Organelle structure AND DNA replication Flashcards
(23 cards)
What are prokaryotic cells
- No nucleus
- Single-celled
- Ex. Bacteria
What are eukaryotic cells
- Nucleus
- Single-celled AND multi-celled
organisms - Ex. Plants, animals, fungi, protists
What are organelles
Organized and specialized structures found within cells. Examples include the nucleus, cytoplasm, vacuole, etc.
What is the nucleus made of and what is the function
It is genetic material (DNA)
surrounded by a membrane. The function is to store genetic material in
eukaryotic cells
What is the vacuole and the function
Water, dissolved chemicals, and
enzymes surrounded by a
membrane layer. They are large in plant cells, small in animal cells. The function is to store water, food, and waste. It also maintains cell water pressure
What does the vacuole do depending on the water
The vacuole swells and shrinks based on how much water is present
What is the ribosome made of and the function
Made of:
- 2 subunits (large and small) that
come together - Small subunit decodes genetic
message - Large subunit activates peptide
bond formation - Each subunit made of ribosomal
RNA (rRNA) and protein
The functions are to produce polypeptide
chains/proteins (long chains of
amino acids) by reading genetic
instructions. It is found on rough ER or free
floating in cytoplasm
What is the mitochondria made of and the function
Made of:
- Double membrane layer
comprising of inner (cristae) and
outer (matrix) membrane
Function:
- Site of respiration
- Breaks down food to produce
energy (in the form of ATP)
What is the endoplasmic reticulum and what is the function
Made of:
- Complex network of folded
phospholipid bilayers. Membrane
bound spaces are called cisternae
Function:
- Rough ER: ribosomes present on
the outer surface. Produce
proteins for export to the cell - Smooth ER: no ribosomes
present. Produce fats/lipids and
metabolise toxins
What is the golgi apparatus and the function
Made of:
- Complex network of folded
phospholipid bilayers. Membrane
bound spaces are called cisternae
The function is to store, packages, and export
proteins and lipids to the outer
membrane and beyond
What are lysosomes and the function
Made of:
- Phospholipid bilayer filled with
digestive enzymes
Function:
- Engulf and breakdown worn out
organelles, food particles, or
invading viruses and bacteria
What is the cell membrane made of and the function
It is made of a phospholipid bilayer with
embedded proteins. The function is to protect the inside of the cell
from exterior factors. It also controls the movement of substances into and out of the cell
What is the fluid mosaic model
The fluid mosaic model describes the
fluid and flexible nature of the cell
membrane and the components it is
made from
- The different components, such as
proteins, cholesterol, and
phospholipids float laterally in the
membrane - Cholesterol helps regulate
membrane fluidity
What is the cell wall and the function
It is made of cellulose (carbohydrate) and located outside the cell
membrane. The function is to provide structural support
- Protects plant cell and maintains
its shape
- Protects the cell from high
internal water pressure (prevents
cell from bursting)
What is the cytoplasm and the function
It is made of sissolved substances (water, salt,
etc.)
- Gelatinous liquid where all the
organelles float in
The function is to store molecules (enzymes and
nutrients)
- Allows waste products to be
transported out of organelles and
the cell
What are white blood cells and the function
White blood cells have lots of
lysosomes (recall: break down
food, bacteria, viruses) as they are
disease-fighting cells that protect
our body from infection
What are red blood cells and the function
Red blood cells are disc shaped
to maximise their oxygen-carrying
capacity (increased surface area)
while allowing them to squeeze
through narrow blood vessels
What is DNA
Deoxyribonucleic acid (DNA) is a
double-stranded helix made of chemical
building blocks called nucleotides
- Nucleotides are made of:
- Sugar (deoxyribose)
- Phosphate
- Nitrogenous bases (adenine (A),
thymine (T), guanine (G) and cytosine
(C))
What is complementary based pairing
The complementary
base-pairing rules states that:
- Adenine (A) always bonds
with thymine (T) - Cytosine (C) always bonds
with guanine (G) - Since each base can only pair
with one other, we can preserve
all the genetic information during
DNA replication
What is DNA replication
DNA contains all the instructions needed for life processes
- New cells receive a full copy of all the genetic information using
DNA replication
What is the purpose of DNA replication
Purpose of DNA replication is to replicate the cell’s DNA in preparation
for cell division (mitosis). Replicated DNA is passed on to daughter cells,
ensuring the new daughter cells carry out the same function as parent
cells
- The daughter cells are genetically identical to the parent cells
- DNA replication must occur before mitosis
What is the process of DNA
- DNA helicase (enzyme) unwinds the DNA strand by breaking the
hydrogen bonds holding the bases together. Nitrogenous bases are now
exposed - New nucleotides are brought in.
The exposed nucleotides can now
bond with the new nucleotides
according to the base pairing rule.
This is done by an enzyme called DNA
polymerase
- Another enzyme called DNA
primase provides the ‘guiding’
information for DNA polymerase to
attach - At the end of the process, two
new double-stranded DNA
molecules are formed that are
exact copies of the parent strand.
The replication process is called
semi-conservative: each new DNA
molecule has one strand from the
original DNA and one entirely
new strand created by DNA
polymerase
Factors affecting DNA replication
Any factors that affect enzymes involved (ex. temperature, pH,
co-factors, inhibitors)
- Availability of free nucleotides for DNA polymerase to attach
- DNA replication occurs only in S phase of cell cycle