Cell Theory
Who are the three main scientists credited for developing the Cell Theory?
Theodor Schwann, Matthias Schleiden, Rudolf Virchow
Which organelles are responsible for cell maintenance?
Lysosome, peroxisome, vacuole
The presence of membrane-bound organelles and true nucleus.
What are the two types of cell division in eukaryotes?
Mitosis and meiosis
Distinguish active and passive transport.
What are the three tenets of classical cell theory?
1. All organisms are made up of cells
2. Cells are the basic unit of life
3. All cells come from preexisting cells
Cell wall, large central vacuole, chloroplasts/plastids
Which prokaryote gave rise to an oxygen-rich atmosphere?
Cyanobacteria
What does G2/M checkpoint checks?
correct replication of DNA during S phase and integrity of DNA
What is the role of ATP in active transport?
ATP provides the energy needed for active transport, as well as the phosphate group necessary to change the shape of carrier proteins.
Why does the Cell Theory support the idea that all living things share a common origin?
Because according to it, all organisms are made up of cells, and cells come from preexisting cells, which suggests that all organisms share a common cellular ancestor
How do the smooth ER and rough ER differ in structure and function?
Rough ER has ribosomes attached and helps in protein synthesis; Smooth ER lacks ribosomes and is involved in lipid synthesis and detoxification
Why is binary fission the most common mode of reproduction for prokaryotic cells?
Because prokaryotes do not have a nucleus, so they cannot undergo nuclear division like mitosis and meiosis
Why do gametes need to be haploid?
So they can restore the diploid number during fertilization or the zygote can have the correct number of chromosomes
A freshwater plant cell is placed in saltwater. Predict and explain the outcome.
The plant cells will lose water and shrink because the saltwater is hypertonic compared to its internal environment.
Why are viruses not considered "alive" based on the cell theory?
1. They are not composed of cells
2. They are obligate intracellular parasites
3. They do not have both DNA and RNA
How are mitochondria and chloroplasts similar, and how are they different?
Both have double membranes and their own DNA and ribosomes. Mitochondria produce ATP through cellular respiration, while chloroplasts produce glucose from photosynthesis.
Why do both prokaryotic and eukaryotic have ribosomes?
Ribosomes are essential to create proteins needed to carry out various cellular functions
Why does meiosis, but not mitosis, contribute to genetic variation?
Because of several events such as crossing over and independent assortment, which are not present in mitosis
How do endocytosis and exocytosis differ in terms of bulk transport?
Endocytosis brings substances into the cell by forming vesicles from the membrane, while exocytosis expels substances from the cell using vesicles that fuse with the membrane.
If a new type of microscope revealed structures smaller than cells, would this contradict the Cell Theory? Why or why not?
No, it does not contradict the cell theory. The size does not matter; as long as the structure checks out the tenets of cell theory, they can be considered alive.
A muscle cell has unusually high numbers of mitochondria. Explain the main reason why.
The muscle needs a lot of ATP in order to contract/move.
Explain how eukaryotic cells evolved.
Ancestral eukaryotic cell -> endosymbiosis with aerobic bacterium -> evolves to mitochondrion -> endoymbiosis with photosynthetic bacterium -> evolves to chloroplasts
Why is each stage of the cell cycle prerequisite to the next?
The events in one stage prepare the cell for the processes in the following stage
Why does facilitated diffusion require carrier or channel proteins while simple diffusion does not?
Because facilitated diffusion moves molecules that are too large or polar to pass directly through the lipid bilayer, so they need transport proteins.