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AQA A level biology <33 > Topic 2- Cells > Flashcards

Topic 2- Cells Flashcards

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1
Q

What is the nuclear envelope?

A

A double membrane surrounding the nucleus , which controls entry and exit of materials.

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2
Q

What is the function of the mitochondria?

A

The site of aerobic respiration and production of ATP

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3
Q

What are cristae?

A

Folds in the inner membrane of the mitochondria or mitochondrion .
They are the site of oxidative phosphorylation .

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4
Q

What is the rough endoplasmic reticulum?

A

System of membranes that is continuous with the nucleus, with ribosomes on the outer surface. Site of transportation and synthesis of proteins & glycoproteins

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5
Q

How does the structure of the rough endoplasmic reticulum help enable synthesis of proteins?

A

the rough endoplasmic reticulum has ribosomes and a large surface area

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6
Q

What is the smooth endoplasmic reticulum?

A

systems of membranes with no ribosomes on the outer surface

site of synthesis, storage and transportation of lipids and carbohydrates

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7
Q

What are the 4 functions of the Golgi apparatus?

A

1) Produces secretory enzymes and carbohydrates.
2) Stores and modifies proteins and triglycerides.
3) Forms vesicles for transporting proteins/triglycerides.
4) Forms lysosomes.

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8
Q

What is a lysosome?

A

A lysosome is a membrane-bound organelle that releases hydrolytic enzymes.

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9
Q

What is the structure of ATP?

A

a pentose sugar(ribose)
a nitrogenous base(adenine)
three organic phosphate groups

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10
Q

What is the function of ATP?

A

An immediate source of energy for biochemical processes and synthesis of biological molecules.

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11
Q

How does the structure of ATP make it a good source of immediate energy?

A

The bonds between the phosphate groups have a low activation energy . This means they can be easily broken . Breaking the bonds releases energy .

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12
Q

Define active transport

A

Active transport is the movement of molecules from a region of low concentration
to high concentration, using carrier proteins and energy from the synthesis of ATP.

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13
Q

What are grana?

A

Stacks of thylakoids found in the chloroplast

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14
Q

What are thylakoids?

A

Flattened sacs in the chloroplast, containing chlorophyll .

Site of the light - dependent reaction for photosynthesis

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15
Q

What is the stroma?

A

The stroma is the matrix of the chloroplast in a plant cell.

Site of the light - independent reaction for photosynthesis .

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16
Q

What is the function of the plant cell wall?

A

Provides rigidity to the cell and stops the cell from bursting by exerting inward pressure to prevent osmosis .

This enables turgidity which makes parts of the plant semi-rigid.

17
Q

What are plant cell walls mainly composed of?

A

the polymer cellulose

18
Q

What is a vacuole?

A

A fluid-filled sac with a single membrane.

19
Q

What is the function of the vacuole in a plant cell?

A

It supports the plant by making cells turgid .

Stores sugars and amino acids which can act as a temporary food storage.

In petal cells, it can store pigments to attract pollinating insects.

20
Q

State three purposes of mitosis

A

Mitosis is needed for growth, repair and asexual reproduction

21
Q

State two purposes of meiosis.

A

Meiosis is needed for production of haploid cells for sexual reproduction.
It helps ensure genetic variation.

22
Q

Define mitosis in terms of the daughter cells produced.

A

The cell divides once to produce two daughter cells.

Each daughter cell has an identical copy of the DNA produced by the parent cell during replication.

23
Q

Define meiosis in terms of the daughter cells produced.

A

The cell divides twice to produce four daughter cells.

Each daughter cell is genetically different

24
Q

What is the function of the phospholipid bilayer?

A

Allows diffusion of lipid soluble substances.

Prevents movement of water soluble substances

25
Q

What are two functions of cholesterol embedded in the cell membrane?

A

Reduce fluidity and permeability of the cell membrane.

Increase rigidity of the cell membrane.

26
Q

What is a glycoprotein?

A

A protein attached to a carbohydrate chain on the cell-surface membrane.

27
Q

What are the two functions of a glycoprotein?

A

Acts as a recognition site for hormones, neurotransmitters and other cells.
Helps cells attach together to form tissues.

28
Q

Define simple diffusion

A

A passive method of transport across the cell membrane via the phospholipid bilayer .

29
Q

Define facilitated diffusion

A

A passive method of transport across membranes involving carrier proteins and channel proteins

30
Q

What type of transport are protein channels involved in?

A

Involved in facilitated diffusion across the cell membrane

31
Q

What type(s) of transport are carrier proteins involved in?

A

Involved in facilitated diffusion and active transport across the cell membrane

32
Q

What is the term used to define the response of T cells to a foreign antigen?

A

cell mediated immunity

33
Q

Define humoral immunity

A

Humoral immunity is the response of B lymphocytes to a foreign antigen, clonal selection and the release of monoclonal antibodies

34
Q

How does the secondary immune response differ from the primary immune response?

A

In the secondary immune response, plasma cells and antibodies are produced at higher speed and concentration as a result of memory cells produced during the primary immune response

35
Q

What is an antibody?

A

A protein produced by B lymphocytes in response to the presence of a specific antigen

36
Q

What are monoclonal antibodies?

A

Antibodies with the same tertiary structure, produced from cloned B-lymphocytes

37
Q

Describe active immunity

A

Resistance that arises as a result of exposure to an antigen , which causing B lymphocytes to produce antibodies

38
Q

Define passive immunity

A

Resistance that arises when antibodies introduced into the body (either from injection or breastfeeding) bind to and destroy specific toxins/venoms/antigens.

39
Q

How does herd immunity work?

A

When more people are immune, fewer people carry the pathogen, so unvaccinated people are less likely to make contact with infected people.

AQA A level biology <33 (12 decks)

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