Basics of the Cell Flashcards
What are the cell’s three principal parts?
cell membrane, cytoplasm, nucleus
a semi-fluid substance consisting of mostly water and also containing many dissolved solutes
cytosol
includes the cytosol and all the organelles
cytoplasm
specialized structure that have characteristic shapes and perform specific functions for a cell
organelles
what are the specific functions the organelles perform?
cell growth, maintenance, and reproduction
organelles that are paired cylinders arranged at right angles to one another.
centrioles
what are centrioles made up of
microtubules
what do centrioles play a role in
spindle fiber formation
tiny spheres, consisting of two subunits
ribosomes
the large subunit is ___ and the small subunit is ___
60S and 40S
What are ribosomes associated with
the rough endoplasmic reticulum
what’s another name for ribosomes
protein factories
why are ribosomes sometimes referred to as protein factories
because they are the site of protein synthesis within a cell
a network of membranes that form flattened sacs or tubules
Endoplasmic Reticulum
What does the ER do as a whole?
transports substances, synthesizes molecules, detoxifies chemicals, and releases Ca2+ involved in muscular contractions
part of the ER that is continuous with the nuclear membrane. Its outer surface is studded with ribosomes
Rough ER
part of the ER that extends from the rough ER to form a network of membranous tubules
smooth ER
several membrane sacs that are flattened and stacked
Golgi Body
other words for the Golgi Body
Golgi Apparatus or Golgi Complex
What is the principle function of the Golgi Body
to modify proteins, then sort and package the proteins into vesicles for transport either within the cell or to the extracellular space via exocytosis
the main site of digestion within the cell
Lysosomes
tiny vesicles that form from the Golgi body and contain powerful digestive enzymes
lysosomes
what are the powerful digestive enzymes that lysosomes contain called
acid hydrolases
What is cellular digestion used for
to break down intracellular components and digest unwanted extracellular substances that were brought into the cell
Does the mitochondria have a single or double membrane
double membrane
what does the inner mitochondrial membrane look like
Numerous folds
what does the outer mitochondrial membrane look like
relatively smooth and straight
What is the space between the inner and outer membranes of the mitochondria called
intermembrane space
Where is most of the cell’s ATP synthesized
Mitochondria
a network of several kinds of protein that extend through the cytosol, providing a structural framework for the cell and aiding in cellular movement
Cytoskeleton
What are the proteins included in the cytoskeleton
microfilaments, intermediate filaments, and microtubules
numerous, short, hair-like projections that extend from the surface of a cell and function to move material along the cell’s surface
cilia
Does cilia move liquid/particles along the surface of the cell or into the cell
along the surface of the cell
similar to cilia, but are singly and much longer
flagella
what is the role of flagella
moving an entire cell
what is a natural occurring example of flagellum in the human body
tail of the mature sperm
where are flagella commonly seen
in bacterial cells
what is the most prominent feature of a cell
the nucleus
which organelle houses the cell’s hereditary material
nucleus
cells that have more than one nucleus
multinucleated cells
what are the two types of multinucleated cells
skeletal muscle cells and anucleatic cells
what is a anucleatic cell
a cell without a nucleus
what is the membrane like around the nucleus
a double membrane
what is the double membrane around the nucleus called
the nuclear envelope
what are the channels that the nuclear envelope is perforated by called
nuclear pores
specific region within the nucleus where ribosomal subunits are synthesized
nucleolus
where are chromosomes housed
the nucleus
What are somatic cells
“body cells”
Every cell in our body is a somatic cells except for which two?
Germ cells and gametes
how many pairs of chromosomes does a human somatic cell have
23 pairs
specialized cells within the gonads
germ cells
what does the gonads contain
ovaries and testes
What do germ cells do
they produce gametes
what are gametes
egg and sperm
How many pairs of chromosomes do GERM cells have
23 pairs
how many chromosomes do gametes have
only 1 pair of each chromosome
organized profile of all 46 chromosomes within an indivudal’s cells
karyotype
The __ is above the invisible straight line and the __ is below it
P arm and Q arm
all the non-sex chromosomes are called
autosomes
the pair of chromosomes that determine the gender of an individual
sex chromosomes
What sex chromosomes pair do you have if you’re a female
XX
What sex chromosomes pair do you have if you’re a male
XY
the pinched part of the chromosome, as pictured on the karyotype is called what
centromere
2 chromosomes that are paired together because they carry the same type of genes
Homologous Pairs
Each chromosome in a homologous pair of chromosomes is called a _________
homologue
What are the three possible destinies of a cell
- To remain alive and function w/o dividing
- To grow and divide
- to die
genetically programmed cell death
apoptosis
cell death due to disease, injury, or lack of blood flow
necrosis
the main energy-releasing pathway leading to ATP formation in eukaryotes
Aerobic Respiration
respiration that can release only small quantities of energy
anaerobic respiration
what is an example of anaerobic respiration
fermentation
What do both of the energy-releasing pathways begin with
glycolysis
the breakdown of 1 glucose into 2 pyruvate molecules
Glycolysis
glycolysis occurs in the _____ of the cells
cytoplasm
What is the breakdown of the Kreb Cycle
Acetyl CoA –> CO2 and H2O
Metabolic pathways should be thought of as
porus
Where is glycogen made and stored
the liver and muscle
the presence of glycogen in muscle cells allows ___ to be produced quickly during excercise
ATP
______ is broken down by various enzymes within cells.
Protein
Which lipid contributes to cell membrane flexibility and is a precursor of steroid hormones
Cholesterol
What does the synthesis of cholesterol start with
Acetyl CoA
what lipid is a form of long term energy storage in animals
Triglycerides
In comparison to carbohydrates, how much energy do triglycerides store
twice as much
what are triglycerides made of
1 glycerol and 3 fatty acids
What does DNA consist of
two anti-parallel strands of nucleotides twisted together in a double helix
a specific region along the DNA that codes for a specific protein
gene
What are the two steps in getting from DNA to proteins
transcription and translation
in transcription, sections of DNA are used as templates to produce ___ ________
RNA transcripts
where does transcription occur
the nucleus
In translation, the RNA transcripts are used as templates for _____ ______
protein assembly
where does translation occur
the cytoplasm by ribosomes
What three types of RNA are needed for protein synthesis
Messenger RNA, Ribosomal RNA, Transfer RNA
When does translation begin
when RNA polymerase binds to a promoter region
What does the RNA polymerase do after binding to a promoter region
moves along the entire length of the DNA gene, adding nucleotide bases to the growing mRNA molecule
Why can’t mRNA be used right when it’s formed
It needs to be modified before leaving the nucleus
introns =
interrupt
exons =
expressed
non-coding (introns) are ____
snipped out from the unfinished transcript of mRNA
actual coding regions are ____
spliced together on the unfinished transcript of mRNA
Shorter version of the mRNA process after it has been formed
snipped, capped, tailed
includes all the instructions of a gene that instructs a cell how to make a specific protein
Genetic Code
What is the mRNA transcript
a linear sequence of nucleotides
triplets on the mRNA are known as
codons
why are codons called codons
they code for a particular AA or for a stop signal during translation
How many codons code for an AA
61
how many of the codons serve as stop signals
3
“T shaped” molecule used to transport AAs
tRNA
how many tRNAs are there
61
Each tRNA contains an __________ that corresponds to the mRNA codon
anti-codon
each tRNA picks up its AA from a pool of _________ and carries it to the corresponding area on the _____ ___
free-floating AAs ; mRNA transcript
a minor exception to the rules of codon:anti-codon complimentary base-pairing
Wobble Effect
what does the Wobble Effect allow for
it allows for some latitude in the 3rd anticodon position.
rRNA are key components of _______
ribosomes (rRNA is ribosomal RNA)
Once the polypeptide chain is synthesized, the ribosomal subunits __________
disassociate
process by which tRNA/Ribosome/mRNA complex is formed
Initation
process by which the polypeptide chain lengthens
Elongation
the process by which the polypeptide chain is released from the RNA transcript.
Termination
what is the sequence of aggregation for initiation
initiator tRNA + small ribosomal subunit + mRNA + large ribosomal subunit
what defines the reading frame for elongation
the start codon
a caravan of tRNA delivers AAs in the approprate sequence vis __________ _______
codon-anticodon matching
What happens when a stop codon is reached
the polypeptide chain is released into the cytoplasm
all polypeptide chains begin with the AA methionine from the codon ___
AUG
