Topic 3- movement across cells
What is the net movement of particles from a region of high concentration to a region of low concentration called?
diffusion
Name the life process that involves chemical reactions inside cells to keep the organism alive.
metabolism
Which organelle is responsible for aerobic respiration and energy production?
mitocondria
What is the science of naming, classifying, and grouping organisms called?
Taxanomy
What type of transport moves ions against their concentration gradient, and what energy source does it use?
Active transport; uses ATP.
What is the membrane allows some substances to pass through but blocks others called? Give an example.
partially permeable membrane - cell membrane
A fungus secretes enzymes onto its food and absorbs the digested products. Which two characteristics of living organisms are involved?
Nutrition and excretion
Name one specialised cell in the human body and state its function.
any valid answer
Which naming system uses two names (genus and species) to identify organisms, and who developed it?
System: Binomial nomenclature
Developed by: Carl Linnaeus
Name the 2 phylum that separates the kingdom animalia
Arthropods, vertebrate
define osmosis
movement of water molecules across a partially permeable membrane from high water potential to low water potential through partially permeable membrane
A seed can remain dormant for many years without growing. Which two characteristics of living organisms are still present during dormancy?
Respiration and sensitivity (very slow metabolic activity)
Red blood cells do not contain a nucleus. Explain how this structural adaptation improves their function.
The absence of a nucleus provides more space for haemoglobin, allowing the cell to carry more oxygen.
List the main hierarchical levels of classification in order from largest to smallest.
Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species
Name the characteristic that distinguishes angiosperms from gymnosperms.
Angiosperms produce flowers and fruits; gymnosperms do not.
A plant cell placed in a concentrated salt solution loses water and the cytoplasm pulls away from the cell wall. What is this process and solution called?
plasmolysis, hypertonic
Why is movement considered a characteristic of living organisms even in plants?
Plants show movement through growth responses such as phototropism and opening/closing of flowers.
Explain why multicellular organisms require specialised cells instead of one generalised cell performing all functions.
Specialised cells allow division of labour, making processes more efficient and enabling organisms to grow larger and perform complex functions.
A cladogram shows that species A and B share a more recent common ancestor than species C. Explain what this tells us about the evolutionary relationship of A, B, and C.
A and B are more closely related to each other than either is to C.
They share more characteristics inherited from their recent common ancestor.
C diverged earlier and shares fewer derived characteristics with A and B.
Name characteristics of an insect
Body is divided into three main parts:Exoskeleton:# pairs of jointed legs;Antennae
Why does diffusion become inefficient in large multicellular organisms?
Because the diffusion distance becomes too large and the surface area to volume ratio decreases, slowing down the rate of exchange.
Why is reproduction not considered essential for the survival of an individual organism, but essential for the survival of a species?
An individual organism can survive without reproducing, but reproduction is required to produce new individuals to continue the species and prevent extinction.
Explain why diffusion alone is insufficient to meet the oxygen requirements of a large multicellular organism. How multicellular cell transport oxygen?
Cells are deep inside tissues, so diffusion distance is too long.
Oxygen would not reach all cells quickly enough.
Multicellular organisms need specialised organs and organ systems (lungs, blood, circulatory system) to transport oxygen efficiently.
A biologist classifies three species based on shared derived characteristics: presence of backbone, lungs, and scales.
Species M has all three traits.
Species N has backbone and lungs but no scales.
Species O has only backbone.
Question:
Explain the order of divergence from the common ancestor and the reasoning.
Species O diverged first (only has backbone).
Species N diverged next (has backbone and lungs).
Species M diverged last (has all three traits).
Reason: More shared derived characteristics indicate closer relationship and more recent divergence.
How plants are categorized to its phylum - Name example and characteristics for each of them
Bryophytes and Tracheophytes
Non-vascular (no xylem or phloem)
No true roots, stems, or leaves
Require water for fertilization
Dominant gametophyte stage in life cycle
Have vascular tissues:
Xylem for water and minerals
Phloem for food transport
Possess true roots, stems, and leaves