Cell Organelles
What organelle is the site for cellular respiration?
mitochondria
What type of transport moves substances from high to low concentration without energy?
Passive transport
What is the purpose of mitosis in the human body?
Growth, repair, and maintenance of tissues
What is the purpose of meiosis?
To produce gametes with half the number of chromosomes
How many chromosomes are found in a normal human karyotype?
46
Which organelle packages and modifies proteins for transport?
Golgi apparatus
In what type of solution does a cell neither shrink nor swell?
Isotonic
During which phase of the cell cycle does DNA replicate?
S phase of interphase
To produce gametes with half the number of chromosomes
Haploid
What can a karyotype reveal?
The number, size, and shape of chromosomes; abnormalities like extra or missing chromosomes
What is the function of the rough endoplasmic reticulum?
Synthesizes and transports proteins due to ribosomes on its surface
A cell must move sodium ions out even though there is already a higher concentration outside. What process is used?
Active transport (sodium-potassium pump)
In which phase of mitosis do sister chromatids separate?
Anaphase
How does crossing over increase genetic variation?
It exchanges genetic material between homologous chromosomes, creating new allele combinations
A karyotype shows 47 chromosomes with an extra chromosome 21. What condition is this?
Down syndrome
If a cell’s lysosomes were damaged, what would likely happen to the cell?
It would accumulate waste and damaged organelles, eventually harming or killing the cell
Why would a red blood cell placed in a hypertonic solution shrink? (solute concentration)
Water leaves the cell because the solution has a higher solute concentration than the cytoplasm.
A student observes cells under a microscope and sees chromosomes aligned along the equator. What stage is this?
Metaphase
Why do siblings (except identical twins) not look exactly alike?
Independent assortment and crossing over create unique combinations of genes in gametes
A doctor uses amniocentesis for genetic testing. What is obtained and analyzed?
Fetal cells from amniotic fluid to examine chromosomes for abnormalities
A neuron has many mitochondria and extensive rough ER. What does this indicate about the neuron’s activity?
It has high energy needs and produces many proteins for neurotransmission
A hospital accidentally gives a patient an IV of pure water instead of saline. What happens to the patient’s red blood cells, and why?
They swell and burst due to osmosis — the cells are in a hypotonic solution
A person’s skin heals quickly after a cut. Explain how the cell cycle contributes to this process.
Cells rapidly divide through mitosis to replace damaged tissue
A scientist finds a gamete with an extra chromosome. What error likely occurred during meiosis, and what could be the result?
Nondisjunction; could cause disorders like trisomy 21 (Down syndrome)
A male patient’s karyotype shows XXY. Predict the syndrome and likely symptoms.
Klinefelter syndrome; typically tall stature, infertility, and some female characteristics