Cell Structures and Functions Flashcards
“Principal’s Office”
Houses DNA
chromatin phase-loose DNA
chromosome phase-tightly packed DNA
Nucleus
Has Pores, protects nucleus, Double Membrane (phospholipids) (one side is hydrophilic and one side is hydrophobic)
Nuclear membrane
“Photocopier”
Makes copies of DNA
Nucleolus
Holds cell together, Keeps organelles in place
Cytoplasm
Protects and supports cell
cell membrane
Not organelles, Make proteins
Ribosomes
2 types of ribosomes
Free and bound
Make proteins that stay within the cell
Free ribosomes
Make proteins that will leave the cell
Bound ribosomes
The endoplasmic reticulum is composed of small tubes called _________
cisternae
Helps with the synthesis of lipids, phospholipids, and steroids, Helps break down carbohydrates (ex. Glycogen ((stored sugar)) to Glucose), Helps to detoxify blood (Liver cells = Lots of ____)
Smooth Endoplasmic Reticulum (SER)
Helps with protein synthesis (provides a H2O free environment for protein folding), Ribosomes are bound to the outside and deposit proteins inside as it is made by the ribosome
Rough Endoplasmic Reticulum
Modifies proteins by attaching sugars (called Glycoproteins)
(It’s like a gift wrapping to disguise the protein for export through the cell membrane), composed of flattened tubes called cisternae
Golgi Apparatus
Act like the “stomach” of the cell, Involved in digestion and recycling (autophagy), Full of digestive enzymes (lysozomes), Composed of phospholipid bilayer
Lysosomes
Act as “closets” for storage of materials
Various types exist (food, contractile, central)
Vacuoles and Vesicles
The process of bringing something into the cell
Endocytosis
Process of cell “eating”
Phagocytosis
The process of cell “drinking”
Pinocytosis
Involved in making energy by the performing the process of cellular respiration, Has its own DNA, Has cristae (folded inner membrane) that increases surface area for making energy, _________ matrix has ribosomes and is the site for the Kreb’s Cycle of Cellular Respiration, Evolutionarily significant
Mitochondria
Site of photosynthesis in plants and algae, They are a type of plastid (any of a class of small organelles containing pigment or food.), Has its own DNA ribosomes and enzymes (ATP synthase)
Chlorophyll
Site of light reaction of photosynthesis (ATP from reaction will be used as energy for making sugar in Calvin Cycle)
Thylakoid
Stack of thylakoids
Grana
Watery space between thylakoids and outer membrane (site of Calvin Cycle of Photosynthesis)
Stroma
Proposed that prokaryotes came to live in a symbiotic relationship (the smaller living inside the larger), Eventually these prokaryotes evolved into eukaryotic cells over hundreds of thousands of years
Endosymbiont Hypothesis
Benefits of a smaller cell living inside a larger
Larger gains energy
Smaller gains protection
Helps support and protect the cell, Keeps inner organelles organized, Helps with motility, Composed of various sized protein fibers, Composed of microtubules
Cytoskeleton
What is motility?
cell movement
Large hollow tubes, Composed of tubulin protein, Main function is for support and movement, Help guide movement for organelles
Microtubules
Anchor during cell division, made of microtubules
Centrosomes/centrioles
“Tow ropes”, Used to move chromosomes during mitosis or meiosis, made of microtubules
Spindle fibers
Help with cell movement through wavelike movements
Cilia
Help with cell movement, Fewer than cilia and longer in length, Undulating (whipping) movement
Flagella
Smallest structures in the cytoskeleton, Solid rods, Composed of actin or myosin protein, Provide a “pulling force”, Abundant in muscle tissue
Microfilaments
For protection and durability (holding up plant structure)
Cell wall
Primary cell wall composition
cellulose sugar
Middle lamella composition
Pectin sugar (“Super glue” between cell walls that hold them together)
Secondary cell wall composition
cellulose sugar
Outer protective “skeleton” of the cell plasma membrane in animal cells
Also functions in communication with other cells (use glycoproteins to communicate)
Composed mostly of glycoproteins and glycolipids
Extracellular matrix
Help to hold cells together so they may work together
Some are tunnels for cell to cell communication
Cellular Junctions
Composed of cells
Responds/adapts to environment
Uses energy
Grows and reproduces
Characteristics of a living thing
Said to be selectively permeable, Phospholipids make up the majority of it
cell membrane
Meaning of cell membrane being selectively permeable
Selects what materials enter or exit the cell through the membrane
Membrane also helps to regulate control of homeostasis (stable internal environment) by controlling entry and exit of certain molecules
These molecules are said to be amphipathic (have a hydrophobic and hydrophilic region)
Phospholipid
These molecules created bi-layer and the structure is held intact by the presence of water inside and outside the cell
Phospholipid
Remember proteins fold into 3D structures and that proteins are composed of amino acids that have water _______ and water ________ regions)
loving, fearing
Two types of membrane proteins
integral, peripheral
Types of membrane protein, Run completely through the bi-layer from outside to the inside, These function in the transport of molecules and for stability (help maintain integrity of the structure)
Integral
Type of membrane protein, Located on 1 side of the membrane (do not extend into the bi-layer of the membrane), Act as sites for attachment of the cytoskeleton
peripheral
Functions of membrane proteins?
Transport (Move food, water, etc across membrane), Act as enzymes (control metabolic processes), Cell to cell communication and recognition (so cells can work together in tissues), Intercellular junctions (for “stitching” together to make tissues), Attachment points to the cytoskeleton and extracellular matrix
This molecule helps keep the membrane of all cells flexible
Cholesterol
Helps to keep the membrane of plant cells from freezing solid in very cold temperatures (like the Tundra)
Cholesterol
Cell membrane characteristics as a moving puzzle because all pieces can move laterally (from side to side)
Fluid Mosaic Model
______ and ____ (both gases) diffuse across the wet phospholipid bilayer (example of diffusion)
CO2 and O2
_____ (charged particles) and water move through proteins (hence the name transport protein)
Ions
Operates upon an established [] gradient, Materials flow from high [] to low [] until equilibrium is reached, This is how a majority of materials are transported into the cell (requires no energy)
Diffusion
Water always flows from hypotonic to hypertonic until isotonic (name of process)
osmosis
Very little
Hypo
A lot
Hyper
Referring to water
Tonic
Pure water is _________. (hypertonic, hypotonic, isotonic)
hypotonic
Water molecules ______ stop moving across the membrane even when in isotonic state
never
Condition when there is plenty of water in the plant cell (plant is rigid and stiff)
Turgid
Condition when there is not enough water in the plant cell (limp and wilted)
Flaccid
When the cell membrane rips away from the cell wall killing the plant cell
Plasmolysis
Represented by the Greek symbol psi-Ψ
Water Potential
Water’s ability to perform work while passing through the cell membrane
Water Potential
Water moves from high potential (_______) to low potential (________)
hypotonic, hypertonic
The meaning of facilitate
to help
Is a type of diffusion, The movement requires the help of a transport protein, Does not require energy to occur (Example: Calcium)
Facilitated diffusion
Requires energy, Moving material against the [] gradient
Examples: Proton pumps, Na+/Ka+ pumps of the nervous system
Active Transport
Attaching phosphorus to an inactive ATP to make it active
Phosphorylation
Two types of large molecule transport
Exocytosis, endocytosis
Two types of endocytosis (cell eating and drinking)
Phagocytosis and Pinocytosis
Main purpose of reproduction by cells
propagation (maintaining) of the lineage
the cell that divides into 2 daughter cells
parent cell
The parent cell divides into 2 genetically identical __________ _______
daughter cells
The daughter cell are identical to each other and the previous __________ cell
parent
The cells growing and being able to perform its adult functions
maturation
The cell cycle is necessary for normal _________ (as in the size of organs) and _________ (of existing structures)
growth and repair
The entire genetic material (DNA) for an organism or cell
genome
Can genomes vary?
Yes they vary from species to species.
The genome length for humans is about ___ m or ____ ft per cell.
2m or 7ft
The two different states of DNA
chromosomes and chromatin
Chromatin can be moved around to find the gene segment of interest for __________ ____________.
protein synthesis
Chromosomal content of somatic cells is ___ or ______.
2n or diploid
Half (in terms of chromosomal content) is referred to as _______ or __.
haploid or n
How many chromosomes do human cells have?
46
The proteins that help DNA coil up (condense) to form the chromosomes needed for division
histones
means portion (ex. chromatid)
tid
Half of a duplicated chromosome
sister chromatids
The two halves of sister chromatid are held together at the _______ (means center unit)
centromere
The centromere is a group of _________.
proteins
This process refers to ordinary cell division (Parent cell and daughter cells are exactly alike genetically). Involves only one division after replication occurs in the synthesis phase)
Mitosis
Cells spend 90% of their existence in this phase
interphase
3 parts of interphase
G1, Synthesis, G2
First part of interphase. Primary or first growth. This is ordinary, everyday growth, activity, or repair of the cell. First checkpoint (called “point of no return”) is the barrier to the rest of the cycle
G1
Second part of interphase. The DNA replicates or is synthesized during this phase. In humans we go from 46 chromosomes “2n” to 92 chromosomes “4n”
Synthesis
Third part of interphase. Secondary or second growth. The cell and organelles mainly enlarge or replicate. Second checkpoint occurs after this part. Second checkpoint asks “do we have everything for 2 cells? If yes, the proceed to dividing, if no then make what is missing”
G2
Means “nucleus division” (First divide the DNA; then secondly the cytoplasm.)
Mitosis
Four parts of mitosis
Prophase, Metaphase, Anaphase, Telophase (PMAT)
1 step in mitosis. Nucleus envelope is broken down and rearranged to make the spindle apparatus. The chromatin condenses to form X shaped chromosomes (2 chromatids). The centrioles move toward the poles (In animal cells only, plant cells use the cell wall)
Prophase (“pro” means first)
2nd step in mitosis. The replicated chromosomes line up on the metaphase plate (middle of cell). The spindle apparatus attaches to the kinetochore (a part of the centromere) and centrioles (the anchors). Third checkpoint occurs here. (Are all the chromosomes attached and lined up and ready to “divide/separate” or “segregate”?)
Metaphase (“meta” means middle)
3rd step in mitosis. Replicated chromosomes are pulled apart into sister chromatids and each chromatid moves toward opposite poles of the cell. The spindle apparatus is being broken down as the two sister chromatids are “walked” toward the poles by the motor protein using ATP.
Anaphase (“ana” means separate)
4th step in mitosis. The nuclear envelope is rebuilt by using broken down spindle apparatus pieces. The chromatids begin to de-condense back to their chromatin stage. A cleavage furrow (indent) begins to form using actin and myosin microfilaments
Telophase (“telo” means last)
The cytoplasm and cell organelles are separated to produce two daughter cells. This is the division of the cytoplasm.
Cytokinesis (cleavage means “split”)
Occurs before G1. The cells are tired and take a brief break and rest.
G0 (Zero growth phase)
These structures are formed from the broken down cytoskeleton and nuclear envelope (recycled). The construction starts at the centrosome (where the centrioles are) and works toward the chromosomes. They attach to the replicated chromosomes. Motor protein “walks” the sister chromatids toward the opposite poles (ends) using ATP by phosphorylation. Non-kinectochore spindles are used to “push” the poles farther apart and help produce the cleavage furrow.
Spindle Apparatus
Plant cells do not have centrioles because they have ______ _______ to anchor to.
cell walls
The new cell wall “______” develops, using small segments of cellulose, instead of a cleavage furrow.
Plate
This is the process of Reproduction/Replication in prokaryotes (bacteria). DNA replication (S phase) starts at the “origin” and works around the entire singular circular chromosome, this results in two identical chromosomes in the nucleoid region. This is followed by producing a cleavage furrow (cytokinesis) to produce 2 new cells that are referred to as clones. The cleavage furrow is produced using actin and myosin microfilaments.
Binary Fission
How is Binary Fission related to mitosis in terms of evolution?
Binary Fission would have evolves into Mitosis as the DNA content increased dramatically and also used the endosymbiont hypothesis occurred to produce “organelles.” The two major steps are the same: synthesis and division.
Regulation is crucial for normal _______ and _____________.
growth and development
Regulation ______ for each different type of cell.
varies
molecules that regulate/control the cell cycle
cyclins
Stopping points to make sure everything is correct before going on to the next phase
check point
It is at the end of G1 (Called the Restriction point) “point of no return”
First checkpoint
It is at the end of G2 (Do we have 2 sets of DNA and 2 sets of organelles?)
Second checkpoint
It is at the end of metaphase (Are all the replicated chromosomes in the middle of the cell and are they ALL attached to the spindle fibers?)
Third checkpoint
Cell division is a huge E consuming process, so rest is required for the cell.
G0 (resting state)
Abnormal cell growth
Cancer
No __________ exist within cancerous cells, so there is no density-dependent inhibition.
checkpoints
Cancer starts with transformation of the DNA (________) in a cell
mutation
means Abnormal growth
tumor
Usually not deadly-easy to cure by removal of the tumor (It is encapsulated-like a tennis ball.) (This kind is non-invasive)
Benign
It can be deadly. Normally treated with chemotherapy, radiation, or surgery. (means “the crab”) (It is invasive. It grows between cells destroying the tissue.)
Malignant
