5. Cellular biology Flashcards
What is cell theory?
• all living things are made of cell
• cell is the basic unit of lite
• chemical rxns of life take place in cell
• Cells form from pre-existing cells
• Cell carry DNA that is passed to daughter cells
What cell structures do prokaryotes have?
Membrane
Cytoplasm
Genome
Ribosome
What is the fluid mosaic model?
State of the cell membrane and illustrates that it is composed of a phospholipid bilayer with embedded proteins.
What is the function of the nucleus in a eukaryotic cell?
Contains DNA and nucleolus
What are ribosomes composed of?
2 ribosomal subunits
What is the primary function of the rough endoplasmic reticulum (RER)?
Protein synthesis
The RER is studded with ribosomes, which facilitate the production of proteins.
What is the purpose of the smooth endoplasmic reticulum (SER)?
Metabolism and lipid production
The SER is involved in the synthesis of lipids and the metabolism of carbohydrates.
What is the role of the Golgi apparatus in a eukaryotic cell?
Delivery network of the cell; modifies, packages, and distributes proteins and lipids produced in the ER.
What is the purpose of nucleolus?
Site of rRNA production
What folds of the inner mitochondrial membrane called?
Cristae
How do mitochondria replicate?
Mitochondria replicates its circular genome via binary fission.
What is cytosol?
Cytosol is the fluid component of the cytoplasm.
What is cyclosis?
Cyclosis is the flow of cytoplasm facilitated by the cytoskeleton.
What are the functions of vacuoles in animal cells?
Transferring substances in and out of the cell
Storing water and minerals
What do plant vacuoles primarily store?
Plant vacuoles primarily store water and minerals.
What are centrioles made of?
Centrioles are composed of microtubules.
Where are centrioles located?
Centrioles are located in the centrosome.
What is the function of lysosomes?
Lysosomes contain hydrolytic enzymes that break down cellular waste and can cause autolysis.
Which type of cells don’t have centrioles?
Plant cells
What are lysosomes? What is their function?
Membrane bound vesicles containing hydrolytic enzymes. It breaks down stuff and causes autolysis.
What is autolysis?
Autolysis is the self-destruction of a cell.
What is the centrosome?
Region of cell that organizes microtubules and regulates cell cycle
What is the primary function of the cytoskeleton?
Supports cell, maintains shape, and aids mobility
The cytoskeleton is essential for cell structure and movement.
What are the main components of the cytoskeleton?
- Microtubules
- Microfilaments
- Intermediate filaments
These components work together to provide structural support and facilitate movement.
What are microtubules made of?
Hollow rods of polymerized tubulin
Give three examples of structures formed by microtubules.
- Cilia
- Flagella
- centrioles
What are microfilaments primarily made of?
Solid rods of actin
What functions do microfilaments serve?
- Support and mobility for the cell
- Muscle contractions with myosin
- Move materials across plasma membrane
What are intermediate filaments?
Groups of filamentous proteins that withstand great tension
What is an example of an intermediate filament?
Keratin
What is the function of microtubules?
support the cell and allow organelle movement
What is the function of intermediate filaments?
Intermediate filaments provide structural support to the backbone of cell and anchor organelles in place.
What is Simple Diffusion?
Transport of molecules down a concentration gradient passively.
What is Osmosis?
The diffusion of water across a selectively permeable membrane.
Define isotonic.
A solution where the concentration of solute is equal inside and outside the cell.
What happens in a hypotonic solution?
Water moves into the cell, which may cause it to lyse (burst).
What is the result of a hypertonic solution?
Water moves out of the cell, leading to plasmolysis (shriveling).
Fill in the blank: In a hypotonic solution, a cell may _______.
lyse
Fill in the blank: In a hypertonic solution, a cell undergoes _______.
plasmolysis
What is facilitated diffusion?
Passive diffusion of larger and charged particles through protein channels and carriers.
Facilitated diffusion does not require energy input.
What is active transport?
Transport of molecules against their concentration gradient with help of ATP, transport proteins, and carrier molecules.
Active transport requires energy.
What is the role of symporters?
Move ions in one direction.
Symporters facilitate the simultaneous transport of two different substances.
What do antiporters do?
Exchange ions for another.
Antiporters transport two different ions or molecules in opposite directions.
What is a pump in the context of cellular transport?
Energy-dependent carriers (e.g., Na+/K+ pump).
Pumps use ATP to move ions against their concentration gradient.
What is endocytosis?
Uptake of large volumes by engulfing it.
Endocytosis allows cells to intake large particles or fluids.
What are the two types of endocytosis? What are their functions?
- Pinocytosis
- Phagocytosis
Pinocytosis is the uptake of liquids, while phagocytosis is for solids.
What is exocytosis?
Excreting large substances used in cell growth and intercellular signaling.
Exocytosis is critical for the secretion of hormones and neurotransmitters.
What are the stages of the cell cycle?
G1
S
G2
M
What happens during G2 in the cell cycle?
The cell grows and synthesizes protein in preparation for division
What does G1 represent in the cell cycle?
The first gap phase where the cell grows and synthesizes proteins.
What is interphase? In terms of cell cycle?
The phase of the cell cycle where the cell is not actively dividing.
G1, S, G2 phases
What is the S phase in the cell cycle?
The phase where DNA synthesis occurs.
What does M stand for in the cell cycle?
Mitosis or meiosis.
What is a centromere?
The point where chromatids join together
What is a chromatid?
A singular chromosome strand
What is Sister chromatid?
Two identical chromatids
Is a chromatid attached to a centromere by itself considered a chromosome?
Yes
What form is DNA in during interphase?
DNA strands plus histones
What is the result of mitosis?
Produces 2 identical daughter cells in somatic cells
What is are somatic cells?
Non gamete cells
What is karyokinesis?
The nuclear division of mitosis
What are the steps of mitosis?
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
What happens in prophase?
- Chromatin condenses into chromosomes
- Nuclear membrane dissolves
- Centrioles separate and move to opposite sides of the cell
What happens in metaphase?
- Centrioles anchor to the cell membrane with spindle fibers
- Centrioles attach to kinetochore protein of centromere with spindle fibers
- Align chromosomes across metaphase and pate
What happens in anaphase?
- Centromeres split, separating sister chromatids
- Spindle fibers shorten, pulling sister chromatids to opposite sides
What happens in telophase?
- Spindle fibers disappear
- Nucleus forms around each set of sister chromatids
What is the ploidy of each daughter nuclei after telophase in mitosis?
Diploid (2n)
What happens in cytokinesis in animals?
- Organelles are duplicated
- Cleavage furrow takes place
What is cleavage furrow?
Animal cells pinch during mitosis into 2 daughter cells
What happens in cytokinesis into plants?
- Organelles duplicate
- Cell plate forms around each
What is cell plate formation?
It is how plant cells divide by creating a cell wall between two daughter nuclei during mitosis into
What is ploidy?
Number of copies of homologous chromosomes
What are homologous chromosomes?
Chromosomes with same genes but different alleles
What is the ploidy equation?
Number of original chromosomes X ploidy = total number of chromosomes
How is interphase in meiosis different from mitosis?
A chromosome has 4 sister chromatids
How is prophase 1 different compared to mitosis?
It involved crossing over
What is crossing over?
Genetic exchange between chromatids of homologous chromosomes
How does crossing over happen?
- Synpasis forms tetrad
- DNA is cut at chiasmata and exchanged between chromatids of homologous chromosomes
What is synapsis in meiosis?
Process of homologous chromosomes coming together
What is a tetrad in meiosis?
The structure of 2 homologous chromosomes joining together
What is chiasmata?
Location on chromatid where DNA is cut during crossing over
How is anaphase 1 different compared to mitosis?
Disjunction takes place
What is disjunction?
The process of separating homologous chromosomes during anaphase 1
According to what law does disjunction take place? Explain.
Mendelian law of segregation which states that disjunction must occur randomly
What is the ploidy of daughter cells after telophase 1?
Haploid (1n)
