Cell membranes and tissues Flashcards
Forms the outer boundary of the cell
- Composed of a phospholipid bilayer with embedded
proteins
- Functions as a selective barrier, regulating what enters
and leaves the cell through passive and active transport
Plasma membrane
The control center of the cell, housing DNA.
- Surrounded by a nuclear envelope with pores allowing
material exchange with the cytoplasm.
Nucleus
What is chromatin?
contains dna and proteins
Contains chromatin (DNA and proteins) that condense
to form chromosomes during cell division.
Nucleus
The region between the nucleus and plasma membrane,
filled with cytosol (fluid component) and organelles.
- It’s the site of various metabolic activities, housing
important structures like:
Cytoplasm
the powerhouse of the cell, produces
ATP through cellular respiration.
Mitochondria
Sites of protein synthesis, either floating in
the cytoplasm or attached to the rough endoplasmic
reticulum
Ribosome
Rough ER aids in
protein synthesis, while smooth ER is involved in lipid
synthesis and detoxification.
Endoplasmic reticulum
processes, packages, and ships
proteins and lipids
Golgi apparatus
contain digestive enzymes to break down
waste materials and cellular debris.
Lysosome
A network of fibers (microfilaments,
microtubules) that provide shape, support, and assist in
cell movement
Cytoskeleton
Cells carry out metabolic reactions that involve energy transformations.
Cell metabolism
break down
molecules to release energy
Catabolic reaction
build up complex molecules
Anabolic reactions
Reading mRNA by ribosomes to assemble
amino acids into proteins in the cytoplasm
Translation
Cells grow by synthesizing new molecules and
organelles
Growth and Reproduction
is the main energy currency used in cell functions
like muscle contraction, protein synthesis, and active
transport.
ATP
Central to cellular function
Protein synthesis
Protein synthesis involves?
Transcription and Translation
Copying of genetic information from DNA
to mRNA in the nucleus
Transcription
How do cells grow?
By mitosis and meiosis
What does mitosis involve?
Prophase, metaphase, anaphase, telophase, followed by cytokinesis (cytoplasmic division), resulting in two genetically identical daughter cells
How do cells communicate?
Via chemical signals (hormones,
neurotransmitters)
2 stages of cell cycle
Interphase and cell division
Programmed cell death that helps eliminate damaged or
unnecessary cells.
- It plays a key role in development (e.g., shaping tissues)
and maintaining homeostasis.
Apoptosis
allow cells to respond to
external signals, influencing processes like growth,
immune responses, and metabolism
Signal transduction highways
involves DNA mutations, oxidative stress,
and decreased mitochondrial function, leading to
reduced cell function and regeneration capacity
Cellular aging
What does the cell cycle include?
Interphase (G1, S, G2 phases), where the cell grows,
replicates DNA and prepares for division.
And Mitosis, where the nucleus divides, followed by
cytokinesis, where the cell splits into two
A process of growth and division. Most of it
occurs in interphase, where the cell grows and replicates its DNA. After interphase, the cell divides through mitosis, producing two daughter cells, which then enter their own interphase and repeat the cycle
Cell cycle
3 subphases of cells
G1, S, G2
The stage between cell divisions where the
cell performs essential functions, increases in size, and duplicates its DNA and organelles in preparation for division, ensuring that each new cell has the necessary components to function
Interphase
The cell carries out routine metabolic
activities
G1
DNA is replicated.
S
The cell prepares for division
G2
These “resting” cells do not follow the
normal pattern of the cell cycle but instead enter what is
called the
G0 phase
When a parent cell divides into two or more
cells called daughter cells and produces the new cells necessary for growth and tissue repair, ensuring that each new cell maintains the parent cell’s structure and function.
Cell division
Wherein each daughter cell duplicates the
parent cell and used to make exact replicas of themselves.
Mitosis
is the division of a cell’s nucleus into two new
nuclei, each containing the same amount and type of
DNA as the original nucleus.
Mitosis
Divides into four haploid daughter cells and sperm or egg cells are produced instead of
identical daughter cells as in mitosis.
Meiosis
4 phases of mitosis
- Prophase
- Metaphase
- Anaphase
- Telophase
➔ Chromatin condenses to form visible mitotic
chromosomes.
➔ Centrioles divide and move to opposite poles
of the cell.
➔ Spindle fibers extend from centrioles to the
centromeres of chromosomes.
➔ In late prophase, the nucleolus and nuclear
envelope disappear
Prophase
➔ The chromosomes align near the center of the
cell.
➔ Some spindle fibers are attached to
kinetochores in the centromere of each
chromosome.
Metaphase
➔ Chromatids separate and are pulled toward
opposite poles of the cell by spindle fibers,
becoming individual chromosomes.
➔ One set of chromosomes moves toward each
centriole at the poles.
➔ Chromosome movement is assisted by
spindle fibers.
Anaphase
➔ In this phase, the chromosomes complete their
migration.
➔ The chromosomes unravel, becoming less
distinct chromatin threads.
➔ A new nuclear envelope forms from the
endoplasmic reticulum.
➔ Nucleoli reappear.
➔ Cytokinesis progresses, resulting in the
formation of two daughter cells.
Telophase
the division of the cell’s cytoplasm to produce two
new cells. This begins in anaphase and continues through
telophase
Cytokinesis
an indentation in the
plasma membrane
Cleavage furrow
separates extracellular material
from intracellular material and is selectively
permeable—that is, it allows only certain substances to pass through it.
Plasma membrane
Is classified as either
passive or active based on whether or not the cell
expends metabolic energy. During this, the cell does not expend metabolic energy
Passive membrane transport
is the force
required to prevent water from
moving by osmosis across a
selectively permeable membrane
Osmotic pressure
are random movement of molecules
results in net movement from areas of higher
to lower concentration
Diffusion
Is when water diffuses across a
selectively permeable membrane.
Osmosis
is a mediated transport
process that moves substances into or out of
cells from a higher to a lower concentration
Facilitated discussion
is a mediated transport
process that requires energy provided by ATP. Lower to higher concentrations
Active transport
s the movement of larger volumes
of substances across the plasma membrane through the formation or release of vesicles, membrane-bound sacs, in the cytoplasm
Vesicular transport
involves the active transport of an ion, such as Na+, out of a cell, establishing a concentration gradient,
with a higher concentration of the ions outside
the cell
Secondary active transport
occurs when material moves
through the plasma membrane and into the
cytoplasm by the formation of a vesicle
Endocytosis
which means “cell-eating,” solid particles are
ingested and phagocytic vesicles
are formed and therefore important
in eliminating harmful substances
from the body
Phagocytosis
which means “cell-drinking,” is distinguished from
phagocytosis in that smaller
vesicles form.
Pinocytosis
cells release material through a
vesicular transport mechanism
Exocytosis
Is a collection of specialized cells with the same
structure and function
Tissue
4 types of body tissue
(1) epithelial tissue, (2) connective tissue, (3) muscle
tissue, and (4) nervous tissue
is the microscopic study of tissues.
Histology
is the process of removing tissue samples from
patients surgically or with a needle for diagnostic
purposes
Biopsy
Function of epithelial tissue
coverings and linings of the surface
Function of connective tissue
- support
- bone,
ligaments, fat
Function of muscle tissue
movement
Function of nervous tissue
- control
- brain,
nerves, spinal
cord
or epithelium, covers and protects surfaces,
both outside and inside the body
Epithelial tissue
where the cells are exposed and
not attached to other cells, they can be
smooth or folded.
Free surface
Characteristics of epithelial tissue
- Mostly composed of cells.
- Covers body surfaces.
- Regeneration.
- Distinct tissue surfaces
3 distinct tissue surfaces of epithelium
Free, lateral, basal
is between the cells where
cells are attached to other epithelial cells
Lateral surface
is at the base of the tissue
which is attached to a basement membrane
Basal surface
A specialized type of extracellular material secreted by epithelial and connective tissue cells.
Basement membrane
Functions of epithelium
- Protecting underlying structures.
- Acting as a barrier.
- Permitting the passage of substances.
- Secreting substances.
- Absorbing substances.
cells are flat or scalelike.
Squamous
3 types of epithelium based on shapes
Squamous, Cuboidal, Columnar
cells are cube-shaped—about as wide as
they are tall.
Cuboidal
cells tall and thin, column-like
Columnar
Classifications of epithelium
Simple, Stratified, Pseudostratified, Transitional
consists of a single layer of cells,
with each cell extending from the basement membrane to the free
surface
Simple epithelium
consist of adhesive
glycoproteins that bind cells together
Demosomes
similar to one-half of a
desmosome, attach epithelial cells to the
basement membrane
Hemidemosome
Epithelial cells have cell surface
glycoproteins
is a special type of stratified
epithelium. The shape of its cells changes from cuboidal and
columnar to squamous-like when stretched
Transitional epithelium
is a special type of simple epithelium. The prefix pseudo- means false, so this type of epithelium appears to be stratified but is not. It consists of
one layer of cells, with all the cells attached to the basement membrane.
Pseudostratified columnar epithelum
consists of more than one
layer of cells, but only the basal layer attaches the deepest layer to
the basement membrane
Stratified epithelium
a small, specialized contact
region between cells containing protein
channels that aid intercellular communication.
Gap junction
hold cells together and form
a permeability barrier
Tght junctions
is found just below the tight
junction. It is located between the plasma
membranes of adjacent cells and acts as a
weak glue that holds cells together.
Adhesion belt
