Chapter 2: Cell Structures and Functions Flashcards
What are the 4 vital functions of an animal cell?
- Protection & Support
- Movement
- Communication
- Metabolism & Energy release
Who first observed and coined the term “cell”?
Robert Hooke
Published book by R. Hooke
Micrographia (1665)
More on microorganisms, protozoa, and sperm; supported the idea of Robert Hooke
Anton van Leeuwenhoek
Proposed the unified cell theory
Theodor Schwann (Zoologist) & Matthias Schleiden (Botanist
Unified Cell Theory:
- Cells are the basic unit of life.
- All living things are composed of one or more cells.
- Cells arise from pre-existing cells through cell division
Who supported the 3rd statement of the unified cell theory?
Rudolf Virchow
Fluid; semi or selectively permeable
Cell membrane or plasma membrane
Regulates what comes in and out of the cell; studded with proteins
Cell membrane or plasma membrane
Phospholipid bilayer consists of?
- Hydrophilic polar head
- Hydrophobic fatty acids tail
Transport mechanism:
- Active transport
- Passive transport
Differentiate active and passive transport:
ACTIVE TRANSPORT
- requires cell’s energy
- moves against against CG
- Small molecules (ions)
PASSIVE TRANSPORT
- naturally occurring; does not require energy
- larger molecules
- moves along the CG
Readily available energy
Adenosine triphosphate (ATP)
Long storage (energy)
Glycogen
Longer storage (energy)
Triglyceride
Movement of molecules from high to low concentration until it is equal across the space (solvent and solute move)
Diffusion
Materials diffuse across the plasma membrane with the help of membrane proteins.
Facilitated transport
Movement of water through a
semipermeable membrane according to
the concentration gradient of water
across the membrane, which is inversely
proportional to the concentration of
solutes.
Osmosis
Other factors that affect particle movement
- Tonicity
- Osmolarity
describes how an
extracellular solution can
change the volume of a
cell by affecting osmosis
Tonicity
describes the total solute
concentration of the solution
Osmolarity
Types of Solutions on which cells are exposed:
- Hypotonic
- Hypertonic
- Isotonic
ECF has lower osmolarity than the cytoplasm; cell swells
Hypotonic
ECF has higher osmolarity than the cytoplasm; cell shrinks
Hypertonic
ECF has the same osmolarity as the cell
cytoplasm
Isotonic
semi-fluid/gelatinous
matrix that houses other
organelles
Cytoplasm
Foundation of cytoplasm
Cytoskeleton
Fluid part of cytoplasm
Cytosol
- ”energy factories”
- ATP synthesis (cellular
respiration) - cristae – folds
- matrix and membranes
Mitochondrion
- site for protein synthesis
- ”tiny dots” in cytoplasm
- attach to ER, NE, etc.
Ribosomes
Endomembrane system:
- Smooth ER
- Rough ER
- Golgi apparatus
- system of internal
membrane - manufacture
carbohydrates and lipids - calcium-ion storage and
drug detoxification
Smooth Endoplasmic Reticulum
- studded with ribosomes
- carry out protein
synthesis - ”intracellular highway”
Rough Endoplasmic Reticulum
- collects, packages, and
distributes molecules that are being manufactured
inside the cell
Golgi Apparatus/
Body/Complex
- membrane-bound sacs
- for transport and storage
Vesicles and Vacuoles
- ”organelle recycling
facility” - hydrolytic enzymes to
destroy pathogens - phagocytosis & exocytosis
Lysosomes
- small, round, membrane-bound
- carry out oxidation
reaction for detoxification - hydrogen peroxide
(H2O2) storage - Safely break down into
O2 and H2O
Peroxisomes
- support and cell shape
for cell motion - network of protein fibers
Cytoskeleton
Cytoskeleton fibers:
- Microfilament
- Intermediate filament
- Microtubules
Cytoskeleton fiber for cellular movement
Microfilament
Mainly structural cytoskeleton fiber
Intermediate filament
Cytoskeleton fiber to resist compression
Microtubules
- ”microtubule organizing
center” - contains a pair of
centrioles - pulling the duplicated
chromosomes to opposite ends of the dividing cell
Centrosomes
- long, hair-like structures
that extend from the
plasma membrane: move
an entire cell
Flagella
- short, hair-like structures
that are used to move
entire cells or substances
along the outer surface of
the cell
Cilia
- plant cell organelles that
carry out photosynthesis
Chloroplast
Components of chloroplast:
- thylakoids stack - granum
- fluid - stroma
- Chlorophyll
- rigid covering that
protects, provides
structural support, and
gives shape to the cell
Cell wall
Information center
Nucleus (DNA = instructions)
Semi-fluid region inside nucleus
Nucleoplasm
Condensed region
Nucleolus
- compartments/
containers in mammalian
cells - may serve as a “genome defense system”
- how the early nucleus formed
Exclusome (2023)
- unicellular algae Braarudosphaera bigelowii
- ”nitrogen-fixing organelle”
Nitroplast (2020)
series of events involving cell growth and cell division that produces
two new daughter cells
The Cell Cycle
2 major phases of the cell cycle:
- Interphase
- Mitotic phase
cell grows and
DNA is replicated
Interphase
replicated DNA and cytoplasmic contents are separated, and the cell divides
Mitotic phase
Every cell except sex cells
Somatic cells
3 parts of interphase:
- G1 phase
- S phase
- G2 phase
- cells’ active at the biochemical level\
G1 Phase (First Gap)
- accumulating the building blocks
of chromosomal DNA and associated proteins
G1 Phase (First Gap)
- accumulating sufficient energy reserves to complete
the tasks of replicating each chromosome in the
nucleus
G1 Phase (First Gap)
- DNA replication proceeds in the
formation of identical pairs of
DNA molecules—sister chromatids - Duplicated centrosomes
S Phase (Synthesis of DNA)
orchestrates the
movement of chromosomes during mitosis
Mitotic spindle (two centrosomes)
- cell replenishes its energy stores
and synthesizes proteins necessary
for chromosome manipulation - Some cell organelles are duplicated
- cytoskeleton- dismantled to provide resources for the
mitotic phase
G2 Phase (Second Gap)
multi-step process during which the duplicated chromosomes are aligned, separated, and move into
two new, identical daughter cells
The Mitotic Phase
2 parts of the mitotic phase
- Karyokinesis/Mitosis
- Cytokinesis
PPMAT; resulting in the division
of the cell nucleus
Karyokinesis/Mitosis
- “cell motion”
- physical separation of the
cytoplasmic components
into the two daughter
cells
Cytokinesis
- Cells are not actively preparing to divide
- quiescent (inactive) stage that occurs when cells exit
the cell cycle
G0 Phase
Examples of cells that stay in the G0 phase:
- mature
cardiac muscle and nerve cells
Haploid cells that are part of the sexual reproductive cycle are produced by this
type of cell division
Meiosis
both forms of division of the nucleus in eukaryotic cells
Mitosis and meiosis
Differentiate mitosis and meiosis:
MITOSIS
- Division: Single
- Type of cells: Somatic cells
- Ploidy: Diploid (two sets of chromosomes)
- Outcome: 2 daughter cells
MEIOSIS
- Division: Double
- Type of cells: Sex cells
- Ploidy: Haploid - one set of chromosomes
- Outcome: 4 haploid cells
Types of cells:
- Prokaryote (bacterium)
- Eukaryote (animal and plant cells)
- simple, mostly single-celled (unicellular) organisms
- lacks a nucleus; or any other membrane-bound
organelles - DNA is found in a central part of the cell called
the nucleoid
Prokaryote
General Structure of a Prokaryote
peptidoglycan cell wall
and many have a
polysaccharide capsule
* flagella - locomotion
* pili - material exchange
* fimbriae - attachment
- membrane-bound
nucleus - numerous membrane-
bound organelles - “true nucleus”
Eukaryotic cells
LUCA
Last Universal Common Ancestor
This phylogenetic tree was constructed by who using data obtained
from sequencing ribosomal RNA
genes?
Carl Woese
three domains:
- Bacteria,
- Archaea
- Eukarya
