Week 2 content: Cells Flashcards
what is a cell
cell are the building blocks of all living organisms
cells can only be created from pre-existing cells, this occurs in interphase, G1, where cells grow, replicate DNA and organelles, preparing for separation
what are the two cell types
Eukaryotes and Prokaryotes
what is a Eukaryotic cell
a type of complex cells that contain a nucleus and organelles contained within a plasma membrane
what is a prokaryotic cell
a small, single-cell organism (bacteria), that lacks a nucleus and membrane bound organelles
what are some cell types in human bodies
- red blood cells
- epithelial cells
- skeletal muscle cells
- nerve cells
name the components and organelles in eukaryotes
(15)
- nucleus
- ribosome
- mitochondria
- Golgi complex
- vacuole
- cytoplasm
- lysosome
- plasma membrane
- centriole
- cilia
- cytoskeleton
- protein fibres
- endoplasmic reticulum (rough and smooth)
- microvilli
what are the different types of protein fibers found in a cell
- microfilaments: smallest and are part of the cytoskeleton, they are important for muscle contraction and cell movement. Made of polymers of actin.
intermediate filaments: found inside cell, responsible for stability and organisation of organelles
microtubules: provide cell shape, help move organelles, separate chromosomes during cell division
what do each of these organelles do
cell membrane:
- a barrier between inside and outside of cell.
- regulates what substances enter and exit the cell
- allows communication between cells
nucleus:
- found within the nucleus envelope
- contains pores in membrane
- contains DNA, genes code for proteins
- nucleolus produces ribonucleic acid
Cytoskeleton: a network of protein fibers that provide structural support and movement.
microvilli: small, finger-like projections found on cells surface, increases SA
mitochondria:
- production of ATP
- contains its own DNA (mDNA)
- mDNA contains 37 genes that code for ATP production
Endoplasmic reticulum:
- smooth: no ribosomes, makes and stores lipids and steroids, makes cellular material, detoxifies, stores calcium for cell signaling
- rough: covered in ribosomes, produces proteins that when released into the lumen (small spaces inside rER) are folded and modified until functional
Golgi complex:
- receives products from rER
- releases products into plasma membrane or out of cell
lysosomes:
- contain digestive enzymes
- have a low pH
- breakdown of damaged cells and bacteria
- lysosomes fuse to cell membrane to eject unwanted components
what is the cell membrane made up of
- lipid membrane made of phospholipids
- proteins
what proteins are found in the phospholipid membrane of cells
- channel proteins allow movement of water substances through the membrane
- integral proteins: span through the entire membrane, from external layer to internal
- peripheral proteins: slightly embedded in membrane
-glycoproteins: made up of a carbohydrate bound to protein (receives messages)
what are examples of integral proteins
- ion channel and carrier proteins: create channels to transport ions and substances
- receptors: communication between cells
- some enzymes: break down substances
- some linker proteins: anchor, provide structural stability
what are examples of peripheral proteins
- some enzymes
- cell identity markers: recognition of your own body’s cell
what are the two categories of membrane transport
passive (doesn’t require energy) and active (requires energy)
what are the seven (7) types of membrane transport
- diffusion
- facilitated diffusion
- osmosis
- active transport
- vesicular transport
- endocytosis
- exocytosis
what is diffusion
- movement of substance from an area of high conc. to an area of low conc.
- does not require energy
- rate of diffusion is influenced by:
- distance,
*size of molecules, *temperatures,
*steepness of conc. gradient (larger conc. gradient = faster diffusion),
*electrical forces within cells (more -ive charge in cells = faster diffusion for positively charged ions)
eg CO2 and diffusion (the product of ATP production) - excess CO2 in cells = high conc. gradient.
- CO2 moves from area of high to low conc. - out of cell
cell interior–> interstitual fluid–> bloodstream –> lungs –> exhaled
what is osmosis
movement of water across cell membrane by diffusion
- area of high conc of solutes –> area of low conc. solutes
- high water levels in cell = low conc. of solutes
- low water levels outside cell = high solute conc.
- even levels of solute conc. inside and outside of cell = no net movement of water
what is facilitated diffusion
ions and polar/ionic molecules cross in or out of cells via channel or carrier proteins
what is active transport
- can transport solutes without conc. gradient
- requires ATP
- involves ion pumps to transport ions such as Na+, K+, and Ca2+
what is vesicular diffusion
use of fluid filled sacks that move material into or out of cell
what is endocytosis
- a type of vesicular transport for entry of material into cell
- cell membrane invaginates and collects molecules
- encloses over molecules creating a sack.
- material is moved into cell
what is exocytosis
- a type of vesicular transport used to remove molecules from the cell
- material is collected and enclosed within a vessel in the cell
- vessel fuses to cell membrane
- cell membrane moves apart to release contents
what happens to human cells in solution?
hypertonic solution: having greater conc. of solutes and less water than another solution. E.g. high conc. of sodium ions outside a cell and low conc. inside the cell cause the cell to release water to dilute the solution outside, causing it to shrink
hypotonic: low solute conc. and more water than another solution. E.g. a cell placed in water = more Na+ ions inside the cell compared to outside and less water
- causes water to move into cell to dilute Na+ ions, causes cell to swell, and potentially burst
isotonic: concentrations of water and ions are the same inside and outside of cell. No net movement, the cell and its environment are at equilibrium.
what solution is used to treat dehydration or used in a saline drip, why?
isotonic solutions
- does not affect the cells volume or structure
- increases the amount of extracellular fluid
what is extracellular fluid
a fluid found outside of cells
what is intracellular fluid. How does it differ from the cytoplasm and cytosol
Intracellular fluid is found inside the cell.
It is essentially the same as the cytoplasm, however, the cytoplasm encompasses all the cell contents within the cell membrane.
the cytosol is the liquid portion of the cytoplasm
what are the major types of cell division
mitosis and meiosis
what is involved in mitosis
division of a parent cell into two daughter cells. Each daughter cell contains the same genetic material as the parent (46 chromosomes, 23 pairs)
what is involved in meiosis
division of a cell into four daughter cells, containing half the number of chromosomes to the parent
this is necessary for reproduction
what are the major phases in the cell cycle (two) in mitosis
Mitotic phase and interphase
breakdown the phases in the cell cycle
Mitotic phase = prophase, metaphase, anaphase, telophase, cytokinesis
interphase = G1, G0, S and G2
draw the phases and what occurs within each phase
interphase
- G2 = growth and centromere replication
- S = DNA replication
- G0 = some cells exit the cell cycle for no further replication
- G1 = the first stage of mitosis, duplication of organelles
mitotic phase
- prophase = chromosomes duplicate and coil, become visible. centrosomes divide and position at opposite ends of cell, spindle fibers begin to extend from each end
- metaphase = chromosomes align along the metaphase plate, spindle fibers attach to kineticore
- anaphase = sister chromatids split and are pulled by microtubules to opposite cell ends
- telophase = nuclear envelope reforms, chromosomes uncoil, nucleoli reappears, indentation in cytoplasm (cleavage furrow)
- cytokinesis = division of daughter cells
what are different cells lifespans
Neutrophils = hours to days
skin cells = 2-3 weeks
what is DNA and what is DNA replication
DNA is the genetic material that codes for the functions of a cell. DNA is made up of different genes, each gene consists of nitrogenous bases grouped into codons (3 bases), and each gene is responsible for coding a certain protein
what is DNA replication
DNA replication is when the parent DNA helicase separates, producing exact copies of its DNA so that each daughter cell produced contains the same information
what makes up a nitrogenous base
on a DNA strand
- adenine
- thymine
- guanine
- cytosine
On RNA strand
- adenine
- uracil
- guanine
- cytosine
what are the mitotic phases (four stages) and cell division phase
- prophase
- metaphase
- anaphase
- telophase
Cell division = cytokinesis
where are checkpoints in the cell cycle (3)
- G2 = cell size and correct DNA replication
- Mitotic phase = chromosomes attachment to spindles
- G1 = DNA damage
what are proteins made up of
long polymer chains of amino acids
Explain the role of proteins in a cell
different cells = different proteins
determine
- molecule transport
- cellular signaling response
- enzyme production –> metabolic pathways
- structural layout of cell
how do proteins produced in the ER get exported outside of the cell
as proteins pass through the ER to the Golgi apparatus and from the Golgi apparatus to the outside of the cell, they are modified.
modified proteins are transported by vesicular transport or progressive maturation to the outside of the cell. Some proteins are transported to lysosomes or plasma membrane
what is the role of proteins outside of a cell?
repair
immunity
pH
energy
fluid balance
what is a genome
what does a gene code for
explain the structural breakdown of DNA in a cell
what are the main components of genes
define each region and its role
what is transcription, where does it occur and what does it produce
what is translation, where does it occur and what does it produce
What are the different types of DNA
what are the components of RNA
what are the four/five nucleic acid bases
what determines the production of certain proteins
what is a codon and an anticodon
what codons codes for stop
what codon codes for start
what is protein synthesis
in protein synthesis, what types of RNA is involved
what are the three main steps in protein synthesis
how is DNA packed
what are the components of a ribosome
what is the purpose of a ribosome
what enzymes are used in protein synthesis and what is their role
when does a protein become functional
what bonds hold amino acids together
