Chapter Five Flashcards
4 tenants of cell theory
- cells are the fundamental units of life
- All organisms are composed of cell
- All cells come from pre-existing cells
- Modern cells evolved from a common ancestor
What does cell theory lead us to know?
Functions of all cells are similar
Life is continuous
Origin of life had to do with cells
Why are cells the fundamental units of life?
They are able of independent existence, and can carry out the vital functions of life.
How do Prokaryotes differ from Eukaryotes?
prokaryotes don’t have nucleus or membrane enclosed organelles
Eukaryotes are 10x larger than prokaryotes
prokaryotes are always single celled, while eukaryotes can be single or multi
what is the cell wall and what does it do?
rigid, outside of the cell membrane
determines the cell’s shape and provides support
{(bacterial cell walls contain peptidoglycan
further outside that is the outer-membrane)
only in prokaryotes}
give definition of a membrane, its composition, it’s function, and its characteristics.
It is the boundary of the cell, and it is composed of a phospholipid bilayer hydrophilic heads hydrophobic tails, with proteins inside of it.
Its function is for protection, separation and its proteins allow adherence/binding/communication to other cells
characteristics of the membrane include being similar in all cells and being selectively permeable
define nucleoid, where is it and what cell has it?
nucleoid is a region of the cell where the DNA is located in a prokaryotic cell
define cytoplasm and explain its importance
jelly-like substance important to every cell
functions to house and maintain an optimal environment for the cellular organelles
area where the rest of the cells contents are
what are the functions of ribosomes and compare them in prokaryotes and eukaryotes.
they synthesize proteins
eukaryotic are similar to prokaryotic ribosomes but eukaryotes are bigger
they consist of rRNA (ribosomal RNA) and more than 50 protein molecules
(about 25 nm in eukaryotes)
define the outer membrane, and where it is found.
it is an additional phospholipid membrane found outside the peptidoglycan layer technically apart of the cell wall
what is a capsule? Is it present in all prokaryotic cells or eukaryotic cells?
slimy (outermost) layer, made of polysaccharides that help protect the cell, present in some prokaryotic cells.
What is pili where are they found and what do they do?
hairlike structures projecting from the cells surface, that help bacteria to adhere to other cells
present in some prokaryotic cells
What is the cytoskeleton in prokaryotic cells?
it is a protein filaments structure
are important for cell division
movement
maintaining the cell shape
what is the endomembrane system (inside the membrane) and what is it composed of? (6 organelles)
interconnected system of membrane-enclosed compartments
1. Cell membrane
2. Nuclear envelope
3.ER
4.Golgi apparatus
5.Lysosomes
6.vesicles
what are vesicles and what do they do?
they are tiny membrane surrounded structures that shuttle substances between various components using the cytoskeleton
What is the nucleus and what is important about it?
it contains most of the DNA of the cell and is usually the largest
- Site of ribosome assembly
- Site of DNA replication
3.Site where gene transcription is turned on/off
Define nucleolus, where is it and what does it do?
it is within the nucleus and assembles the ribosomes
is about 1.5um long
what are some organelles that can be in prokaryotes? (four just prokaryotic / six both E and P)
1.cell membrane (both E and P)
2. Cytoskeleton (both E and P)
3.cytoplasm (both E and P)
4. Ribosomes (both E and P)
5. Cell wall (both E and P)
6. Flagella (both E and P)
7. outer membrane
8. Capsule
9. Pili
10. nucleoid
What is the nuclear envelope and what is its purpose?
it is a double membrane surrounding the nucleus
it uses pores to control the movement of molecules that go in and out
What is the endoplasmic reticulum?
it is the network of membranes in the cytoplasm that have a large surface area
What is the rough ER?
Explain its purpose and characteristics.
it is part of the ER and it has ribosomes attached which synthesize amino acids through translation.
the newly made proteins (to be used in the endomembrane system) enter the RER lumen and are modified, folded, and transported elsewhere
What is the smooth ER?
Explain the functions and characteristics.
a part of the ER that contains no ribosomes,
its purpose is to chemically modify small molecules, like drugs, pesticides
it is also the site of glycogen degradation in animal cells
it synthesizes lipids, and steroids, and also stores calcium ions
What is the Golgi apparatus?
explain the characteristics and functions.
is flattened sacs (cisternae) and small vesicles and is near to the ER
it receives proteins from the ER through vesicles and modifies them further
it concentrates, packages and stores proteins
in plant cells, it syntheses polysaccharides for cell wall (cellulose)
What is phagocytosis, and what is formed as a result?
it is the process of ingesting particles or other cells into a cell, which forms a phagosome
What is a lysosome?
they contain digestive enzymes that hydrolyze (hydrolysis) macromolecules into monomers
What are the two types of lysosomes?
Primary lysosomes - originate from the Golgi apparatus
Secondary lysosomes - are primary lysosomes that are fused with phagosomes
what is exocytosis?
ejecting wastes from the cell
what is a mitochondria and what is it functions and characteristics?
an organelle that converts chemical bond energy into a usable form - energy rich ATP
- two membranes, outer and inner
- *the inner membrane folds inward to form cristae, which creates a large surface area for proteins involved in respiration
- the mitochondrial matrix contains enzymes, DNA, ribosomes
- cells that require a lot of energy have the most mitochondria
What are plastids, where are they found? What are some examples?
double-membrane organelles which are found in the cells of plants and algae. ( plants and protists only)
eg. chloroplasts
What are chloroplasts, where are they found and what are their functions?
organelle where photosynthesis is done
1. have a double membrane
2. the inner membrane forms thylakoids which contain 3.chlorophyll and other pigments that harvest light energy
what are peroxisomes, which cell has them and what do they do?
they break down the toxic by products of metabolism like H2O2 and only eukaryotic cells have them
What are glyoxysomes and what cells are they found in?
they convert lipids to carbohydrates for growth, only found in plants
What are vacuoles, where are they found and what can they do?
they are found in plant, few animal, and protist cells
they provide structure for plant cells - water enters vacuole by osmosis, creating turgor pressure
it can store waste products and toxic compounds, which can deter herbivores
stores anthocyanins (pink and blue pigments) in flowers and fruits that attract pollinators
in seeds, they can have digestive enzymes to hydrolyze stored food for early growth
What is the cytoskeleton in eukaryotes, what does it do and what are the three components (MIM)
it supports and maintains cell shape, hold organelles in place, moves organelles
it is involved in cytoplasmic streaming, and interacts with extra cellular structures to hold the cell in place
three components are microfilaments, intermediate filaments, and microtubules
What are cilia and what are they apart of?
they are apart of the cytoskeleton specifically the microtubules, that appear in the hundreds on one cell that move stiffly to propel cell or move fluid over it
What are flagella and what cells are they found in?
they are part of the cytoskeleton and are long, usually one or two present that help the cell swim
Found in prokaryotes and eukaryotes
what are plant cell walls
cellulose fibers embedded in other polysaccharides and proteins
provides rigid flexible support
barrier to disease causing organism
contribute to plant form as cells expand
what is a plasmodesmata and what is it an example of?
cell membrane-lined channels that connect adjacent plant cells, example of an extra cellular structure in plants
what is the extracellular matrix?
What does it do?
it is composed of fibrous proteins (collagen) gel-like proteoglycans (glycoproteins) and other proteins
surrounds animal cells, holds cells together in tissues
contributes to properties of bone, cartilage and skin etc
filters materials passing between different tissues
orients cell movements in development and tissue repair
plays role in chemically signaling
how did the endomembrane system and the nucleus originate?
from inward folding of the cell membrane in prokaryotes
Advantages of enclosed compartments (organelles) in cells?
there is a concentration of chemicals, and the chemical reactions proceed more efficiently
what is the endosymbiosis theory?
the theory that mitochondria and plastids arose when one cell engulfed another after living / benefiting from each other
What was the OG mitochondria?
aerobic bacteria
What was the OG chloroplasts?
photosynthetic bacteria
What are six pieces of evidence for endosymbiotic theory?
- they are similar in size, shape and membrane structure
- there is a double membrane surrounding the engulfed cells now
- Mito/Chloro reproduce by binary fission
- there is similarity in photosynthetic pigmentation of chloroplasts and cyanobacteria
- They have their own DNA, RNA, and ribosomes
- there is a close relationship in DNA sequence analysis
What is one way to determine an organelles function?
to use a drug to inhibit (stop) structure or process then observe
this is inhibition
why are cells so small?
because their size allows them to have a large SA to V ration which in turn allows for quick exchange of materials
As the cell volume increases so does the need for chemical activity increases, and the need for moving materials increases
Light Microscope?
using light it visualizes the cell shape and size and some internal structures
what are the four structures all cells have?
- a cell membrane
- DNA
- Cytoplasm
- Ribosomes
