Cell biology Flashcards
How are sperm cells specialised?
The function of the sperm is to get the male DNA to the female DNA. It has a long tail and a streamlined head to help it swim to the egg. It has a lot of mitochondria to provide the energy needed.. Carries enzymes in the head to digest through the egg cell membrane.
How are nerve cells specialised?
Nerve cells are specialised for rapid signalling. The function of nerve cells is to carry electrical signals from one part of the body to another. These cells are long, to cover more distance and have branched connections at their ends to connect to other nerve cells and form a network throughout the body.
How are muscle cells specialised?
Muscles are specialised for contraction. The function of a muscle cell is to contract quickly. The cells are long so they have space to contract, and contain lots of mitochondria to transfer the energy needed for contraction.
How are root hair cells specialised for their function?
Root hair cells are specialised for absorbing water and minerals. They grow into long “hairs” that stick out into the soil. This gives the plant a big surface area for absorbing water and mineral ions from the soil.
How are xylem and phloem cells specialised for their unction?
They are specialised for transorting substances. They form phloem and xylem tubes, these transport substances such as food and water around plants. To form the tubes, the cells are long and joined end to end. Xylem cells are hollow in the centre and phloem cells have very few subcellular structures, so that substances can flow around them.
What is cell differentiation?
This is the process by which a cell changes to become specialised for its job. As cells change, they develop different subcellular structures and turn into different types of cells.
When does differentiation occur for plant and animal cells?
Most types of animal cell differentiate at an early stage. This ability to differentiate is then lost after they become specialised.
Many types of plant cells retain the ability to differentiate throughoutlife.
Mature animals cell differentiation?
In mature animals, cell division is mainly restricted to repair and
replacement.
Explain what specialisation is.
As a cell differentiates it acquires different sub-cellular structures to enable it to carry out a certain function. It has become a
specialised cell.
Describe the cell cycle.
During the cell cycle the genetic material is doubled and then divided into two identical cells.
Before a cell can divide it needs to grow and increase the number of
sub-cellular structures such as ribosomes and mitochondria. The DNAreplicates to form two copies of each chromosome. In mitosis one set of chromosomes is pulled to each end of the cell and the nucleus divides. Finally the cytoplasm and cell membranes divide to form two identical cells.
What does active transport allow plants to do?
Active transport allows mineral ions to be absorbed into plant root hairs from very dilute solutions in the soil. Plants require ions for healthy growth.
What does active transport allow animals to do?
It allows sugar molecules to be absorbed from lower concentrations in the gut into the blood which has a higher sugar concentration. Sugar molecules are used for cell respiration.
What is active transport
The movement of substances from an area of low concentration to an area of high concentration against the concentration gradient.
What are substances diffused in the body?
Some of the substances transported in and out of cells by diffusion are oxygen and carbon dioxide in gas exchange, and of the waste product urea from cells into the blood plasma for excretion in the kidney.
