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Biology > Cells > Flashcards

Cells Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Magnification equation

A

Size of image / size of real object

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2
Q

What is resolution?

A

The minimum distance apart that two objects can be in order for them to appear as separate items

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3
Q

In cell fractionation the solution must be…

A

Cold- reduce enzyme activity
Same water potential as tissue- so organelles don’t burst or shrink because of osmosis
Buffered- so pH doesn’t fluctuate

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4
Q

Ultracentrifugation process

A

Tube of filtrate placed in centrifuge and spun on slow speeds
Heaviest organelles (nuclei) falls to the bottom forming a pellet
The fluid left (supernatant) is removed and then spun again at higher speeds
Next heaviest organelle falls (mitochondria)
Process continued

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5
Q

Compare light and electron microscopes

A

Light has a lower resolution as as it has a longer wavelength

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6
Q

What are limitations of the transmission electron microscope?

A

TEM must be in a vacuum
Only dead specimen can be observed
Specimen must be extremely thin

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7
Q

What is the nucleus?

A

Contains hereditary material and controls cell activity
Nuclear envelope- double membrane surrounding nucleus
Nucleoplasm- jelly-like material that makes up the the bulk of the nucleus

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8
Q

What is the mitochondria?

A

Site of aerobic respiration
Double membrane controls entry and exit
Cristae extensions of inner membrane
Matrix makes up remainder of mitochondria and makes enzymes

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9
Q

What are chloroplasts?

A

Where photosynthesis takes place.
Grana are stacks of thylakoids these contain the pigment chlorophyll and are where 1st stage of photosynthesis takes place. The stroma is where the 2nd stage of photosynthesis takes place

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10
Q

What is the rough endoplasmic reticulum?

A

Ribosomes I’m the outer surface which provides:
Large SA for synthesis of proteins and provides a pathway for transporting materials

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11
Q

What is the smooth endoplasmic reticulum?

A

Used for synthesis, store and transport of both lipids and carbohydrates

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12
Q

What is the fiction of the Golgi apparatus?

A

Form glycoproteins (carbohydrate+proteins)
Produces secretory enzymes
Secrete carbohydrates
Form lysosomes

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13
Q

What are lysosomes?

A

They hydrolyse material ingested by phagocytic cells and completely break down cells

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14
Q

What are ribosomes?

A

Site of protein synthesis
80s- found in eukaryotic cells
70s- found in prokaryotic cells

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15
Q

Compare prokaryotic and eukaryotic cells

A

P-no true nucleus E-distinct nucleus with nuclear envelope
P-DNA not associated with proteins E-DNA associated with histones(proteins)
P-no membrane-bound organelle E- membrane bound organelles
P- DNA can be circular E- DNA is linear
P-70s ribosomes E- 80s ribosomes

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16
Q

What is the structure of a virus?

A

Attachment proteins on the outside
Lipid envelope outside then matrix
RNA and reverse transcriptase in capsid

17
Q

What are the mitosis stages?

A

Prophase, metaphase, anaphase, telophase and cytokinesis

18
Q

What happened in prophase?

A

Chromosomes become visible
Spindle fibres develop from centrioles called spindle apparatus
Nucleolus disappears and nuclear envelope breaks down
Chromosomes drawn to equator by spindle fibres

19
Q

What happens in metaphase?

A

Chromosomes made of two chromatids
Chromatids joined by centromere
Chromosomes pulled along spindle apparatus on the equator

20
Q

What happens in anaphase?

A

Centromeres divide and spindle fibres pull chromatids apart
Chromatids move to opposite poles

21
Q

What happens in telophase?

A

Nuclear envelope and nucleolus reforms and spindle fibres disintegrate

22
Q

What molecules are in the cell membrane?

A

Phospholipids, proteins, cholesterol, glycolipids and glycoproteins

23
Q

What is the fluid mosaic model?

A

The cell membrane is fluid because individual phospholipids can move around
It is mosaic because the proteins are embedded

24
Q

What is diffusion?

A

The net movement of molecules from a region of high concentration to one of low concentration
Facilitated diffusion uses protein channels and carrier proteins

25
Q

What is osmosis?

A

The passage of water from a region of high water potential to one of low water potential through a selectively permeable membrane

26
Q

What happened to cells at different water potentials?

A

High water potential causes cells to swell and burst (turgid)
Equal water potential causes no change (incipient plasmolysis)
Low water potential causes cells to shrink (plasmolysed)

27
Q

What is active transport?

A

Movement of molecules from a region of low concentration to one of high concentration using ATP and carrier proteins

28
Q

The process of co-transport of glucose

A

Sodium ions actively transported out of epithelial cells by sodium-potassium pump
Higher conc of sodium in lumen instead of epithelial cells
Sodium diffuses into epithelial cells down conc gradient carrying glucose with it
Glucose pass into blood by facilitated diffusion

29
Q

What happens in phagocytosis?

A

The phagocyte is attracted to the pathogen and moves towards it on a conc gradient. The receptors on the membrane of the phagocyte attach to chemicals on the surface of the pathogen. Lysosomes within phagocyte migrate towards phagosome (engulfed bacteria). Lysosome releases lysozymes into phagosome to hydrolyse bacterium. Products from this are absorbed.

30
Q

What is the function of B lymphocytes?

A

Surface antigens of invading pathogen are taken up by B lymphocytes. It processes the antigens and puts them on its surface. Helper T cells attach to the antigens activating B cell. B cell divides by mitosis to clone plasma cell. This secretes specific antibodies to fit antigens on pathogens to destroy them. B cells can also develop into memory cells.

31
Q

What if the function of t lymphocytes?

A

Pathogens are taken in by phagocytes. The phagocyte puts antigens from pathogen on its surface. Receptors on specific helper T cells fit onto the antigens. This activates the T cells to divide by mitosis and form clones which can: develop into memory cells, stimulate phagocytes, stimulate B cells to divide and activate cytotoxic T cells

32
Q

What are monoclonal antibodies?

A

An antibody that can be isolated and cloned

33
Q

How can monoclonal antibodies target medication to specific cells?

A

Monoclonal antibodies are produced that are specific to antigens on cancer cells. They are given to a patient and attach themselves to receptors on cancer cells. They attach to the surface and block chemical signals that stimulate their uncontrolled growth.

34
Q

What are the different types of immunity?

A

Passive- antibodies that are in individuals from an outside source
Active- stimulating the production of antibodies. There are two types: natural active which is from an individual being infected by disease
Artificial active is from vaccinations

35
Q

How does HIV replicate?

A

HIV enters bloodstream. A protein on HIV readily binds to CD4. Protein capsid fuses with cell membrane. The RNA and enzyme from HIV enter helper T cell. HIV reverse transcriptase converts virus RNA to DNA. This DNA moves into helper T cells nucleus and creates mRNA. mRNA creates HIV using protein synthesis and BIV breaks away from helper T cell

Biology (7 decks)

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