AQA Biology 8461 - Cell Biology Flashcards

57 vocabulary flashcards based on AQA Biology 8461 Cell Biology notes.

Eukaryotic cell

A cell whose genetic material is enclosed inside a nucleus.

Prokaryotic cell

A smaller cell with no nucleus whose genetic material is not enclosed in a nucleus.

Nucleus

A cell structure that contains genetic material and controls the activities of the cell.

Cytoplasm

The part of the cell where most chemical reactions take place.

Cell membrane

A cell structure that controls the movement of substances into and out of the cell.

Mitochondria

Cell structures that are the site of aerobic respiration.

Ribosomes

Cell structures that are the site of protein synthesis.

Chloroplasts

Structures that contain chlorophyll and are the site of photosynthesis.

Permanent vacuole

A plant cell structure that contains cell sap.

Cellulose cell wall

A plant cell structure that strengthens the cell.

Bacterial DNA arrangement

Arranged as a single DNA loop as the main genetic material, along with potential plasmids.

Bacterial nucleus

Absent in bacterial cells, as their genetic material is not enclosed in a nucleus.

Sperm cell mitochondria adaptation

Presence of many mitochondria to provide energy for movement.

Nerve cell adaptation

Long structure enabling electrical impulses to travel long distances.

Root hair cell adaptation

A large surface area that increases the uptake of water and mineral ions.

Cell differentiation

The process by which a cell changes to become specialised for its function.

Animal cell differentiation timing

Occurs at an early stage of development for most animal cells.

Plant cell differentiation ability

Ability retained by many plant cells to differentiate throughout life.

Electron microscope advantage

Shows more cell detail than light microscopes because of much higher magnification and resolving power.

Resolution

The ability to distinguish two close points as separate.

Magnification equation

$$\text{Magnification} = \frac{\text{image size}}{\text{real size}}$$

Unit conversion for magnification

Converting image size and real size into the same units prior to calculation.

Pre-mitosis cell growth

Stage where the cell grows, increases its sub-cellular structures, and replicates its DNA before division.

Mitosis process

Process where one set of chromosomes is pulled to each end of the cell and the nucleus divides.

Mitosis products

Two genetically identical daughter cells.

Importance of mitosis

Essential for growth, repair, and replacement of cells.

Stem cell

An undifferentiated cell that can divide and differentiate into specialised cells.

Human embryonic stem cells

Stem cells found in early embryos.

Adult stem cells

Stem cells found in some adult tissues, such as bone marrow.

Medical application of stem cells

Use of stem cells to replace damaged or diseased cells.

Meristems

Regions in plants containing stem cells that can differentiate into many types of plant cell.

Binary fission

Simple cell division by which bacteria reproduce.

Rapid bacterial multiplication conditions

Requires enough nutrients and a suitable temperature.

Uncontaminated culture

A culture containing only the microorganism being investigated.

Sterilisation of Petri dishes and culture media

Procedure to kill unwanted microorganisms and prevent contamination.

Sterilisation of an inoculating loop

Procedure to prevent unwanted microorganisms from contaminating the culture.

Securing the Petri-dish lid

Action taken to reduce contamination by microorganisms from the environment.

Incubation temperature for school cultures

Kept at no more than $25\,^\circ\text{C}$ to reduce the chance of growing harmful pathogens.

Zone of inhibition

The clear area around an antibiotic on an agar plate measured to assess the antibiotic's effectiveness.

Diffusion

The net movement of particles from an area of higher concentration to an area of lower concentration.

Factors increasing diffusion rate

A steeper concentration gradient, higher temperature, and larger membrane surface area.

Substances transported by diffusion in humans

Oxygen, carbon dioxide, and urea.

Exchange in single-celled organisms

Diffusion across the cell membrane enabled by a large surface-area-to-volume ratio, removing the need for specialised exchange surfaces.

Exchange in large multicellular organisms

Requirement for specialised exchange surfaces due to a smaller surface-area-to-volume ratio that prevents diffusion alone from meeting needs.

Effective exchange surface features

A large surface area and thin membrane, often accompanied by a good blood supply and ventilation in animals.

Osmosis

The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.

Moving substance in osmosis

Water molecules.

Partially permeable membrane

The required membrane type through which water diffuses during osmosis.

Required osmosis practical

Investigation testing the effect of different salt or sugar concentrations on the mass of plant tissue.

Percentage change in mass equation

$$\text{Percentage change in mass} = \left(\frac{\text{change in mass}}{\text{initial mass}}\right) \times 100$$

Increase in plant-tissue mass

Indicates that water entered the cells by osmosis.

Decrease in plant-tissue mass

Indicates that water left the cells by osmosis.

Active transport

Movement of substances from a more dilute solution to a more concentrated solution, against the concentration gradient, using energy from respiration.

Active transport in root hair cells

Process used to absorb mineral ions when their concentration is lower in the soil than inside the root hair cells.

Active transport in the small intestine

Process allowing glucose to be absorbed into the blood even when its concentration is lower in the intestine than in the blood.

Energy requirement in transport processes

Active transport requires energy, whereas diffusion does not.

Water involvement in transport processes

Osmosis specifically involves water, whereas general diffusion refers to particles.