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Forensics Biology Flashcards

1
Q

What is the structure and function of the plasma membrane?

A

It is composed of a phospholipid bilayer with proteins embedded in the layer. Its is selectively permable and regulates the transport of materials into and out of the cell. It separates cell content from the outside content.

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2
Q

What is the structure and function of the cytoplasm?

A

It is a thick, gelatinous, semi-transparent fluid. It maintains the cell shape and stores the chemicals needed for metabolic reactions.

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3
Q

What is the structure and function of the nucleus?

A

It is the largest organelle and is surrounded by a nuclear envelope. It has nuclear pores which allow movement of molecules through it. It controls/regulates cellular activity and houses genetic material- chromatin, DNA and proteins.

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4
Q

What is the structure and function of the nucleolus?

A

Dense spherical structure in the middle of the nucleus. It makes rna and ribosomes.

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5
Q

What is the structure and function of the rough endoplasmic reticulum?

A

It is a network of embrace bound flattened sacs called cisternae and is studded. With ribosomes. Proteins synthesis takes place on the ribosomes and newly synthesised proteins are. Transported to the Golgi apparatus.

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6
Q

What is the structure and function of the smooth endoplasmic reticulum?

A

It is a network of membrane bound flattened sacs called cisternae and they are not studded with ribosomes. They are responsible for the transportation of lipids and carbohydrates.

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7
Q

What is the structure and function of the Golgi apparatus?

A

A stack of membrane bound flattened sacs. Newly made proteins are received here from the rough endoplasmic reticulum. They are modified, packaged into vesicles and transported when they are needed.

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8
Q

What is the structure and function of vesicles?

A

small spherical membrane bound sacs with fluid inside the cell. Secretory vesicles transport proteins that are to be released from he cell to the cell surface membrane.

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9
Q

What is the structure and function of lysosomes?

A

Small spherical membrane bound sacs that contain hydrologic enzymes. They break down waste material. Which includes old organelles.

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10
Q

What is the structure and and function of 80s ribosomes?

A

Tiny organelles attached to the rough endoplasmic reticulum or free floating. They consist of two sub units and are not surrounded by a membrane. This is where protein synthesis occurs.

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11
Q

What is the structure and function of mitochondria?

A

It has two membranes. The inner is highly folded to form cristae and the central part is called the matrix. They are the sight of aerobic respiration and produce energy in the form of ATP.

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12
Q

What is the structure and function of centrioles?

A

Small tubes of protein fibres. They form spindle fibres during cell division.

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13
Q

What is the structure and function of the cell wall?

A

Made of cellulose which forms a sieve like network. It protects and support each cell and the whole plant.

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14
Q

What is the structure and function of chloroplasts?

A

It has a double membrane and is filled with the fluid stoma. The inner membrane is a continuous network of flattened sacs called thylakoids. A stack of thylakoids is a granular. These contain chlorophyll which absorbs light energy for photosynthesis.

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15
Q

What is the structure and function of a vacuole?

A

A membrane bound sac in the cytoplasm which contains cell sap. It maintains turgor t ensure a rigid framework in the cell.

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16
Q

What is the structure and function of the tonoplast?

A

Partially permeable membrane of the vacuole. Selectively permeable to allow small molecules to pass through.

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17
Q

What is the structure and function of an amyloplast?

A

A double membrane bound sac containing starch granules. It is responsible for the synthesis and storage of starch granules.

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18
Q

What is the structure and function of the plasmodesmata?

A

Microscopic channels which cross te cell walls of plant cells. They enable transport and communication between individual plant cells.

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19
Q

What is the structure and function of pits?

A

Pros in the cell wall of the xylem. They allow water to enter and leave the xylem vessels.

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20
Q

What is the function of an animal cell?

A
  1. Proteins are synthesised at ribosomes on the rough endoplasmic reticulum
  2. It is transported through cisternae of the rer and put into transport vesicles.
  3. Golgi modifies proteins and the puts them into secretory vesicles.
  4. Secretory vesicles fuse with the cell membrane and release proteins by exocytosis.
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21
Q

What is the structure and function of the cell wall? (Bacteria)

A

Prokaryotic cells are surrounded by a cell wall made of peptidoglycan. It protects and supports the cell.

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22
Q

What is the structure and function of the capsule?

A

Slippery layer outside of the cell wall. It is made of hipopolysacchrides. It protects the cell nd prevents drying out.

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23
Q

What is the structure and function of the nucleoid?

A

It is an irregularly shaped region that holds nuclear material without a nuclear membrane and where genetic material is localised. The DNA forms one circular chromosome. It is free floating in the cytoplasm where genetic information is found and controls cellular activity.

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24
Q

What is the structure and function of the plasmid?

A

Small loops of DNA. Plasmids carry genes that may benefit the survival of an organism.they can also transfer genetic information.

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25
What is the function of prokaryotic cells?
1. DNA gene unwinds. 2. RNA nucleotides line up next to DNA and make mRNA transcriptions. 3. MRNA is converted to toxic protein at a ribosome.(translation) 2nd stage of protein synthesis. 4. Toxic protein sent to the cell membrane and is rebased.
26
What is the structure of something that is gram positive?
Thick layers of peptidoglycan (40). One lipopolysaccharide inner membrane.
27
What is the result is it is gram positive?
1.Iodine gets stuck in thick and exposed peptioglycan. 2. Appears purple in colour.
28
What is the response to penicillin if it is gram positive?
1. Susceptible to penicillin. 2. Peptidoglycan wall is not protected by a membrane. 3. Penicillin inhibit enzymes and disrupts cell wall synthesis. 4. Cell grows abnormally with holes in the wall and it splits/bursts. 5. Cells die.
29
Example of gram positive bacteria.
Staphylococcus’s epidermis
30
What is the structure of a prokaryote that is gram negative?
Thin layers of peptioglycan. (1-2 layers) two lipopolysaccharide membranes.
31
What happens if the results is gram negative?
1. Iodine can’t stick yo peptidoglycan as it is protected by an outer membrane. 2. Outer membrane dehydrated by ethanol (de colourised) 3.peptidoglycan exposed and red safranin. Counterstain binds so it appears red/pink in colour.
32
What is the response to penicillin?
1. Not susceptible to penicillin. 2. Peptidoglycan layer is protected by two lipopolysacchride membranes. 3. Penicillin can’t get through the outer membrane. 4. Cell wall synthesis is not disrupted. 5. Cell does not burst d die.
33
Give an example of gram negative bacteria
E.coli
34
How do you carry out a gram stain?
1. Bacteria is placed onto a glass slide. 2. Bacteria is submerged into crystal violet (primary dye) 3. Washed and the iodine is added. (Mordant) 4. Dehydrate using ethanol.(de colourise) 5. Submerge into red safranin. (Counterstain) 6. Rinse, dry and then view under a microscope.
35
What are the differences between prokaryotic and eukaryotic cells?
Prokaryotic- DNA is contained in the nucleoid, they have no membrane bound organelles, they are much smaller, 70s ribosomes and peptidoglycan cell wall. Eukaryotic- DNA is contained in the nucleus, they do have membrane bound organelles, they are much larger, 80s ribosomes and a cellulose cell wall in plants.
36
What is the definition of magnification?
How much larger the image appears to be compared to its actual size.
37
What is the definition of resolving power? (Resolution)
How close together objects cn be and still be seen as separate. This depends on the wavelength of the radiation used.(how much detail can be seen.
38
What are the advantages of light microscopes?
- can observe live specimen -can observe colour -preparation is the slide is quick -stains are non toxic -portable -no specialist training needed
39
What are the disadvantages of a light microscope?
-light has a long wavelength -low resolving power -high magnification
40
What are the advantages of transmission electron microscopes? (TEM)
-electrons have a short wavelength -high resolving power -high magnification -can observe small organelles like ribosomes
41
What are the disadvantages of transmission electron microscopes?
-cannot observe live specimen -black and white images -slide preparation is long and complex -stains are toxic -not portable -requires specialist training
42
What are the advantages of scanning electron microscopes?
-electrons have a short wavelength -very high resolving power -high magnification -produces a 3D image so 3D structure can be observed
43
What are the disadvantages of a scanning electron microscope?
-cannot observe live specimen -cannot see internal structure -black and white image produced -long and complex slide preparation -not portable -specialist training is required
44
What equation links image size, actual size and magnification?
Magnification=image size/actual size
45
What is a stem cell?
They are cells that are undifferentiated meaning they have no particular structure or function. They then differentiate to become specialised with specialised structures and functions. All stem cells are able to divide and differentiate.
46
What are the key features of adult stem cells?
They can be unipotent or multipotent. They can only differentiate into a limited number of cells. (Multi potent) Marrow cells in bones can only become blood cells. (Unipotent)
47
What are the key features of embryonic stem cells?
They are pluripotent. They differentiate into any cell type in the body. They are found in early embryos.
48
What are they key features of induced pluripotent cells?
They are pluripotent. They are regular non potent cells that have been reprogrammed in a lab to switch genes to behave like embryonic stem cells.
49
Explain the features and functions of a palisade mesophyll cell.
- cylindrical shape = allows maximum absorption of light. - located close to the epidermis at the top of the leaf = allows maximum exposure to light - cells close together= large surface area for absorbing light - narrow gaps between cells = allows air to circulate for gas exchange - thin cell wall = rapid diffusion of gases (o2 and co2) - transparent cell wall = east for light to penetrate and reach chloroplasts - large vacuole = helps to keep structure under isotonic pressure - many chloroplast = for plentiful absorption of light. - cytoplasm can move chloroplasts around = increases light absorption in dim light and protects them in bright light
50
Explain the features and functions of root hair cells
- extended projection = large surface area for more absorption of water and mineral ions - many cell membrane protein channels = rapid absorption of water by osmosis - many cell membrane protein carriers = rapid absorption of mineral ions by active transport. - thin cell wall = rapid diffusion rate. - many mitochondria = to provide lots of ATP For active transport - large vacuole filled with cell sap = makes the water potential low which speeds up osmosis.
51
Similarities between a root hair cell and palisade mesophyll cell
Both have a nucleus, nucleolus, cellulose cell wall, plasma membrane, cytoplasm, 80S ribosomes, RER, SER, Golgi apparatus, vesicles, lysosomes, mitochondria and a permanent vacuole.
52
Differences between root hair cell and palisade mesophyll cell
Palisade mesophyll cells have : -cylindrical shape for maximum absorption of light - locates at the top of the epidermis for maximum exposure to light - many chloroplasts to absorb light for photosynthesis, Root hair cells have: -hair like projections for a large surface area. -large vacuole with sap lowers the water potential for osmosis. -no chloroplasts as they do not need sunlight.
53
What are the features and functions of a sperm cell?
- haploid nucleus with 23 chromosomes = contains father’s DNA (half the normal amount so it can merge with the mother’s DNA) -head containing an acrosome = contains hydrolytic enzymes that allow sperm to digest the zona pellucida. -many mitochondria = can produce a lot of ATP from respiration which provides energy for the flagellum to propel the cell. -flagellum = allows for motility (self propelled movement)
54
What are the features and functions of an ovum cell?
-haploid nucleus with 23 chromosomes = contains the mother’s DNA (half the normal amount so it an merge with the father’s DNA) -large mount of cytoplasm and organelles = organelles for protein synthesis and cytoplasm for nutrients and space for an embryo to grow. -many mitochondria = produces ATP energy which is needed for DNA replicated and cell growth of embryo. -zona pellucida = acts as a barrier to sperm entry. Only on sperm cell can enter, -corona radiata = provides support and supplies proteins to a developing embryo.
55
What happens during the fertilisation process?
-sperm enters the vagina after ejaculation -sperm uses energy from ATP to move towards the ovum. -sperm meets the ovum and pushes through the corona radiata cells. -sperm acrosomes releases hydrolytic enzymes to soften the zona pellucida -sperm pushes through the softened pellucida. -sperm nucleus enters the ovum. -cortisol reaction causes enzymes to make the zone pellucida harden and destroys sperm binding sites so no more sperm can enter.
56
What are the features of all white blood cells?
-all made in the bone marrow from stem cells -all have a nucleus, mitochondria, RER and 80S ribosomes. -all involved in defence against pathogens -all transported in blood plasma -all migrate to a fluid in body tissues when needed.
57
Lymphocyte- T cells
- Involved in specific/adaptive immune responses - antigen receptors on surface -smaller then neutrophils -have a large nucleus -T helper cells send signals to B cells to activate them - T cytotoxic cells destroy infected and cancerous cells. - T memory cells provide immunological memory.
58
Lymphocyte- B cells
-involved in specific/adaptive immune responses -antigen receptors on their surface Smaller then a neutrophils - have a large nucleus - B cells proliferate after receiving signals from T helper cells. - B cells proliferate into plasma cells which provide immunologic memory.
59
Neutrophils
- most common white blood cell - involved in non-specific immune responses (no antigen receptors) -phagocytes= engulfs pathogen -many lysosomes containing hydrolytic enzymes to digest pathogens. -multilobed flexible nucleus asking cells flexible enough to squeeze through capillary walls to migrate to an area of infection. -do not form memory cells -release chemicals that cause inflammation.
60
What happens during phagocytosis?
1. The neutrophils approaches the pathogen 2. The neutrophil engulfs the pathogen. 3. The pathogen gets trapped in a vesicle called a phagosome. 4. Lysosomes fuse with the phagosome and release hydrolytic enzymes which break down and digest the pathogen.
61
Red blood cells
- no nucleus, mitochondria, ribosomes, RER (no organelles) so more surface area to bind to oxygen. -lots of haemoglobin to bind to oxygen (each haemoglobin molecule can bind to 4 oxygens) -small size and bi-concave shape makes them flexible to squeeze through capillaries. -bi-concave shape increases the surface area to volume ration. -haemoglobin in the cytoplasm is close to cell membrane meaning a short diffusion path for oxygen.
62
Roles in responses: immunity
1. Pathogens get detected by T helper cells and send signal to B cells. 2. B cells become plasma cells to produce antibodies. 3. Antibodies bind to pathogen and call phagocytes to engulf it 4.memory T cells and B cells remain in the blood to provide immunity.
63
Roles in responses :allergic reactions
1. T cells identify the allergen as foreign and releases chemicals in response. 2. These chemicals travel through blood and instruct B cells to produce immunoglobin antibodies. 3.some of the IGE antibodies attach to mast cells (white blood cells scattered throughout the skin and respiratory tract) the mast cells help mediate the inflammatory response. 4. When the same allergen is encountered again, it binds to the IGE antibody attached to the mast cell. 5. This. Activates the mast cell and releases chemical such as histamine causing many of the symptoms associated with allergies. E.g. inflammation, itching/watery eyes and increased mucus production. (Runny nose)
64
Roles in response: organ transplant rejection
1. A healthy immune system can distinguish between the bodys own antigens(self) and foreign(non-self) 2. Transplanted organs are made entirely of cells with non-self antigens 3. T cells will destroy these foreign non self cells by producing antibodies destroying the organ cell by cell. 4. To minimise this immune response, donors and recipients should have matching antigens on their blood and tissues. 5. Only donated tissue from an identical twin will be fully accepted by a recipients body. 6. To prevent rejection, transplant patients are treated with immunosuppressive drugs. These block the immune response by reducing the production of antibodies and T cells.

Psychology And Forensics (6 decks)

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