Unit 2 Flashcards
What is Galileo Galilei known for?
Invented microscope
Robert Hooke
created term “cellular” which is now called a cell, while observing a cork under a microscope
Antony Van Leewenhoek
observed animalcules in tarter scrapings from his teeth
Robert Brown
botanist, observed and named nucleus
Matthias Schleiden
botanist, stated all plants are made of cells
Theodor Schwann
zoologist, stated all animals are made of cells
Rudolf Virchow
physiologist, said cells arise from pre-existing cells
Cell theory (3 facts)
- all organisms are composed of one or more cells
- the cell is the most basic structure and function in living organisms
- cells arise only from other cells
Cell size?
Cells must be small, as a cell grows, its volume increases faster than surface area which leads to the surface area not providing enough nutrients, or letting water and oxygen in or out. Folds and indentations help further increase surface area
Types of Microscopes? (3)
Compound light microscope
Transmission electron microscope (TEM)
Scanning electron microscope (SEM)
Compound light microscope
light rays passing through specimen are brought into focus by a set of glass lenses and observed by eye
TEM microscope
electrons passing through a specimen are brought into focus by a set of magnetic lenses and image is projected onto a fluorescent screen
SEM microscope
beam of electrons is scanned over the surface of a specimen
3 dimensional image is projected on a TV screen
Types of cells? (2)
Prokaryotic cells- DNA not contained in nuclear membrane (not membrane-bound) EX. bacteria
Eukaryotic cells- DNA contained in a nuclear membrane (membrane -bound with mitochondrias and chloroplasts) EX. human body cellls
Cell components?
Nucleus:
Nuclear envelope(membrane):
Nucleolus: dense mass of proteins and RNA inside nucleus
Chromosome:
Endoplasmic reticulum (ER):
Ribosomes:
Cytoskeleton:
Cell Wall:
Chromoplasts-
Amyloplasts-
Central vacuole-
Cell (plasma) membrane-
Chloroplasts-
Mitochondria-
Centrioles:
centrosome (microtrubule organizing center):
Nucleus: contains chromatin (all of a cell’s dna) and nucleoplasm
Nuclear envelope(membrane): is a phospholipid bilayer that controls what enters/exists nucleus
Nucleolus: dense mass of proteins and RNA inside nucleus, RNA subunits are assembled here
Chromosomes: individual DNA molecules and histones (proteins that it wraps itself around)
Endoplasmic reticulum (ER): can be rough or smooth, system of membranous channels continuous with nuclear membrane
Ribosomes: site of protein synthesis, abundant in cells that secrete hormones and enzymes
cytoskeleton: Cyto= cell, a network of interconnected filaments and tubules that extends from the nuclear membrane to the plasma membrane in Eukaryotic cells
Cell wall- surrounds plasma membrane in plants, fungi, and some protists and bacteria–not animals
Provides support and protection for the cell
- Primary cell wall- pliable, composed of cellulose
- Secondary cell wall- deposited inside primary cell wall
Rigid. Maintains cell shape
Chromoplasts- contain carotenoids (red and orange pigments)
Give plant tissues their color
Amyloplasts- store starch grains
No pigments, colorless
Central vacuole- provides turgor pressure (internal pressure) in plant cells, stores amino acids, sugars, wastes, and water
Cell (plasma) membrane- phospholipid bilayer that controls what enters and exits the cell
Chloroplasts-
site of photosynthesis,
solar energy is converted to chemical energy in carbohydrates
Contain chlorophyll
Mitochondria- site of aerobic respiration
Where atp is made
Organic compounds are broken apart and atp molecules are formed
Double-membrane structure
Folds of inner membrane (cristae) provide greater surface area for chemical reactions
Cells that require more energy have more mitochondria
Have dna and can divide on their own
Centrioles: short cylinders of microtubule triplets with a 9+0 arrangement
centrosome(microtrubule organizing center)- Two centrioles arranged at right angel to each other form
