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Biology unit 3 > Cell structure and microscopy > Flashcards

Cell structure and microscopy Flashcards

1
Q

What are cells?

A

The basic unit of all living organisms. They contain genetic information in a nucleus or nuclei, a cytoplasm and ribosomes

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2
Q

What is a tissue?

A

A group of similar cells which work together to perform a specific function

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3
Q

What is an organ?

A

A group of tissues which work together to perform a specific function

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4
Q

What is an organ system?

A

A group of organs that work together to perform a particular function

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5
Q

State 8 organelles found in animal cells

A

Nucleus, mitochondria, ribosomes, rough endoplasmic reticulum, smooth endoplasmic reticulum, centrioles, golgi body, lysosomes

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6
Q

What is the function of the nucleus?

A

To store and transmit genetic material

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7
Q

What is the function of nuclear pores?

A

To allow substances to enter and exit the nucleus

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8
Q

What is chromatin?

A

DNA wrapped around histone proteins

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9
Q

Describe the structure and function of the rough endoplasmic reticulum

A

Studded with ribosomes, made up of membranes folded into cisternas. It synthesizes proteins destined to be secreted

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10
Q

Describe the structure and function of mitochondria

A

Double membrane folded into chrisae. There’s fluid with matrix inside. It contains its own DNA (mDNA). It’s a site of ATP production through aerobic respiration

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11
Q

What is the function of lysosomes? What do they contain?

A

They break down substances so they can be used. They contain hydrolytic enzymes that break down waste

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12
Q

What is the function of vesicles?

A

To transport substances within cells

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13
Q

What is the structure and function of ribosomes?

A

Two units made of protein and rRNA. They synthesize proteins

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14
Q

Describe the structure of the Golgi body

A

It’s a membrane-bound organelle folded into cisternae

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15
Q

What is the function of the Golgi body?

A

It modifies and processes lipids and proteins and packages them into vesicles.

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16
Q

Describe the structure and function of lysosomes

A

Membrane-bound vesicles that contain hydrolytic enzymes that break down waste and toxins.

17
Q

Describe the structure of centrioles

A

A cylindrical bunch of protein called tubules. They’re often found in pairs which make up a structure called centrosome.

18
Q

Name the components of a chloroplast (7)

A

Inner membrane, outer membrane, grana, stroma, ribosome, thylakoid, intergranal lamellae

19
Q

What is an intracellular enzyme?

A

An enzyme that acts within cells. Ex catalase

20
Q

What is an extracellular enzyme?

A

An enzyme that is secreted by cells and functions outside of cells. Ex amylase

21
Q

Describe the steps involved in the production of an extracellular enzyme

A
  1. DNA transcribed to produce mRNA in the nucleus
  2. mRNA exits the nucleus and travels to a ribosome on the rER
  3. Enzyme synthesized by the ribosomes in translation
  4. Enzyme is packaged into a vesicle and sent to the Golgi apparatus where it’s repackaged and modified
  5. The enzyme leaves the Golgi apparatus enclosed in a vesicle and undergoes exocytosis to exit the cell
22
Q

What is the function of the flagellum?

A

To move the cell

23
Q

What is the function of the pili?

A

They allow the bacteria to adhere to other cells or surfaces

24
Q

What is the function of plasmid DNA?

A

To provide beneficial genes which aid in the survival of the prokaryote.

25
Q

What is the function of the bacterial capsule?

A

It protects the cell from dry environments and it acts as a virulence factor which helps resist phagocytosis

26
Q

What is the magnification of a microscope the measurement of?

A

How many times bigger the image appears compared to the original object

27
Q

What is the formula for calculating magnification?

A

image size = actual size x magnification
actual size = image size / magnification
magnification = image size / actual size

28
Q

What is the purpose of staining specimens?

A

To visually distinguish different parts of a specimen and to increase contrast. Lots of cellular components are transparent

29
Q

What is differential staining?

A

A form of staining used to distinguish between different parts of the specimen using different stains

30
Q

How do light microscopes work?

A

They use lenses to magnify visible light passed through a specimen

31
Q

What is resolution?

A

A measurement of the clarity of an optical instrument. The minimum distance which two separate points can be distinguished by an optical instrument

32
Q

Describe how a Transition Electron Microscope works

A

High energy beam of electrons passed through a thin slice of specimen. More dense structures absorb more electrons so they appear darker. The image is focussed onto a fluorescent screen or photographic plate using magnetic lenses

33
Q

Describe how a Scanning Electron Microscope works

A

Beam of electrons focused on the surface of a specimen using electromagnetic lenses. Reflected electrons hit a collecting device and are amplified to produce an image on a photographic plate

34
Q

Why do electron microscopes have a higher resolution than light microscopes?

A

Electrons have a much shorter wavelength than light and so can distinguish much smaller structures

35
Q

What type of microscope typically produces naturally colored images?

A

Light microscope

36
Q

What type of electron microscope produces 2D images?

A

Transmission electron microscope because the electrons are passed through the specimen

37
Q

Give 5 advantages of light microscopes

A

-cheap
-easy to use
-can visualize living cells
-portable and don’t always require electricity
-can visualize whole specimens

38
Q

Give 2 advantages of electron microscopes compared to light microscopes

A

They have much higher resolution and depth of field. They have much higher magnification.

Biology unit 3 (3 decks)

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