, Nutrients and waste material have to pass through it (selective barrier=acquire nutrients and retain cellular contents), without this membrane, cell cannot function its chemical system
5)All cells utilize conserved metabolic pathways to convert food or sunlight into energy/ ATP(thermal movement vs fixed order)
Summary of universal features
1) The cell is a minimal self-reproducing unit
2) All cells store genetic information in DNA
3) All cells template polymerization to duplicate DNA
4) Cells follow central dogma
5) Cells use proteins as catalysts
6) All cells bound by plasma membrane
7) All cells require ATP for energy
Global Tree of Life
Prokaryotes have no nucleus= bacteria and archaea
-Bacteria are the most diverse group of organisms
Eukaryotes
-Eukaryotic cells contain network of cytoskeletal filaments transversing in cytoplasm
-Cytoskeleton has three protein polymer systems
1)microfilaments
2)microtubules
3)intermediate filaments
(these polymer systems define mechanical properties of cells and serve as tracks for cellular cargo)
Eukaryotic cells
-Contain many membrane enclosed organelles
-Have evolved by symbiosis (chloroplasts evolved from photosynthetic bacterium engulfed by eukaryotic cell) (eukaryotic have hybrid genomes)
-Eukaryotic lineages are single celled organisms
-multicellular organisms like plants and animals are on seperate clades which suggests evolution serparetly more than once
Cell and Tissues
Cell in the tissues of multi cell organisms must interact in defined way to communicate their activities
-extra cellular matrix found outside of cells is critical for allowing cells to form tissues with defined form and function
