Cells Flashcards
What is a cell?
The basic unit of all living organisms
What is a prokaryotic cell?
It usually belongs to a unicellular organism that lacks membrane-bound organelles, 70s ribosomes, and a has no defined nucleus.
What is a eukaryotic cell?
A cell that possesses a defined membrane-bound nucleus with membrane-bound organelles, 80s ribosomes, and mitochondria.
What is the plasma membrane?
The phospholipid bilayer that encloses an entire cell.
What is a phospholipid?
An amphiphilic molecule that makes up the phospholipid bilayer of membranes in cells.
Why does a flat phospholipid sheet form a sealed sphere in aqueous conditions?
Hydrophobic tails repel water and form a compartment of fatty tails with the phosphate heads facing the aqueous environment.
What does DNA stand for?
Deoxyribonucleic acid.
What does RNA stand for?
Ribonucleic acid.
Which nitrogenous base from DNA is replaced in RNA and with what?
Uracil replaces thymine in RNA.
Which nucleotides are pyrimidines?
Cytosine, thymine and uracil.
Which nucleotides are purines?
Adenine and guanine.
Do ribosomes have a membrane?
No.
Define binary fission.
The asexual reproduction of prokaryotes.
Define cytokinesis.
Division of cell cytoplasm at the end of cellular division.
Define Zygote.
Fertilized ovum (egg cell) before division occurs, contains both male and female pronuclei.
Define gamete.
Mature sex cells, haploid male spermatozoon or female ovum.
Define diploid.
A cell that contains all chromosomes in pairs. Except for X and Y in male cells
Define haploid.
A cell that contains all unpaired chromosomes.
Define Mitosis.
Division of a single cell to produce two genetically identical diploid daughter cells for growth and repair of tissues.
Define Meiosis.
Division of a single cell twice to produce four genetically unique haploid daughter cells for sexual reproduction.
What is the name of the hypothesis where mitochondria and chloroplasts are species of prokaryotes that merged with our ancestors’ cells to develop a mutually beneficial relationship?
Endosymbiosis.
Define gram-positive.
Prokaryote with a single plasma membrane that is enclosed by a multi-layer peptidoglycan cell wall.
Define gram-negative.
Prokaryote with a double plasma membrane with a single-layer peptidoglycan cell wall in between the two membranes.
