Animal Cells Flashcards
What is differentiation?
Process by which stem cells become specialised into different types of cell.
What are epithelial cells?
Cells that constitute lining tissue.
What is an erythrocyte?
A red blood cell.
What is a neutrophil?
A type of red blood cell that is phagocytic- can invest microbes and small particles.
Explain what a stem cell is.
An unspecialised cell able to express all of its genes and divide by mitosis.
Single called organisms are small and therefore have a large what?
Surface area to volume ratio.
Give two reasons for the need of a large SA:V ratio.
It means lots of oxygen can quickly and efficiently diffuse into the cell and waste products can diffuse out of the membrane efficiently.
Why do larger organisms need specialised cells?
Most of their cells aren’t in contact directly with the exterior environment, therefore they need specialised cells to carry out a particular function.
How does a multicellular embryonic organism start life?
As a single undifferentiated cell called a zygote.
Explain how a zygote forms.
The suite is made when an ovum is fertilised by a sperm and the two haploid nucleus’ fuse (= diploid nucleus). The zygote is unspecialised and all of the genes in its genome an be expressed and t an divide by mitosis.
What is a genome?
The genetic material within an individual
What can happen to genes during differentiation?
Some can be swiched off and some expressed more.
List three reasons as to why certain genes may be switched off or expressed more during differentiation.
The proportions of the different organelles differ from those of other cells, the shape of the cell changes and some of the contents of the cell changes.
From where do erythrocytes and neutrophils derive?
Stem cells within the bone marrow
List the five types of specialised animal cells.
Neutrophil Erythrocyte Spermatozoa Ciliated epithelia Squamous epithelia
What is the function of erythrocytes?
They carry oxygen from the lungs to respiring cells.
List all of the adaptations of erythrocytes to make them more efficient for their function of carrying oxygen from lungs to respiring cells.
They are small (7.5 micrometers) and biconcave shape= large SA:V= quicker O2 did fiction into cell/ well developed cytoskeleton- v flexible- can change shape and twist and turn to fit through narrow capillaries/ in differentiation, the ER, mitochondria and nucleus are lost to make more space for more haemoglobin.
What is the function of neutrophils?
To ingest invading pathogens by phagocytosis.
Explain the adaptations of neutrophils for its function.
x2 size of erythrocytes, have receptors on the plasma membrane to let opsonin bind, lobed nucleus- lets cell squeeze through narrow gaps, many lysosomes with lysin, lots of ribosomes to synthesise the enzymes needed, well developed cytoskeleton- flexible- phagocytosis.
What is a spermatozoa?
They are sex cells
What are the three adaptations of the spermatozoa for its function?
small long+ thin- easily move// mitochondria provide ATP so tail moves// enzymes in its head that digest the outer layer of the ovum so the sperm can enter its nucleus.
Explain the function of squamous epithelial cells.
It is lining tissue that is a mediator for the filtration and diffusion of a cell
Explain the function of the ciliated epithelial cells.
To move particles or fluid over the epithelial surface, in structures like the trachea or nasal system.
Explain some adaptations of squamous epithelial cells for its function.
Small, thin and flattened cells that allow small molecules to diffuse quickly and easily across the surface. They have transmembrane protein channels that allow ions to diffuse through the membrane.
Explain some adaptations of ciliated epithelia cells for their function.
That have a large SA:V ratio and a thin membrane to allow short diffusion path if it’s needed (eg in the small intestine) and the long protrusions move things (eg. The mucus bang in the trachea).
