cell biology Flashcards
(51 cards)
What are the main differences between prokaryotic and eukaryotic cells?
Prokaryotic cells are smaller + lack a nucleus ( store DNA in a single circular loop )
Eukaryotic cells are larger + have DNA enclosed ( within a nucleus )
Name 3 structures found in plant cells but not in animal cells.
Cell wall
Chloroplasts
Large permanent vacuole.
What is the function of the ribosomes?
The site of protein synthesis where amino acids are joined to form proteins
What is the role of the cell membrane?
It controls the movement of substances in and out of the cell and helps maintain internal conditions
Why do muscle and sperm cells contain many mitochondria?
To provide large amounts of ATP energy through aerobic respiration needed for movement
What is the function of the vacuole in plant cells?
It maintains turgor pressure and stores cell sap (water, ions, and sugars)
Which type of microscope gives higher resolution: light or electron?
Electron microscopes
What is magnification?
The process of enlarging the appearance of an object compared to its actual size
What is the formula for magnification?
Magnification = Image size ÷ Actual size.
A cell image is 2 mm long, and the actual cell is 10 µm. What is the magnification?
2 mm = 2000 µm; Magnification = 2000 ÷ 10 = 200×.
Why do cells become specialised?
To carry out specific functions more efficiently by developing specialised structures
Name a specialised animal cell and explain how it’s adapted.
A nerve cell has a long axon to transmit impulses and many mitochondria to release energy
How is a root hair cell adapted for its function?
It has a large surface area for water absorption and thin walls for quick osmosis
What is the main function of xylem cells?
To transport water and mineral ions from the roots to the leaves
Why don’t red blood cells have a nucleus?
To maximise space for haemoglobin, allowing more oxygen to be carried
What is mitosis used for?
Growth, repair, replacement of cells, and asexual reproduction
Describe the stages of the cell cycle.
- Growth phase (organelles and DNA replicate)
- Mitosis (nucleus divides)
- Cytokinesis (cytoplasm divides)
During which phase is DNA replicated?
During the interphase (growth phase) before mitosis begins
What is the purpose of mitosis?
To produce genetically identical diploid cells for growth and repair.
What are stem cells?
Undifferentiated cells that can divide and differentiate into specialised cells
What are the differences between embryonic and adult stem cells?
Embryonic stem cells can become any cell type (pluripotent); adult stem cells are limited to certain types (multipotent)
Why is stem cell therapy controversial?
It involves the use of human embryos, raising ethical concerns about life and consent
How can stem cells be used in medicine?
To treat conditions like paralysis, diabetes, and leukemia by regenerating damaged tissues
What is therapeutic cloning?
Creating an embryo with the same DNA as a patient so stem cells can be used without immune rejection
