Chapter 1 Flashcards
Definition of a Cell
Membrane-enclosed units filled with concentrated aqueous substance, endowed with ability to create copies of themselves
There may be up to ______ million distinct species of living things on our plant
100
Calls Vary in Appearance and Function
- A Lactobacillus in a piece of cheese is a few _________ while a frog egg has a diameter of about 1 _________
Micrometers, Millimeter
How are Cells Different?
List 3
1) Size (Lactobacillus vs. Frog Egg)
2) Shape (Nerve Cell vs. Paramecium)
3) Chemical Requirements (Some need O2, for others its deadly)
How are Cells Similar?
List 3
1) Composed of same sort of molecules
2) All contain genetic information in the form of genes that is carried in DNA molecules
3) All carry out Transcription and Translation
4) All obtain energy, grow, and divide
What is the process of a cell reproducing?
Duplicating their genetic material and other compounds, and then dividing in two -> produces a pair of daughter cells
What do proteins do for a cell?
They provide structural support, act as chemical catalysts, molecular motors etc.
How do viruses operate if they cannot replicate by themselves?
They hijack the reproductive machinery of the cells they invade to make copies of themselves
What are mutations?
What do they do to the chances of an organism’s survival?
Mutations are what changes the sequence of nucleotides in the DNA, making daughter cells not an exact replica of their parent
Good Mutation -> Better survival
Bad Mutation -> Elimination of organism
Neutral Mutation -> Tolerates
All Living Cells Have Evolved from the Same Ancestral Cell
Tell the story of this
All living cells inherited their genetic instructions from the same common ancestral cell that existed between 3.5 and 3.8 billion years ago
What is the definition of a Cell’s Genome?
The entire sequence of nucleotides in an organism’s DNA -> provides genetic program that instructs a cell how to behave
How can a Fat Cell, Skin Cell, and Bone Cell have anything in common?
They all stem from the same fertilized cell and contain the same genetic information but express different genes
DNA is identical in every cell
How do Light Microscopes work?
They use visible light to illuminate specimens
How do Electron Microscopes work?
They use beams of electrons because electrons have a shorter wavelength and this allows us to see fine details of cells
What is the Cell Theory
The theory that all living cells are formed by the growth and division of existing cells
Plasma Membrane Definition
An enclosed membrane that separates the interior of the cell from its external enivronment
Cytoplasm Definition
Transparent substance that contains everything within the cell
Ribosome Definition
Complex in which RNA is translated into proteins
Transmission Electron Microscope is used for what?
Looking at thin sections of tissue
What has the simplest structure and comes closest to showing us life stripped down to its essentials?
Bacteria
What are the different shapes of prokaryotes?
Cocci, Bacillus, or Spirilla
Characteristics of Prokaryotes
What is the literal meaning of Prokaryote?
NO NUCLEUS
Tough protective coat that surrounds the cell membrane
Single compartment of cytoplasm which holds the DNA
Reproduce Rapidly (5 Billion in 11 Hrs)
Rapid reproduction allows them to transform to be resistant to new antibiotics
Organic or inorganic food sources can be used for food
Before Nucleus
Mitochondria Definition
Produce ATP through the oxidation of food molecules
ONLY FOUND IN EUKARYOTIC CELLS
Contain their OWN DNA
Two separate membranes
Bacteria and Archaea diverged from a common prokaryotic ancestor around ______ billion years ago
3.5
Where can Archaea be found?
Hostile environments such as the hot acid of volcanic springs, airless depths of marine sediments, sludge of sewage treatment plants etc.
Examples of Eukaryotic cells that live as single-celled organisms
Amoebae and Yeasts
Eukaryotic Cells are _____ than prokaryotic cells, more complex that prokaryotic cells, posses a variety of different membrane enclosed _________
HAVE A ______
Bigger, Organelles, NUCLEUS
Without mitochondria, plants, animals, and fungi…
Couldn’t use oxygen to extract energy needed from food molecules
How did mitochondria evolve?
they are though to have evolved from aerobic bacteria that were engulfed by an anaerobic eukaryotic cell and lived inside, creating symbiosis between the two
How did Chloroplasts Evolve?
Thought to ave been taken up by early eukaryotic cells that already contained mitochondria and created symbiosis between the two
Chloroplast Definition
Green organelles found inside plants and algae
Two membranes
Contain Chlorophyll in their internal stacks of membranes
Carry out photosynthesis
CONTAIN THEIR OWN DNA
Endoplasmic Reticulum Definition
Cell membrane components as well as materials that will be exported out from the cell are made
Golgi apparatus Definition
Receives and modifies and packages molecules made in the ER that will be secreted from cell or transported to another cell compartment
Lysosomes Definition
Intracellular digestion occurs, releasing nutrients from ingested food particles into the cytosol
Peroxisomes Definiton
Use hydrogen peroxide to inactivate toxic molecules
Cytosol Definition
part of the cytoplasm that is not contained within intracellular membranes
Contains both large and small molecules
Site of many chemical reactions
Cytoskeleton and its Filaments
Actin -> contractile forces (large number in muscle cells)
Intermediate -> Strengthen the cell, give shape
Microtubules -> Help pull chromosomes in opposite directions and distribute them into two daughter cells
Eukaryotic Cells are typically ____x the length and ______x the volume of prokaryotic cells
10, 1000
What is a protozoan?
free-living, motile, unicellular organisms
Most are predators
All cells are thought to be descended from a common ancestor, whose fundamental properties have been conserved through evolution
What makes an organism a model organism?
Reproduces rapidly, multicellular but transparent, easier to genetically manipulate
E. Coli as a model organism
- Rapid Reproduction
- Grows in a simple nutrient broth
- knowledge of how cells replicate their DNA came from E. coli studies
Brewer’s Yeast (Saccharomyces cerevisiae) Model Organism
Single-celled fungus that reproduces rapidly
Given us knowledge of the cell division cycle
Arabidopsis thaliana Model Organism
Grown indoors and rapidly
8x the DNA than yeast
Complete genome sequence is known
Drosophila melanogaster Model Organism
Proved that genes are carried on chromosomes
Caenorhabditis elegans (Nematode worm) Model Organism
Genome has been completely sequenced
959 body cells in total
70% of human genes have some counterpart in the worm
In vitro vs. In vivo meanings
In vitro -> in glass
In vivo -> in the living
what is an organoid
a human embryo cell that has been codedinto differentiating into multiple cell types
Why aren’t human used as model organisms
we are very complex
about 2x the genes of a Drosophila
25x the DNA
Mouse can be used instead because almost every human gene has a counterpart in the mouse with similar sequence and function
What is meant by “Survival of the fittest”
Organisms that reproduce with ease will survive better than those that do not
