It had been thriving for well over a billion years when a new
kind of cell appeared on the scene, one that harvested the sun's energy using a process that generates a highly toxic by - product — oxygen.
Now, researchers at Washington University School
of Medicine in St. Louis have found that a
kind of tolerance - promoting immune
cell appears in mice that carry a specific bacterium in their guts.
But now that we know what
kinds of changes occur as these
cells age, we can ask which
of these changes reverse themselves when an old
cell goes back to becoming a young
cell» — as
appeared to be the case when tissues
of older mice were exposed to blood from younger mice.
Year 6 Science Assessments and Tracking Objectives covered: Describe how living things are classified into broad groups according to common observable characteristics and based on similarities and differences, including micro-organisms, plants and animals Give reasons for classifying plants and animals based on specific characteristics Identify and name the main parts
of the human circulatory system, and describe the functions
of the heart, blood vessels and blood Recognise the impact
of diet, exercise, drugs and lifestyle on the way their bodies function Describe the ways in which nutrients and water are transported within animals, including humans Recognise that living things have changed over time and that fossils provide information about living things that inhabited the Earth millions
of years ago Recognise that living things produce offspring
of the same
kind, but normally offspring vary and are not identical to their parents Identify how animals and plants are adapted to suit their environment in different ways and that adaptation may lead to evolution Recognise that light
appears to travel in straight lines Use the idea that light travels in straight lines to explain that objects are seen because they give out or reflect light into the eye Explain that we see things because light travels from light sources to our eyes or from light sources to objects and then to our eyes Use the idea that light travels in straight lines to explain why shadows have the same shape as the objects that cast them Associate the brightness
of a lamp or the volume
of a buzzer with the number and voltage
of cells used in the circuit Compare and give reasons for variations in how components function, including the brightness
of bulbs, the loudness
of buzzers and the on / off position
of switches Use recognised symbols when representing a simple circuit in a diagram