A Level Biology - OCR A an der University Of Cambridge | Karteikarten & Zusammenfassungen

Lernmaterialien für A Level Biology - OCR A an der University of Cambridge

Greife auf kostenlose Karteikarten, Zusammenfassungen, Übungsaufgaben und Altklausuren für deinen A Level Biology - OCR A Kurs an der University of Cambridge zu.

TESTE DEIN WISSEN

Describe the structure and functions of the rough endoplasmic reticulum. (2.1 g)

Lösung anzeigen
TESTE DEIN WISSEN

Structure

  • System of membranes containing fluid-filled cavities (cisternae) that are continuous with the nuclear membrane. 
  • The surface is coated in ribosomes because there is a large surface area.


Function

  • Intracellular transport system, for which cisternae act as channels to transport substances around the cell.
  • Proteins are assembled in the ribosomes that coat the surface. 
  • These produced proteins then actively pass into the cisternae to be transported to the GA. 
Lösung ausblenden
TESTE DEIN WISSEN

Describe the structure and function of lysosomes. (2.1 g)

Lösung anzeigen
TESTE DEIN WISSEN

Structure

  • Specialised vesicles that contain hydrolytic enzymes, keeping them separate from the cell. 


Function

  • Breaking down waste material in cells, such as old organelles.
  • They break down the pathogens that phagocytes engulf so are important to the immune system.
  • Involved in apoptosis.
Lösung ausblenden
TESTE DEIN WISSEN

Describe the structure and function of the nucleolus. (2.1 g)

Lösung anzeigen
TESTE DEIN WISSEN

Structure

  • Area inside the nucleus
  • Composed of proteins and RNA


Function

  • Ribosomes necessary for protein synthesis are produced here from RNA, which is used to produce rRNA.
Lösung ausblenden
TESTE DEIN WISSEN

Describe the structure and function of the smooth endoplasmic reticulum. (2.1 g)

Lösung anzeigen
TESTE DEIN WISSEN

Structure

  • A system of membranes containing fluid-filled cavities called cisternae.
  • No ribosomes on the surface.


Function

  • Involved in absorption, transport and synthesis of lipids from the gut.
  • Contains enzymes that catalyse lipid metabolic reactions, including the synthesis of cholesterol, lipids, phospholipids and steroid hormones.
Lösung ausblenden
TESTE DEIN WISSEN

Describe the structure and function of mitochondria. (2.1 g)

Lösung anzeigen
TESTE DEIN WISSEN

Structure

  • Double membrane
  • The inner membrane is highly folded to form cristae, containing enzymes used aerobic respiration
  • Fluid filled interior is called the matrix
  • Contains a small amount of DNA - (mt)DNA


Function

  • Site of the final stages of cellular respiration
  • Areas of high metabolic activity (eg liver cells) have lots of them
  • Self-replicating
Lösung ausblenden
TESTE DEIN WISSEN

How is magnification calculated?

Lösung anzeigen
TESTE DEIN WISSEN

Magnification = I/A

I = image size

A = actual size

Lösung ausblenden
TESTE DEIN WISSEN

Describe the structure and function of the cellulose cell wall. (2.1 g)

Lösung anzeigen
TESTE DEIN WISSEN

Structure

  • The cell wall surrounds the plasma membrane.
  • Made of bundles of cellulose fibers. 
  • Not found in animal cells. Fungi cell walls are made of chitin, prokaryotic cell walls are made of peptidoglycan. 


Function

  • Maintaining cell and overall plant shape.
  • Preventing turgid cell from bursting.
  • Permeable to enable substances to pass in and out of the cell. 
  • Acts as a defense mechanism to protect the cell contents from invading pathogens. 
Lösung ausblenden
TESTE DEIN WISSEN

What is used to calibrate the eyepiece graticule and what is it? What is the scale usually?

Lösung anzeigen
TESTE DEIN WISSEN
  • A stage micrometer - a glass slide with a scale on it that is placed onto the microscope stage
  • This scale is usually 2mm long with subdivisions of 10 micrometers apart. 
Lösung ausblenden
TESTE DEIN WISSEN

What is the role of centrioles in the formation of cilia and undulipodia?

Lösung anzeigen
TESTE DEIN WISSEN
  • Before the formation of cilia, centrioles multiply and line up underneath the plasma membrane.
  • From each centriole, microtubules sprout outwards.
  • This forms a cilium or undulipodium
Lösung ausblenden
TESTE DEIN WISSEN

Explain how specimens are stained and images and created in the two types of electron microscopes.

Lösung anzeigen
TESTE DEIN WISSEN

SEM

  • Specimen must be placed in a vacuum and coated with fine metal salts for staining. 
  • Electrons bounce off the surface of the specimen.
  • They are then focused onto a screen. 


TEM

  • Specimen is dehydrated and stained with metal salts. 
  • The electron beam passes through the specimen and the electrons are focused onto a screen. 
Lösung ausblenden
TESTE DEIN WISSEN

Why stain samples?

Lösung anzeigen
TESTE DEIN WISSEN
  • This helps scientists to distinguish between different cells and cell components - specimens are colourless when cut into thin sections. 


  • Live and dead cells, such as by using eosin, which only stains dead cells, such as sperm. 
Lösung ausblenden
TESTE DEIN WISSEN

Give four examples of stains for differential staining and their uses.

Lösung anzeigen
TESTE DEIN WISSEN
  • Acetic orcein binds to DNA and stains chromosomes dark red.
  • Eosin stains the cytoplasm.
  • Sudan red stains lipids.
  • Iodine solution stains cellulose yellow and starch blue-black. 
Lösung ausblenden
  • 5384 Karteikarten
  • 312 Studierende
  • 18 Lernmaterialien

Beispielhafte Karteikarten für deinen A Level Biology - OCR A Kurs an der University of Cambridge - von Kommilitonen auf StudySmarter erstellt!

Q:

Describe the structure and functions of the rough endoplasmic reticulum. (2.1 g)

A:

Structure

  • System of membranes containing fluid-filled cavities (cisternae) that are continuous with the nuclear membrane. 
  • The surface is coated in ribosomes because there is a large surface area.


Function

  • Intracellular transport system, for which cisternae act as channels to transport substances around the cell.
  • Proteins are assembled in the ribosomes that coat the surface. 
  • These produced proteins then actively pass into the cisternae to be transported to the GA. 
Q:

Describe the structure and function of lysosomes. (2.1 g)

A:

Structure

  • Specialised vesicles that contain hydrolytic enzymes, keeping them separate from the cell. 


Function

  • Breaking down waste material in cells, such as old organelles.
  • They break down the pathogens that phagocytes engulf so are important to the immune system.
  • Involved in apoptosis.
Q:

Describe the structure and function of the nucleolus. (2.1 g)

A:

Structure

  • Area inside the nucleus
  • Composed of proteins and RNA


Function

  • Ribosomes necessary for protein synthesis are produced here from RNA, which is used to produce rRNA.
Q:

Describe the structure and function of the smooth endoplasmic reticulum. (2.1 g)

A:

Structure

  • A system of membranes containing fluid-filled cavities called cisternae.
  • No ribosomes on the surface.


Function

  • Involved in absorption, transport and synthesis of lipids from the gut.
  • Contains enzymes that catalyse lipid metabolic reactions, including the synthesis of cholesterol, lipids, phospholipids and steroid hormones.
Q:

Describe the structure and function of mitochondria. (2.1 g)

A:

Structure

  • Double membrane
  • The inner membrane is highly folded to form cristae, containing enzymes used aerobic respiration
  • Fluid filled interior is called the matrix
  • Contains a small amount of DNA - (mt)DNA


Function

  • Site of the final stages of cellular respiration
  • Areas of high metabolic activity (eg liver cells) have lots of them
  • Self-replicating
Mehr Karteikarten anzeigen
Q:

How is magnification calculated?

A:

Magnification = I/A

I = image size

A = actual size

Q:

Describe the structure and function of the cellulose cell wall. (2.1 g)

A:

Structure

  • The cell wall surrounds the plasma membrane.
  • Made of bundles of cellulose fibers. 
  • Not found in animal cells. Fungi cell walls are made of chitin, prokaryotic cell walls are made of peptidoglycan. 


Function

  • Maintaining cell and overall plant shape.
  • Preventing turgid cell from bursting.
  • Permeable to enable substances to pass in and out of the cell. 
  • Acts as a defense mechanism to protect the cell contents from invading pathogens. 
Q:

What is used to calibrate the eyepiece graticule and what is it? What is the scale usually?

A:
  • A stage micrometer - a glass slide with a scale on it that is placed onto the microscope stage
  • This scale is usually 2mm long with subdivisions of 10 micrometers apart. 
Q:

What is the role of centrioles in the formation of cilia and undulipodia?

A:
  • Before the formation of cilia, centrioles multiply and line up underneath the plasma membrane.
  • From each centriole, microtubules sprout outwards.
  • This forms a cilium or undulipodium
Q:

Explain how specimens are stained and images and created in the two types of electron microscopes.

A:

SEM

  • Specimen must be placed in a vacuum and coated with fine metal salts for staining. 
  • Electrons bounce off the surface of the specimen.
  • They are then focused onto a screen. 


TEM

  • Specimen is dehydrated and stained with metal salts. 
  • The electron beam passes through the specimen and the electrons are focused onto a screen. 
Q:

Why stain samples?

A:
  • This helps scientists to distinguish between different cells and cell components - specimens are colourless when cut into thin sections. 


  • Live and dead cells, such as by using eosin, which only stains dead cells, such as sperm. 
Q:

Give four examples of stains for differential staining and their uses.

A:
  • Acetic orcein binds to DNA and stains chromosomes dark red.
  • Eosin stains the cytoplasm.
  • Sudan red stains lipids.
  • Iodine solution stains cellulose yellow and starch blue-black. 
A Level Biology - OCR A

Erstelle und finde Lernmaterialien auf StudySmarter.

Greife kostenlos auf tausende geteilte Karteikarten, Zusammenfassungen, Altklausuren und mehr zu.

Jetzt loslegen

Das sind die beliebtesten A Level Biology - OCR A Kurse im gesamten StudySmarter Universum

[AS]-Biology (OCR)

University of Birmingham

Zum Kurs
AQA biology a level

University of Cambridge

Zum Kurs
BIOLOGY

Free University of Tbilisi

Zum Kurs
AQA A-Level Biology

Rice University

Zum Kurs
Biology

University of Toronto

Zum Kurs

Die all-in-one Lernapp für Studierende

Greife auf Millionen geteilter Lernmaterialien der StudySmarter Community zu
Kostenlos anmelden A Level Biology - OCR A
Erstelle Karteikarten und Zusammenfassungen mit den StudySmarter Tools
Kostenlos loslegen A Level Biology - OCR A