Theo th\u1ea7y Nam, trong qu\u00e1 tr\u00ecnh h\u1ecdc m\u1ed9t s\u1ed1 em kh\u00f4ng \u0111\u1ecbnh h\u00ecnh r\u00f5 r\u00e0ng \u0111\u01b0\u1ee3c ph\u01b0\u01a1ng ph\u00e1p l\u00e0m b\u00e0i \u0111\u1ed1i v\u1edbi d\u1ea1ng b\u00e0i t\u1eadp tr\u1eafc nghi\u1ec7m. Do v\u1eady, khi l\u00e0m b\u00e0i, h\u1ecdc sinh c\u1ea7n suy ngh\u0129 k\u1ef9 v\u00e0 \u00e1p d\u1ee5ng ph\u01b0\u01a1ng ph\u00e1p ph\u00f9 h\u1ee3p v\u1edbi t\u1eebng b\u00e0i v\u00e0 b\u00e1m s\u00e1t 4 \u0111\u00e1p \u00e1n \u0111\u1ec3 t\u00ecm ra \u0111\u00e1p \u00e1n \u0111\u00fang nhanh nh\u1ea5t.<\/p>\n

V\u00ed d\u1ee5: \u0110\u1ec1 b\u00e0i cho A quy \u0111\u1ecbnh h\u1ea1t tr\u00f2n, alen l\u1eb7n a quy \u0111\u1ecbnh h\u1ea1t d\u00e0i; B quy \u0111\u1ecbnh h\u1ea1t ch\u00edn s\u1edbm, alen l\u1eb7n b quy \u0111\u1ecbnh h\u1ea1t ch\u00edn mu\u1ed9n. Hai gen n\u00e0y thu\u1ed9c c\u00f9ng m\u1ed9t nh\u00f3m gen li\u00ean k\u1ebft. Ti\u1ebfn h\u00e0nh cho c\u00e1c c\u00e2y h\u1ea1t tr\u00f2n, ch\u00edn s\u1edbm t\u1ef1 th\u1ee5 ph\u1ea5n, thu \u0111\u01b0\u1ee3c 1000 c\u00e2y \u0111\u1eddi con v\u1edbi 4 ki\u1ec3u h\u00ecnh kh\u00e1c nhau, trong \u0111\u00f3 c\u00f3 240 c\u00e2y h\u1ea1t tr\u00f2n, ch\u00edn mu\u1ed9n. Bi\u1ebft r\u1eb1ng m\u1ecdi di\u1ec5n bi\u1ebfn trong qu\u00e1 tr\u00ecnh sinh h\u1ea1t ph\u1ea5n v\u00e0 sinh no\u00e3n l\u00e0 nh\u01b0 nhau. Ki\u1ec3u gen v\u00e0 t\u1ea7n s\u1ed1 ho\u00e1n v\u1ecb gen (f) \u1edf c\u00e1c c\u00e2y \u0111em lai l\u00e0:<\/p>\n

A. AB\/ab v\u00e0 f = 20%.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 B. Ab\/aB v\u00e0 f = 20%.
\nC. Ab\/aB v\u00e0 f = 40%.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 D. AB\/ab v\u00e0 f = 40%.<\/p>\n

V\u1edbi c\u00e2u n\u00e0y, sau khi h\u1ecdc sinh \u0111\u1ecdc \u0111\u1ec1 th\u00ec ph\u1ea3i th\u1ea5y \u0111\u01b0\u1ee3c ngay l\u00e0 \u0111\u1ec1 h\u1ecfi t\u1ea7n s\u1ed1 ho\u00e1n v\u1ecb, m\u00e0 m\u1ecdi di\u1ec5n bi\u1ebfn trong qu\u00e1 tr\u00ecnh sinh h\u1ea1t ph\u1ea5n v\u00e0 sinh no\u00e3n l\u00e0 nh\u01b0 nhau. Khi \u0111\u00f3, h\u1ecdc sinh c\u1ea7n \u0111\u1ecbnh h\u00ecnh v\u00e0 ngh\u0129 ngay \u0111\u1ebfn c\u00e1c c\u00f4ng th\u1ee9c t\u00ednh nhanh. C\u1ee5 th\u1ec3, n\u1ebfu g\u1ecdi t\u1ef7 l\u1ec7 giao t\u1eed ab l\u00e0 x th\u00ec t\u1ef7 l\u1ec7 ki\u1ec3u h\u00ecnh l\u1eb7n s\u1ebd l\u00e0 x2. Khi \u0111\u00f3, t\u1ef7 l\u1ec7 ki\u1ec3u h\u00ecnh h\u1ea1t tr\u00f2n, ch\u00edn mu\u1ed9n (1 tr\u1ed9i + 1 l\u1eb7n) = 25% – x2 => 25% – x2 = 240\/1000 => x = 10% < 20%<\/p>\n

=> \u0110\u00e2y l\u00e0 giao t\u1eed sinh ra do ho\u00e1n v\u1ecb => Ki\u1ec3u gen c\u00e2y \u0111em lai c\u00f3 ki\u1ec3u gen\u00a0 v\u00e0 t\u1ea7n s\u1ed1 ho\u00e1n v\u1ecb f = 20%. Nh\u01b0 v\u1eady, \u0111\u00e1p \u00e1n \u0111\u00fang l\u00e0 B.<\/p>\n

H\u1ecdc sinh th\u01b0\u1eddng h\u1ecdc lan man, kh\u00f4ng bi\u1ebft \u0111\u1ea7u t\u01b0 s\u1eafp x\u1ebfp th\u1eddi gian, thi\u1ebfu ph\u01b0\u01a1ng ph\u00e1p h\u1ecdc t\u1eadp hi\u1ec7u qu\u1ea3 cho t\u1eebng ph\u1ea7n.<\/p>\n

V\u00ed d\u1ee5:<\/strong> Ph\u1ea7n n\u1ed9i dung T\u00ednh quy lu\u1eadt c\u1ee7a hi\u1ec7n t\u01b0\u1ee3ng di truy\u1ec1n c\u00f3 11 c\u00e2u trong \u0111\u1ec1, \u0111a ph\u1ea7n l\u00e0 b\u00e0i t\u1eadp. V\u1eady \u0111i\u1ec1u h\u1ecdc sinh c\u1ea7n l\u00e0 c\u00e1ch gi\u1ea3i c\u00e1c d\u1ea1ng b\u00e0i t\u1eadp quy lu\u1eadt di truy\u1ec1n ch\u1ee9 kh\u00f4ng ph\u1ea3i l\u00e0 \u0111\u1ea7u t\u01b0 h\u1ecdc qu\u00e1 nhi\u1ec1u l\u00fd thuy\u1ebft ph\u1ea7n n\u00e0y.<\/p>\n

Th\u1ea7y Nam cho bi\u1ebft th\u00eam, khi l\u00e0m b\u00e0i m\u00f4n Sinh, h\u1ecdc sinh hay v\u1ed9i v\u00e0ng, \u0111\u1ecdc kh\u00f4ng k\u1ef9 \u0111\u1ec1 d\u1eabn \u0111\u1ebfn hi\u1ec3u sai \u00fd h\u1ecfi, ch\u1ecdn nh\u1ea7m \u0111\u00e1p \u00e1n.<\/p>\n

V\u00ed d\u1ee5:<\/strong> \u0110\u1ec1 b\u00e0i cho v\u1edbi 4 lo\u1ea1i nucleotit A, U, G, X, th\u00ec s\u1ed1 b\u1ed9 ba m\u00e3 h\u00f3a c\u00f3 ch\u1ee9a nucleotit lo\u1ea1i G t\u1ed1i \u0111a c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c t\u1ea1o ra l\u00e0<\/p>\n

A. 27.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 B. 37.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 C. 35.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 D. 34.<\/p>\n

V\u1edbi c\u00e2u n\u00e0y, r\u1ea5t nhi\u1ec1u em \u0111\u1ecdc \u0111\u1ec1 kh\u00f4ng k\u1ef9 n\u00ean s\u1ebd l\u00e0m ngay l\u00e0: S\u1ed1 lo\u1ea1i b\u1ed9 ba ch\u1ec9 c\u00f3 3 lo\u1ea1i nucleotit A, U, X l\u00e0: 3x3x3 = 27 (b\u1ed9 ba). V\u1eady s\u1ed1 b\u1ed9 ba c\u00f3 ch\u1ee9a G l\u00e0: 64 \u2013 27 = 37 (b\u1ed9 ba) khi \u0111\u00f3 c\u00e1c em s\u1ebd ch\u1ecdn \u0111\u00e1p \u00e1n B. Tuy nhi\u00ean, \u0111\u1ec1 h\u1ecfi s\u1ed1 b\u1ed9 ba m\u00e3 h\u00f3a c\u00f3 ch\u1ee9a nucleotit lo\u1ea1i G. M\u00e0 trong 3 m\u00e3 k\u1ebft th\u00fac th\u00ec c\u00f3 hai m\u00e3 l\u00e0 UAG, UGA c\u00f3 G. Do \u0111\u00f3, s\u1ed1 b\u1ed9 ba m\u00e3 h\u00f3a c\u00f3 G = 37 \u2013 2 = 35 => \u0110\u00e1p \u00e1n \u0111\u00fang ph\u1ea3i l\u00e0 C.<\/p>\n

Theo th\u1ea7y Nam, khi l\u00e0m b\u00e0i m\u00f4n Sinh th\u01b0\u1eddng c\u00f3 c\u00e1c c\u00f4ng th\u1ee9c t\u00ednh nhanh ho\u1eb7c c\u00e1c \u201cth\u1ee7 thu\u1eadt\u201d \u0111\u1ec3 x\u1eed l\u00fd v\u1edbi c\u00e2u h\u1ecfi l\u00fd thuy\u1ebft \u0111\u1ec3 t\u00ecm ra k\u1ebft qu\u1ea3 nhanh g\u1ecdn<\/p>\n

H\u1ecdc sinh th\u01b0\u1eddng ch\u1ee7 quan v\u1edbi c\u00e2u h\u1ecfi l\u00fd thuy\u1ebft. \u0110\u00e2y l\u00e0 m\u1ed9t sai l\u1ea7m l\u1edbn \u0111\u1ed1i v\u1edbi c\u00e1c em. B\u1edfi v\u00ec l\u00ed thuy\u1ebft chi\u1ebfm 6 \u0111i\u1ec3m trong \u0111\u1ec1 thi \u0111\u1ea1i h\u1ecdc nh\u01b0ng r\u1ea5t nhi\u1ec1u em khi h\u1ecdc b\u00e0i th\u01b0\u1eddng coi nh\u1eb9 h\u1ecdc c\u00e1c ph\u1ea7n l\u00fd thuy\u1ebft. Vi\u1ec7c n\u00e0y d\u1eabn \u0111\u1ebfn h\u1ecdc sinh kh\u00f4ng l\u1eafm v\u1eefng b\u1ea3n ch\u1ea5t c\u1ee7a ki\u1ebfn th\u1ee9c n\u00ean \u0111i thi \u0111\u00e1p \u00e1n \u0111\u00fang th\u00ec nh\u1ea7m t\u01b0\u1edfng l\u00e0 sai, \u0111\u00e1p \u00e1n sai nh\u1ea7m t\u01b0\u1edfng l\u00e0 \u0111\u00fang.<\/p>\n

V\u00ed d\u1ee5:<\/strong> \u0110\u1ec1 b\u00e0i h\u1ecfi, c\u01a1 ch\u1ebf \u0111i\u1ec1u ch\u1ec9nh s\u1ed1 l\u01b0\u1ee3ng c\u00e1 th\u1ec3 c\u1ee7a qu\u1ea7n th\u1ec3 kh\u00f4ng ph\u1ea3i l\u00e0:<\/p>\n

A. T\u1ef7 l\u1ec7 sinh t\u0103ng th\u00ec t\u1ec9 l\u1ec7 t\u1eed gi\u1ea3m trong qu\u1ea7n th\u1ec3.
\nB. S\u1ef1 c\u1ea1nh tranh c\u00f9ng lo\u00e0i v\u00e0 s\u1ef1 di c\u01b0 c\u1ee7a m\u1ed9t b\u1ed9 ph\u1eadn hay c\u1ea3 qu\u1ea7n th\u1ec3.
\nC. S\u1ef1 thay \u0111\u1ed5i m\u1ee9c sinh s\u1ea3n v\u00e0 t\u1eed vong d\u01b0\u1edbi t\u00e1c \u0111\u1ed9ng c\u1ee7a nh\u00e2n t\u1ed1 v\u00f4 sinh v\u00e0 h\u1eefu sinh.
\nD. S\u1ef1 \u0111i\u1ec1u ch\u1ec9nh v\u1eadt \u0103n th\u1ecbt v\u00e0 v\u1eadt k\u00fd sinh.<\/p>\n

V\u1edbi c\u00e2u n\u00e0y, khi h\u1ecdc sinh ch\u01b0a hi\u1ec3u r\u00f5 n\u1ed9i dung h\u1ecfi nhi\u1ec1u em ngh\u0129 \u0111\u00e1p \u00e1n \u0111\u00fang s\u1ebd kh\u00f4ng ph\u1ea3i l\u00e0 A m\u00e0 t\u1eadp trung v\u00e0o m\u1ed9t m\u1ed9t ch\u1ecdn m\u1ed9t trong 3 \u0111\u00e1p \u00e1n B, C, D. Tuy nhi\u00ean, \u1edf c\u00e2u h\u1ecfi n\u00e0y \u0111\u00e1p \u00e1n \u0111\u00fang l\u1ea1i l\u00e0 A v\u00e0 nhi\u1ec1u em h\u1ecdc sinh kh\u00f4ng \u0111\u1ecdc k\u1ef9 \u0111\u1ec1 b\u00e0i \u0111\u00e3 b\u1ecb l\u1eeba.<\/p>\n

B\u00ed quy\u1ebft gi\u00e0nh \u0111i\u1ec3m cao m\u00f4n Sinh<\/strong><\/h3>\n

Theo th\u1ea7y Nam, \u0111\u1ec3 \u0111\u1ea1t \u0111i\u1ec3m cao m\u00f4n Sinh trong k\u1ef3 thi \u0111\u1ea1i h\u1ecdc b\u1eaft bu\u1ed9c h\u1ecdc sinh ph\u1ea3i c\u1ea9n th\u1eadn, l\u00e0m b\u00e0i logic \u0111\u00fang khoa h\u1ecdc. Tr\u01b0\u1edbc ng\u00e0y \u0111i thi c\u00e1c em n\u00ean chu\u1ea9n b\u1ecb \u0111\u1ea7y \u0111\u1ee7 nh\u1eefng v\u1eadt d\u1ee5ng c\u1ea7n thi\u1ebft nh\u01b0 t\u1ea9y, m\u00e1y t\u00ednh, b\u00fat bi, b\u00fat ch\u00ec 2B v\u00f3t c\u1ea3 hai \u0111\u1ea7u (v\u00f3t hai \u0111\u1ea7u \u0111\u1ec3 c\u1ee9 c\u1ea7m v\u00e0o c\u00e1i b\u00fat ch\u00ec l\u00e0 ta c\u00f3 th\u1ec3 t\u00f4 ngay).<\/p>\n

Khi nh\u1eadn \u0111\u1ec1 thi, h\u1ecdc sinh l\u00e0m b\u00e0i thi theo 3 v\u00f2ng.<\/strong><\/h4>\n

V\u00f2ng 1,<\/strong> c\u00e1c em l\u00e0m c\u00e2u h\u1ecfi d\u1ec5 tr\u01b0\u1edbc. Khi \u0111\u1ecdc xong \u0111\u1ec1 ph\u00e1t hi\u1ec7n ngay ra \u0111\u00e1p \u00e1n \u0111\u00fang th\u00ec ph\u1ea3i t\u00f4 ngay v\u00e0o phi\u1ebfu tr\u1ea3 l\u1eddi tr\u1eafc nghi\u1ec7m. C\u00e2u n\u00e0o h\u1ecdc sinh kh\u00f4ng l\u00e0m \u0111\u01b0\u1ee3c th\u00ec c\u1ea7n \u0111\u00e1nh d\u1ea5u \u1edf ngay tr\u00ean \u0111\u1ec1 \u0111\u1ec3 ti\u1ec7n cho vi\u1ec7c theo d\u00f5i.<\/p>\n

V\u00f2ng 2<\/strong>, h\u1ecdc sinh ch\u1ecdn l\u00e0m c\u00e1c c\u00e2u h\u1ecfi m\u1ee9c trung b\u00ecnh. \u1ede d\u1ea1ng c\u00e2u h\u1ecfi n\u00e0y \u0111\u00f2i h\u1ecfi h\u1ecdc sinh ph\u1ea3i suy ngh\u0129 k\u1ef9 h\u01a1n. Tuy nhi\u00ean, n\u1ebfu kh\u00f4ng chu \u00fd th\u1eddi gian th\u00ec h\u1ecdc sinh r\u1ea5t d\u1ec5 b\u1ecb r\u01a1i v\u00e0o tr\u1ea1ng th\u00e1i h\u1ebft gi\u1edd m\u00e0 ch\u01b0a l\u00e0m xong v\u00f2ng n\u00e0y. V\u00ec v\u1eady, h\u1ecdc sinh c\u1ea7n \u0111\u1eb7c bi\u1ec7t chu \u00fd th\u1eddi gian khi l\u00e0m v\u00f2ng n\u00e0y \u0111\u1ec3 \u0111\u1ea1t hi\u1ec7u qu\u1ea3 cao.<\/p>\n

V\u00f2ng 3<\/strong>, c\u00e1c em ch\u1ecdn l\u00e0m c\u00e2u h\u1ecfi kh\u00f3. \u0110\u00e2y l\u00e0 d\u1ea1ng c\u00e2u h\u1ecfi c\u1ea7n h\u1ecdc sinh ph\u1ea3i suy ngh\u0129 nhi\u1ec1u ho\u1eb7c ph\u1ea3i c\u00f3 ph\u01b0\u01a1ng ph\u00e1p gi\u1ea3i \u0111\u1eb7c bi\u1ec7t v\u1edbi t\u00ecm ra \u0111\u00e1p \u00e1n. G\u1eb7p d\u1ea1ng n\u00e0y \u0111\u00f4i khi h\u1ecdc sinh ngh\u0129 th\u1eadt k\u1ef9 th\u00ec ra, nh\u01b0ng \u0111\u00f4i khi c\u00e0ng ngh\u0129 c\u00e0ng th\u1ea5y b\u1ebf t\u1eafc. Do \u0111\u00f3, n\u1ebfu th\u1eadt s\u1ef1 b\u1ebf t\u1eafc h\u1ecdc sinh c\u00f3 th\u1ec3 d\u00f9ng ph\u01b0\u01a1ng \u00e1n lo\u1ea1i tr\u1eeb d\u1ea7n nh\u1eefng ph\u01b0\u01a1ng \u00e1n b\u1ea3n th\u00e2n m\u00ecnh cho l\u00e0 sai.<\/p>\n","protected":false},"excerpt":{"rendered":"

Th\u1ea7y Th\u1ecbnh Nam, gi\u00e1o vi\u00ean chuy\u00ean luy\u1ec7n thi m\u00f4n Sinh, th\u00e0nh vi\u00ean H\u1ed9i \u0111\u1ed3ng x\u00e2y d\u1ef1ng ng\u00e2n h\u00e0ng \u0111\u1ec1 thi Qu\u1ed1c gia chia s\u1ebb v\u1edbi c\u00e1c th\u00ed sinh chu\u1ea9n b\u1ecb… <\/p>\n","protected":false},"author":1,"featured_media":917,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8,9],"tags":[],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/posts\/916"}],"collection":[{"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/comments?post=916"}],"version-history":[{"count":0,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/posts\/916\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/media\/917"}],"wp:attachment":[{"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/media?parent=916"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/categories?post=916"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/onthitot.com\/wp-json\/wp\/v2\/tags?post=916"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}