Quiz 1 Flashcards
Cell
Basic building block of organisms
What are the two categories of cells?
- Prokaryotic cells
- Eukaryotic cells
Describe prokaryotic cells
- Unicellular
- Lack membrane-bound organelles
Describe eukaryotic cells
- Membrane-bound nucleus
- Complex structure
- Compartmentalized organelles (e.g., mitochondria, ER)
Phenotype
Organism’s observable characteristics
In 1866, Heckel proposed the Three Kingdoms of Life. What are they?
- Plants
- Animals
- Protists
What is the average cell size of prokaryotes?
~0.4-3 micrometers (diameter)
List the components of prokaryotes.
- plasma membrane
- cell wall
- capsule
- nucleoid
- plasmids
What is the cell wall in prokaryotes made up of?
Peptidoglycan (polymer of amino acids and sugars)
What is the structure and function of capsules in prokaryotes?
polysaccharide layer that promotes cell adhesion to surfaces
What is the defining characteristic of eukaryotes?
Compartmentalization
Nuclear pores
control transport of molecules in and out of nucleus
What do peroxisomes do? Give an example.
Convert toxic byproducts into harmless molecules (e.g., hydrogen peroxide -> water)
Central dogma of biology
Information encoded in DNA is transferred to RNA
RNA directs synthesis of proteins
Describe the process of transcription.
DNA is used as a template to synthesize messenger RNA (mRNA)
In mRNA, _____ is replaced with _____.
Thymine; uracil
Cyanobacteria
group of bacteria capable of photosynthesis
Cyanobacteria possess what two components?
Carboxysomes and thylakoids
What is the function of cyanobacteria?
Carry out photosynthesis
What is the theory of endosymbiosis?
eukaryotic cells originated from a primitive prokaryotic cell
According to the theory of endosymbiosis, the cell membrane invaginated and punched, giving rise to which organelle?
Endoplasmic reticulum
How did the Golgi apparatus form?
Endoplasmic reticulum budded off vesicular clusters that fused together
What event in theory of endosymbiosis led to the evolution of mitochondria?
Ancestral cell engulfed an aerobic prokaryote
* Escaped digestion
* Enabled host cell to use oxygen and generate energy
* Evolved into mitochondria
What symbiont in theory of endosymbiosis led to the evolution of chloroplasts in certain cells?
Cyanobacteria
Surface area
increases six times length squared (6 x l^2)
Explain the relationship between surface area and volume
Surface area - increases six times length squared (6 x l^2)
Volume - increases faster (length cubed (l^3))
As cell size increase, the surface area-to-volume ratio _________.
Decreases
As cell size ________, the surface area-to-volume ratio decreases.
Increases
A ______ surface area-to-volume ratio is better for transporting materials quickly in and out of cell
Large
All living organisms are constructed from _____.
Cells
Cell theory
- All organisms are composed of cells
- Cells are the smallest living things
- Cells arise only from pre-existing cells
Why are most cells small?
Reliance on diffusion of substances in and out of cells
What is rate of diffusion affected by?
- Surface area available
- Temperature
- Concentration gradient
- Distance
As a cell’s size increases, its _____ increases much more rapidly than its _______.
Volume; surface area
What is an example of how larger cells overcome limitations?
E.g., neurons; long, skinny with numerous branches
Explain the history of the cell.
- 1665: Robert Hooke used a simple microscope to look at cork
- Named little rooms he observed “cells”
- Subsequent early studies of cells were conducted by:
—> Matthias Schleiden (1838)
—> Theodor Schwann (1839)
The cell theory was proposed by who?
Matthias Schleiden and Theodor Schwann
Nucleoid
region where DNA is freely bundled
What is one difference between animal and plant cells?
Plants cells contain chloroplasts
What are the three domains of life and their characteristics?
- Bacteria
* Unicellular
* Lack membrane-bound nucleus- Archaea
- Unicellular
- Unique evolutionary history
- Eukaryotes:
- Unicellular and multicellular
- Membrane-bound nucleus
- Includes:
- Fungi
- Plants
- Animals
- Archaea
How do lysosomes contribute to the compartmentalization of eukaryotic cells?
segregate digestive enzymes that function at a very low pH from cytosol
How does mitochondria contribute to compartmentalization in eukaryotic cells?
acidic environment of the two membranes help produce energy in form of ATP
mRNA
type of RNA that represents a copy of DNA coding strand
Explain what happens during translation.
- Codons bind to anticodons located on tRNA
Codon
group of three nucleotides
What is an anticodon and where are is located?
Complementary sequence to a codon. Located on tRNA
