2.1 Cell Structure Flashcards Preview

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Flashcards in 2.1 Cell Structure Deck (37):
1

What is the cell surface membrane and its function?

The membrane found on the surface of all cells. Made up of phospholipids.

It regulates the movement of substances into and out of the cell.
Receptor molecules on surface allow chemical response ie) hormones.

2

What is the nucleus and what's its function?

Large organelle surrounded by a nuclear envelope with pores. It contains chromosomes and a nucleolus

Controls the cell activities and DNA contains the instructions to make proteins

3

What is a mitochondria and its function?

Oval shaped double membrane, with the inner folded to give a structure called cristae. Inside is the matrix which contains respiratory enzymes.

The site of aerobic respiration and production of ATP.

4

What is a chloroplast and its function?

Small organelle found in plants. Surrounded by a double membrane it has membranes inside called thylakoids which are stacked to produce grana, suspended in stroma fluid

This is where photosynthesis takes place

5

What is the Golgi apparatus and its function?

A group of fluid filled membrane bound flattened stacks.

It processes and packages new lipids proteins and lysosomes.

6

What is the vesicle and its function?

Small fluid filled sac in the cytoplasm that has broken from the Golgi body.

It stores and transports out of the cell the materials made by the Golgi

7

What is the lysosome and its function?

A type of Golgi vesicle

Contains digestive lysosome enzymes that can be used to break down worn out organelle or invading pathogens.

8

What is a ribosome and its function?

A small free floating organelle in the cytoplasm. Made of proteins and RNA

The site where proteins are made.

9

What is the rough endoplasmic reticulum and its function?

A system of membrane enclosed fluid. The surface is covered with ribosomes.

Folds and processes proteins made at the ribosomes

10

What is the smooth endoplasmic reticulum and its function?

Similar to RER but no ribosomes

Synthesises and processes lipids

11

What is the cell wall and its function?

A rigid structure which surrounds cells in plants algae and fungi. Made of cellulose (or chitin in fungi)

Supports and provides rigidity to cell

12

What is the plant vacuole and its function?

A membrane bound organelle in the cytoplasm of cells containing sap- weak sugar and salt solution

Helps maintain the pressure in the cell and increase rigidity
Stops plants wilting
Isolates unwanted chemicals

13

What is a eukaryote?

More complicated than prokaryotes, all animal plant algae and fungi cells are eukaryotic.

14

List the component of eukaryotic cells

Cell surface membrane
RER
SER
Nucleus
Nucleolus
Mitochondrion
Lysosome
Ribosomes
Nuclear envelope
Golgi
Vesicle
Cytoplasm

15

List the components of plant cells

Cell surface membrane
Chloroplast
RER
Plasmodemata
Mitochondria
Golgi
Vacuole
SER
Cytoplasm
Nucleolus
Nucleus
Nuclear envelope
Ribosome
Cell wall

16

List the component of algal cells

Mitochondria
SER
RER
Golgi
Cytoplasm
Nucleolus
Nucleus
Nuclear envelope
Chloroplast
Cell surface membrane
Vacuole
Cell wall
Ribosomes

17

What are plasmodemata?

Channels in the cell wall for exchanging substances between cells

18

What is a chloroplast?

The organelle used in photosynthesis

19

Show a flowchart of cell organisation

Specialised cells grouped -> tissues

Tissues. -> organs

Organs -> organ systems

20

What is a tissue?

A specialised group of cells working together to perform a particular function

21

What are the major structures in a prokaryotic cell?

Cytoplasm contains smaller ribosomes
Phospholipid cell surface membrane
Cell wall adds rigidity and is made of glycoproteins
They have a capsule of mucous to prevent attack by immune systems
Plasmids- small loops of DNA
Free floating DNA to replace the nucleus
Flagella to propel movement

22

How do you calculate magnification?

Size of image
---------------------
Size of real object

23

How to convert units used in microscopy?

mm. =1 mm
um. =0.001 mm
nm. =0.000001mm


To convert the table, times by 1000 down and divide by 1000 up.

24

What is resolution?

How well the microscope can distinguish between 2 points

25

What is magnification?

How much bigger the image is than the specimen.

Eyepiece lens* objective lens= magnification

26

What is a TEM?

A transmission electron microscope.

Beams of electrons are aimed at the specimen and the denser sections absorb more electrons giving a darker image.

27

What is an SEM?

A scanning electron microscope.

A beam of electrons are scattered across the specimen to give a 3D image.

28

What are the advantages of a TEM?

They give high resolution images and can show small images

29

What are the disadvantages of TEM?

Can only be used on thin specimens
Non living specimens- in a vacuum environment
Black and white images unless false coloured
Artefacts may be produced
Long preparation time
Expensive

30

What are the advantages of SEM?

Can be used on thick specimens
Gives a 3D image

31

What are the disadvantages of SEM?

Give low resolution images
Non living specimen- vacuum environment
Black and white images unless false coloured
Artefacts may be produced
Long preparation time
Expensive

32

What are microscope artefacts?

They are seen in the microscope but aren't part of the cell
They may arise due to production and treatment of the specimen.

33

Cell Fractionation:
What is homogenisation?

Breaking the cells by grinding or blending in a blender to break the cell membrane

(EXAM ANSWERS NEED HOW ITS DONE NOT JUST HOMOGENIZED)

34

Cell fractionation:
What are the conditions that the solution must be kept in and why?

Cold - to reduce activity of enzymes which break the cell
Isotonic- prevent osmotic loss or gain and osmotic lysis
Buffer- maintain the pH

35

Cell fractionation:
What is filtration?

The homogenised cell is passed through a gauze to separate large cell debris.

36

Cell fractionation:
What is ultracentrifugation?

Using a centrifuge to spin the remaining fluid and solution to separate the different organelles at varying speeds. The organelles separate by mass.

37

Cell fractionation:
In which order are the organelles separated in ultracentrifugation?

In order of mass heaviest to lightest

Nuclei
Chloroplast (plants)
Mitochondria
Lysosomes
Endoplasmic reticulum
Ribosomes